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52: Care of the Patient with Substance Use Disorder
Maureen F. Cooney
The use of illicit substances is widespread in the United States. The effects of alcohol, prescription medications, and illicit substances can affect patient outcomes and are a concern in the perioperative setting. It is important for perioperative nurses to be knowledgeable about substance use disorders as patients with these disorders may present in all surgical and procedural settings. Perianesthesia nurses must possess skills to assess and manage patients under the influence of or withdrawing from these substances. This chapter contains an overview of substances commonly used or misused as well as special considerations for perianesthesia nursing care.
alcohol; amphetamines; barbiturates; benzodiazepines; cannabinoids; club and date rape drugs; cocaine; complications; dissociatives; hallucinogens; inhalants; misuse; nursing care; opioid analgesics; substance use disorder; withdrawal
The use of illicit substances is widespread in the United States. In 2019, 57.2 million Americans aged 12 years or older (1 in 5, or 20.8%) used an illicit drug. Although marijuana has continued to be the most commonly used drug, the nonmedical use of prescription pain relievers (opioids) is the second most commonly used class of medications.1 In 2019, 3.5% of the U.S. population aged 12 years or older reported misuse of prescription opioids. This percentage shows an overall decline in misuse over the previous three years to 2016–2018; however, as in previous years, the most common source for obtaining opioids was a friend or relative. Perianesthesia nurses need to be informed about the care of patients who misuse drugs and have substance use disorders (SUDs). Misuse of marijuana, opioids, and other drugs including amphetamines, cocaine, hallucinogens, alcohol, barbiturates, benzodiazepines, and newer, less predictable synthetic medications by those undergoing surgical procedures poses potential challenges to patient outcomes and safety during the perioperative period.
Terminology and criteria used to diagnose SUDs have been revised since 2013. The phrase substance use disorder (SUD) has replaced the term addiction which was previously used to describe the compulsive use of a substance, impaired control over its use, craving for the substance, and continued use despite harm.2 SUD is a chronic condition with periods of exacerbation and remission; it is characterized by use of the problematic substance (e.g., alcohol, sedative, stimulant, opioids) for nonmedical reasons which results in various degrees of impaired control, social impairment, and hazardous use.2 The disorder can exist along a continuum ranging from mild to severe, depending on the number of symptoms that are present.2
It is important to clarify other terms which are often misinterpreted and may negatively impact patient care. Physical dependence is a term used to describe an altered physiologic state caused by repeated administration of specific classes of substances (e.g., opioids) that necessitates the continued administration of the substance to prevent withdrawal or abstinence syndromes characteristic for that drug.2,3 Physical dependence does not necessarily constitute SUD, but regardless of the reason for use of the substance, the abrupt withdrawal or rapid reversal of the substance may result in withdrawal symptoms.
Tolerance is a state in which, after repeated administration of a substance, a given dose will produce a decreased effect (or decreased side effect), and increasingly larger doses are needed to obtain the effect of the original dose.2,3
The effects of alcohol, prescription medications, and illicit substances can affect patient outcomes and are a concern in the perioperative setting. It is important for perioperative nurses to be knowledgeable about SUDs as patients with these disorders may present in all surgical and procedural settings. Perianesthesia nurses must possess skills to assess and manage patients under the influence of or withdrawing from these substances. Nursing care includes ensuring the physical and psychological well-being of the patient. The following sections contain an overview of substances commonly used or misused as well as special considerations for perianesthesia nursing care.
The substances are grouped for discussion as follows: (1) opioid analgesics; (2) general central nervous system (CNS) depressants such as alcohol, benzodiazepines, and barbiturates; (3) CNS sympathomimetics such as amphetamines and cocaine; (4) cannabinoids such as marijuana and synthetic cannabinoid products; (5) hallucinogens such as lysergic acid diethylamide (LSD); (6) dissociatives such as phencyclidine (PCP) and ketamine; (7) inhalants; and (8) club and date rape drugs. Because the literature is sparse on the potential effects of many of these substances, this chapter can only provide general information for perianesthesia nursing care in this population. See Table 52.1 for categories of substances, possible medical complications, symptoms or signs of use or abuse, and signs of withdrawal.
Categories of Substances, Possible Medical Complications, Symptoms or Signs of Use or Abuse, and Signs of Withdrawal⁎
|Possible Medical Complications|
|Signs or Symptoms of Use or Abuse|
|Signs of Withdrawal|
Infections from injection
|Altered mental status (overdose)|
Decreased respirations (overdose)
Injection scars or needle marks
Miosis (pinpoint pupils)
Thrombophlebitis at injection sites
Gastrointestinal (cramps, diarrhea, vomiting)
Lacrimation (watery eyes)
Rhinorrhea (runny nose)
Thermoregulation disturbances (chills, sweating)
|General CNS Depressants|
|Complications secondary to alcoholic cirrhosis (hemorrhage, sepsis, infection)|
|Apneic episodes (those with sleep apnea)|
Impaired reaction time
Increased emotional outbursts
|6–24 hours after abstinence|
Seizures (8–24 hours after)
72–96 hours after abstinence
Tachycardia, tremor, diaphoresis, fever, global confusion, disorientation, hallucinations, insomnia
Flunitrazepam (date rape)
|Respiratory depression (from overdose)|
Delirium (from withdrawal)
Seizures (from withdrawal)
Bruxism (jaw clenching)
Injection scars, needle marks
Mydriasis (dilated pupils)
Nausea and vomiting
Synthetic cannabinoid products (K2, Spice, Dream, etc.)
|Case reports r/t synthetic products:|
Acute kidney injury
Psychological: irritability, anxiety, restlessness
Less common: gastrointestinal distress, nausea, chills, diaphoresis, muscle twitches
|Lysergic acid diethylamide (LSD)|
|Acute toxic delirium|
Hyperthermic crisis (rare)
Mydriasis (pupillary dilation)
Acute renal failure
⁎ Not a complete list.
From Herron AJ, Brennan TK. The ASAM essentials of addiction medicine. 2nd ed. Lippincott, Williams & Wilkins: Philadelphia, PA; 2015.
Addiction A term that has been replaced by substance use disorder (SUD).
Physical Dependence Describes an altered physiologic state caused by repeated administration of specific classes of substances (e.g., opioids) that necessitates the continued administration of the substance to prevent withdrawal or abstinence syndromes characteristic for that drug.2,3
Substance Use Disorder Characterized by use of the problematic substance (e.g., alcohol, sedative, stimulant, opioids) for nonmedical reasons which results in various degrees of impaired control, social impairment, and hazardous use.2
Tolerance A state of adaptation in which exposure to a drug induces changes that result in diminution of one or more of a drug’s effects or its side effects over time.2,3
Opioids are natural and synthetic substances related to opium derived from poppies.3,4 Opioids (e.g., codeine, fentanyl, hydrocodone, hydromorphone, methadone, morphine, oxycodone, and oxymorphone) are used to treat acute and chronic pain. Pain relief occurs from the opioids’ effect primarily on the opioid receptors (mu, kappa, delta) in the CNS.4 The CNS effects of opioids can also lead to adverse outcomes such as mental status changes, advancing sedation, and respiratory depression.5 Since 2000, or even earlier, opioids have been widely used for the treatment of both acute and chronic pain.4 Illicit use of prescription opioids has increased as well, and opioids are only second to marijuana in substances used for nonmedical purposes.1 Tolerance to these medications and cross-tolerance with other opioid analgesics develops over time. Use of long-term opioid therapy can cause physical dependence and precipitate acute withdrawal symptoms if the medication is abruptly discontinued; however, there is significant variability in the duration of opioid use that would result in physical dependence.4 The use of prescription opioids, for some people, poses a risk for the development of opioid use disorder (OUD). There are a number of factors that contribute to this risk, including genetic predisposition, demographic factors, psychosocial factors, comorbid psychological conditions, SUD histories, and opioid-specific characteristics.6
Heroin, first synthetically derived from morphine in the 1870s, is abused by injection, inhalation, or smoking.7 Heroin is an illicit substance with very rapid and strong physiological and psychoactive effects.8 It is often combined with variable amounts of fentanyl, which adds to the potency of the product and the unpredictability of its effects.9 In addition to risks for advancing sedation and respiratory depression, heroin overdose can lead to noncardiogenic pulmonary edema.10
National and statewide policies related to restrictions in opioid prescribing and increased awareness of prescription opioid risks have coincided with reductions in opioid prescribing practices in the United States since 2012.11 However, despite reductions in the prescription of opioids, deaths related to opioid overdose continued to rise in the latter half of the past decade, due largely to the increased use of heroin and heroin with illicit fentanyl combinations.11 It is projected that in the future, as a result of efforts to reduce initial prescription opioid exposures, illicit opioid use will significantly decline. However, currently, perianesthesia nurses continue to encounter patients in the clinical setting who present with active or inactive OUD.
Perianesthesia nurses may encounter individuals with OUD due to circumstances unrelated to OUD. Those with OUD may require elective surgeries for procedures such as arthroplasty or hernia repair. Some will require procedures such as endoscopy or angioplasty. Others, especially those with a history of intravenous opioid use, may require surgery or procedures related to OUD. In some cases, emergency procedures are necessary as those who inject opioids are at increased risk for systemic infections, and may present with conditions such as spinal abscesses, orthopedic hardware or other implant infections, or endocarditis which may necessitate emergency diagnostic procedures and surgeries.
Individuals with active OUD presenting in the perianesthesia setting require an extensive history to determine the extent of opioid use as well as use of other substances including alcohol, prescription medications such as benzodiazepines, and other drugs such as marijuana, cocaine, and methamphetamine. The history, physical examination, and diagnostic studies are important to identify comorbidities, especially cardiac abnormalities, as injected opioids increase risks for infective endocarditis, and other substances, such as methamphetamine and cocaine may increase risks for cardiac disease. A thorough history is important to enable appropriate selection of the anesthetic plan. With a known history of active opioid use, it is important to plan for adequate perioperative analgesia in the postoperative period, including opioids to prevent withdrawal and multimodal analgesia, which may include regional analgesia, to provide safe and effective perioperative pain management.
Some individuals with OUD are in recovery and receiving treatment for the disorder with medication-assisted therapy (MAT). MAT includes the use of methadone (pure mu agonist opioid), buprenorphine (partial opioid agonist), or naltrexone (a mu antagonist).12 For a number of years, methadone, administered in a clinic setting often under direct observation, was the primary medication used in MAT. As a result of the 2016 Comprehensive Addiction and Recovery Act (CARA), treatment with buprenorphine has expanded due to increased availability of health care providers who can prescribe this medication in office-based practice settings. For many with OUD, this is a more socially acceptable form of treatment as the medication is obtained from a pharmacy and is usually taken privately, without the need for direct supervision. Injectable and implantable formulations of this medication are also available. Naltrexone, a medication that was primarily used for the treatment of alcohol use disorder (AUD), is also used in MAT for OUD. Availability of a parenteral formulation offers an advantage over daily oral use of naltrexone as the parenteral formulation is administered monthly and for some, provides a preferable treatment option.13
For those who require surgical procedures and are receiving MAT, a preoperative plan is necessary to assure appropriate anesthesia and perioperative pain management plans of care. The patient history should include assessment of opioid and other substance use history, history of MAT use, and comorbidities. The physical examination and diagnostic workup are important to identify comorbidities, including those related to prior opioid use. A preoperative 12-lead electrocardiogram (EKG) is important, even in younger people with OUD, to identify any arrhythmias as well as prolonged QTc intervals which may be associated with methadone use. A prolonged QTc interval may increase the patients risk of fatal arrhythmias such as torsades de pointes.14
Methadone is used in the treatment of OUD because it is a full mu-opioid agonist with a long half-life which permits a daily dose of methadone to be effective in reducing opioid craving, blocking euphoric effects of short-acting opioids, and preventing withdrawal for at least 24 hours.13,15,16 For those receiving methadone for treatment of OUD, it is necessary to confirm the dose with the treatment program, since methadone used for OUD does not appear on prescription drug monitoring programs. Some people in methadone treatment programs carry a card with the program information and current daily methadone dose. Preoperative instructions should include the recommendation to continue the daily methadone dose, even on the day of surgery. If admitted prior to surgery, or early in the morning of the procedure, the methadone dose should be administered in the perioperative setting.15
Unless contraindicated, methadone should be continued daily during hospitalization, and if oral medications cannot be administered, methadone is available in an intravenous formulation.15 Methadone is metabolized through the cytochrome P450 system, and although it can be safely used for those with renal or hepatic disease, it poses the risks for more drug-drug interactions than other opioids.14 Dosage adjustments may be necessary, and the assistance of a pharmacist may be necessary to minimize drug-drug interaction risks. It is unlikely that acute surgical pain will be adequately managed with the methadone dose used for MAT. Multimodal analgesia, including opioids, nonopioid analgesics, and nonpharmacologic approaches will likely be necessary to adequately control surgical pain. Contrary to misconceptions held by some patients, methadone will not block the effect of other mu-opioid agonists.
There are varied approaches to the management of buprenorphine in patients undergoing surgical procedures. Buprenorphine is a partial opioid agonist which has a ceiling effect for analgesia and possibly respiratory depression. Buprenorphine is administered sublingually at least once daily; other forms of administration include a weekly or monthly subcutaneous injection and implanted subcutaneous rods which release the medication over a 6-month period. If surgery is elective, some clinicians will wean sublingual buprenorphine off over 3 days and discontinue prior to surgery. Multimodal analgesia, including regional analgesia, nonopioid analgesics, nonpharmacologic approaches, and short-acting opioids are used until acute pain subsides, and then buprenorphine would be restarted.17
As clinicians have developed more experience with buprenorphine in the perianesthesia period, practices have evolved. Rather than stopping buprenorphine for elective or emergency surgeries, the practice of continuing buprenorphine during the perianesthesia period has emerged. If the preoperative dose is greater than 16 mg/d, the dose is reduced to 16 mg/d or lower, and short-acting opioids, nonopioid analgesics, co-analgesics, and regional analgesia may be used in a multimodal analgesia approach to surgical pain.18 Buprenorphine is returned to the preoperative dose when pain subsides. If buprenorphine is continued at doses greater than 16 mg/d, or if the weekly or monthly injection, or implanted rod device is used, high opioid doses and multimodal analgesics may be necessary to provide adequate pain relief due to the partial agonist effect of buprenorphine.15,18
Naltrexone is an opioid antagonist which can be delivered either orally (daily or three times weekly) or as a monthly intramuscular depot injection, therefore blocking both the euphoric and analgesic effects of opioids.15,19 With scheduled surgeries, oral naltrexone should be discontinued 72 hours prior to surgery and intramuscular injection discontinued 1 month prior to surgery. If emergency surgery is necessary, it may be necessary to use10–20 times the usual dose of opioids to effectively overcome the antagonism from naltrexone.13 As with buprenorphine, regional anesthesia, nonopioid analgesic strategies, and nonpharmacologic approaches should be considered to optimize pain relief.13
Nurses have an ethical responsibility to advocate for effective and safe postprocedural/postoperative pain management for all patients, including those who suffer from OUD.13 To optimize appropriate pain care, it is important, whenever possible, to identify patients preoperatively with OUD and discuss the need for a perioperative plan of care that considers the patient’s opioid tolerance, risks for inadequate analgesia, withdrawal, and respiratory depression. The plan of care should include appropriate adjustments for the patient’s use of MAT. If a patient is suspected of OUD, opioid antagonists such as naloxone should not be administered for respiratory depression unless absolutely necessary because withdrawal syndrome can be precipitated. No attempt should be made to induce opioid withdrawal of the patient who is actively dependent during the postanesthesia period.20 The challenges of opioid tolerance require consideration of a multimodal pain management plan that includes not only opioids (which may need to be higher than usual doses), but also nonopioid analgesics, co-analgesics, regional analgesia, and nonpharmacologic approaches.13 Preprocedure/preoperative interview should include discussion of pain relief goals and available analgesic treatment options.13
In addition to advocating for safe and effective pain management, it is important for perianesthesia nurses to assess patients for signs of opioid withdrawal. Signs of opioid withdrawal include mydriasis, piloerection, sweating, increase in pulse and blood pressure, diarrhea, abdominal cramping, and diffuse bone and muscle pain. The patient may also experience increased irritability, anxiety, and insomnia.21,22 Acute opiate withdrawal is not dangerous to life because it usually is not associated with seizures or delirium.21 Validated tools such as Objective Opioid Withdrawal Scale (OOWS), the Subjective Opioid Withdrawal Scale (SOWS), or the Clinical Opioid Withdrawal Scale (COWS) may be used to assess the severity of opioid withdrawal.23
Individuals who use opioids on a regular basis or those actively using heroin are at risk for withdrawal symptoms during the perioperative period and may require higher doses of opioid analgesics both to control the pain and to prevent withdrawal.23 Intravenous patient-controlled analgesia (PCA) may allow the patient to adequately control pain and minimize withdrawal.17
If withdrawal symptoms are severe, the use of alpha-2 agonists, such as clonidine, and symptomatic management through the use of anxiolytics, anticholinergics, and antidepressants may be helpful.21
Although a patient with OUD may be opioid tolerant, risks for respiratory depression still exist. Patients with OUD who are in recovery may be at greater risk if prescribers assume the history of OUD assures opioid tolerance and prescribe higher doses than would usually be prescribed.20 Following a period of recovery, tolerance to the respiratory depression effect may be reduced. It is difficult to predict, even with someone who is actively using opioids, what degree of tolerance is present. Additionally, cross-tolerance to opioids is incomplete. For example, if a person is misusing oxycodone prior to a procedure, and intravenous hydromorphone is used as the post-procedure analgesic, it is likely that the person will not have the same tolerance to the equianalgesic dose of hydromorphone as the oxycodone. For the person who is using heroin, equivalent doses of prescribed medications cannot be known as the degrees of heroin purity are unknown and other drugs, particularly fentanyl, are often cut into the heroin. Careful monitoring for signs of excessive sedation and respiratory is necessary, and it is prudent to use conservative doses initially but titrate up if pain is not controlled. Multimodal analgesia using pharmacologic and nonpharmacologic approaches is key to adequate pain relief and safety.
Another safety issue for patients in the postanesthesia setting is the concurrent administration of opioids and benzodiazepines. The concurrent use of these two classes of medications has been shown to increase the risk for respiratory depression.24 Prior to administering these medications, the perianesthesia nurse should assess which of the two types of medications is indicated, and if the patient has received both, assure close monitoring of sedation level and respiratory status. Knowledge of the half-lives of these medications is important in determining immediate postoperative risks as well as determining readiness for transfer out of the recovery area.
In summary, multimodal analgesia including nonsteroidal antiinflammatory drugs, acetaminophen, gabapentinoids, and local anesthetics is the foundation of acute pain management.13,25 The use of multimodal analgesia is especially important for individuals with histories of OUD, those on MAT, and those on chronic opioids who may not achieve effective pain management with opioid monotherapy.
Alcohol is the most widely misused substance in the United States. In 2019, more than 65 million Americans were reported to have engaged in recent binge alcohol use and AUD was reported in more than 14.5 million people.1 Alcohol misuse extends along a spectrum ranging from excessive use, to abuse, to alcohol dependence.26,27 According to the American Psychiatric Society, AUD falls under the Substance Use Disorder category and is associated with a problematic pattern of alcohol consumption that leads to significant impairments in many aspects of an individual’s life.2 AUD develops from multiple complex combinations of neural responses; genetic, social, environmental influences; and cognitive and behavioral processes.27 The complex interactions of alcohol with the brain’s circuitry in AUD affect reward, motivation, emotion, and other outcomes.
Alcohol acts upon numerous neurotransmitters which may explain, to some extent, its various behavioral presentations.28 Although categorized as a CNS depressant, alcohol has a biphasic effect which may be experienced differently by individuals. Generally, during the initial phase, alcohol acts as a stimulant and may result in euphoria and excitation progressing to stimulating and positive reinforcing effects until the second phase, when sedating and depressant effects are prevalent as levels slowly decrease.29
Chronic alcohol use impairs the immune defenses of the lower respiratory tract, can weaken the cough reflex, and increases risk for aspiration due to reduced oropharyngeal tone.30,31 In those with alcoholic liver disease, there may be alterations in drug metabolism as a result of induction of the cytochrome P450 system that could affect responses to anesthesia and analgesia. Those with acute intoxication during the perianesthesia period may have delayed emergence from anesthesia and obtunded airway reflexes.32
During the perianesthesia period, the absence of alcohol places patients with AUD at risk for alcohol withdrawal. The onset of symptoms associated with alcohol withdrawal syndrome (AWS) may present within 24 hours and withdrawal delirium may develop 2 to 3 days after the last intake of alcohol.33 Symptoms of AWS may range from mild to severe, and withdrawal is associated with increased risks for morbidity and mortality. The pathophysiology of withdrawal is complex and involves γ-aminobutyric acid (GABA)-mediated neurotransmission, dopamine, glutamate, and norepinephrine CNS feedback loops. Simply described, chronic alcohol use chronically stimulates inhibitory GABA-mediated neurotransmission and depresses the sensitivity of the autonomic nervous system, resulting in receptor upregulation.34 When alcohol is suddenly withdrawn, there is a lack of inhibition of the neurotransmitters and CNS neurotransmission is no longer opposed. This may result in anxiety, hyperreflexia, tremor, sleep disturbances, and reduced seizure threshold. Other signs include diaphoresis, fever, tachycardia, and hypertension.35 Delirium tremens (DT) is the most serious complication of AWS, and it presents with alterations in level of consciousness, cognitive deficits, confusion, vivid hallucinations, and hypertension 2 to 5 days after the last alcohol intake.33,35 If unrecognized and inadequately addressed, acute alcohol withdrawal may result in fatal arrhythmias, seizures, severe electrolyte abnormalities, dehydration, seizures, multiorgan failure, and cardiopulmonary arrest.33 DTs are associated with a mortality rate of approximately 1%–4% due to comorbidities and delayed treatment.35
Excessive alcohol use has significant effects on the gastrointestinal system. It can lead to liver cirrhosis, which causes abnormal hepatic circulation. Those with cirrhosis may have coagulopathies, gastrointestinal bleeding from esophageal varices, and renal insufficiency, and they may develop hepatorenal syndrome.15 Hypoxia due to hepatopulmonary syndrome and pulmonary hypertension may develop. Patients with cirrhosis are high surgical risks. Some anesthetic agents may decrease hepatic blood flow, which can further compromise the hepatic system. Mortality is related to the severity of cirrhosis and is often due to hemorrhage, sepsis, and hepatorenal syndrome.15
In the perianesthesia setting, a patient history should include assessment for active and past alcohol use and misuse, and the potential for withdrawal syndrome. If it is disclosed during the history that the patient is in recovery, it is important to determine if the patient is being treated with naltrexone. Naltrexone has been found to reduce compulsive drinking and reduce relapse frequency. It blocks opioid receptors within the mesolimbic dopamine system, thereby reducing rewarding effects of alcohol and cravings, and supports abstinence.29
As with treatment for OUD, for scheduled procedures, oral naltrexone should be discontinued 72 hours prior to surgery, and for naltrexone administered by monthly injection, surgery should be delayed, if possible, until at least 1 month after the last injection. If emergency surgery is required, the use of multimodal analgesia is necessary, including nonpharmacologic approaches, and it can be anticipated that much higher doses of opioids would be needed to effectively overcome the antagonism from naltrexone.
Perioperative nurses play an important role in the recognition of alcohol withdrawal risks and assessment for signs and symptoms of withdrawal. When taking the patient history, it is important to determine the timing of the last use of alcohol to enable prompt recognition of AWS and initiate interventions to reduce signs and symptoms. Although life-threatening DTs may not be of immediate concern in the perianesthesia setting, some patients may be in this window of time, and thus the perianesthesia nurse should recognize and intervene to treat this serious condition.
Treatment of AWS addresses symptomatic management and careful assessment for effectiveness and possible progression. The main objective is to address agitation, prevent seizures, and support the cardiopulmonary system.33 Delirium and disorientation require frequent reorientation to time, person, and surroundings. External stimuli should be reduced as much as possible, and normalization of day and night, light and dark should be attempted. It is necessary to assure adequate hydration, monitor intake and output, and check laboratory results to assure electrolyte balance.33 The revised Clinical Institute Withdrawal Assessment of Alcohol Scale (CIWA-aR) is a useful tool to assess the extent of withdrawal and guide treatment interventions. The CIWA-aR–based regimen is used to guide symptom-triggered treatment and has been shown to have greater effectiveness than fixed-schedule treatment approaches.36 Benzodiazepines such as diazepam, chlordiazepoxide, and lorazepam are the initial choices in symptom-triggered treatment of AWS, and are also helpful in preventing seizures and delirium. Treatment may also include use of anticonvulsants, barbiturates, beta blockers such as propranolol, or alpha-adrenergic agents such as clonidine to reduce autonomic manifestations.36 Thiamine replacement and multivitamins are also often prescribed.33
Medications in the sedative-hypnotic class include barbiturates, benzodiazepines, nonbenzodiazepine sedative-hypnotics, also referred to as Z-drugs (sleep aids such as zolpidem), muscle relaxants, and anticonvulsant medications, all of which decrease CNS activity. These medications act on GABA receptors to provide anxiolysis, anticonvulsant, amnestic, and sedative effects. Although barbiturates were the first preparations in this class, the use of barbiturates has markedly declined because they have been replaced by benzodiazepines and serotonin reuptake inhibitors with better safety profiles.34
The safety of benzodiazepines and Z-drug use in surgical patients is not well known, yet the perianesthesia period poses significant risks for interactions of these medications with opioids and anesthetic medications.37 The Beers Criteria, published by the American Geriatric Society, recommends that hypnotic medications, including benzodiazepines and Z-drugs, should be avoided in older adults due to safety concerns.38 For older adults, it is recommended to taper or discontinue benzodiazepine use to reduce postoperative delirium risks.37
The most significant complication of barbiturate or benzodiazepine abuse is respiratory depression, and that risk is increased when sedatives are used along with alcohol or opioids.5 Sedative-hypnotic use can lead to advancing sedation, declining levels of consciousness, coma, and loss of airway protective reflexes.39 Long-term benzodiazepine use is associated with dependence, memory impairment, decreased coordination, and increased fall risk. When benzodiazepines have been used consistently, if discontinued abruptly, there is risk for life-threatening acute withdrawal. Withdrawal may be manifested as grand mal seizures, confusion, and delirium which may present 24 to 48 hours after discontinuation. Patients who intermittently use benzodiazepines may also experience withdrawal effects. The perioperative period is not an appropriate time to discontinue benzodiazepine use as these medications should be gradually tapered, with use of other medications to alleviate the discomfort of the taper.
Z-drugs are sedative-hypnotics with short half-lives that are prescribed for the treatment of insomnia.40 This class of medication was thought to offer a safer alternative to barbiturates and benzodiazepines as reduced risks for tolerance and dependence were expected. However, these medications have been associated with similar risks for respiratory depression, abuse, and withdrawal syndromes. Like benzodiazepines, the perioperative period is not the appropriate time to discontinue these medications, but instead they should be gradually tapered.
The perianesthesia nurse must assess patients for signs of benzodiazepine, Z-drug, and barbiturate overdose as well as withdrawal. Overdose symptoms are similar to those seen in patients with alcohol abuse such as incoordination and speech slurring that can progress to coma. Managing overdose first involves airway protection. Flumazenil (Romazicon), a benzodiazepine receptor antagonist, is the reversal agent for benzodiazepine overdose41 and has also been shown to reverse sedation from the Z-drugs. In the case of barbiturate overdose, optimal supportive care is necessary, including intubation and mechanical ventilation if necessary, as flumazenil will not antagonize barbiturates.42
Flumazenil must be used with caution in patients who are benzodiazepine (or Z-drug) dependent as reversal of benzodiazepines is associated with precipitation of the withdrawal syndrome, with potential development of seizures and cardiac dysrhythmias.41 Signs of withdrawal can include the constellation of symptoms seen in alcohol withdrawal: tachycardia, hypertension, anxiety, insomnia, diarrhea, nausea, and, more seriously, delirium and seizures. Benzodiazepine tapers usually take 4 to 8 weeks to accomplish discontinuation without withdrawal symptoms. Ideally, benzodiazepine discontinuation should not take place in the perioperative setting. If benzodiazepines are abruptly discontinued or tapered too rapidly, the use of diazepam along with medications such as antidepressants, mood stabilizers, nonbenzodiazepine anxiolytics, gabapentin or pregabalin, and beta blockers are often used to alleviate withdrawal symptoms.41,43
CNS sympathomimetics include natural alkaloids such as cocaine, ephedra, and khat as well as synthetic compounds such as “bath salts,” methamphetamine, methylphenidate, and amphetamines. These stimulants inhibit the reuptake of the catecholamines: norepinephrine and dopamine.44–46 Effects of stimulant use are dependent on the drug and dose. All can cause increased alertness and reduced fatigue. Prescription stimulants such as methylphenidate and amphetamines, ephedra (ephedrine), and, with restricted use, cocaine, have indications for medical uses, but are also substances that are misused and abused. Other products such as coffee and khat, derived from a plant from in East Africa, have socially acceptable use for their stimulant properties.44 Synthetic illicit or over-the-counter stimulant preparations known as “bath salts” have had a dramatic rise in abuse.46
Although cocaine is used legally as a topical or local anesthetic for nasal procedures, it is well known as a drug of misuse in the form of smoking, inhalation, or injection. Cocaine can contain many contaminants that can cause side effects. Morbidity and mortality are attributed to the cocaine-associated risks of myocardial ischemia (MI), coronary artery vasospasm, uncontrolled hypertension, tachyarrhythmias, arterial dissections, and intracranial bleeds. Postoperative agitation is associated with cocaine use.45
Ephedra or the synthetic ephedrine is a sympathomimetic agent which indirectly causes elevated norepinephrine concentration. It is used medically for treatment of nocturnal enuresis and hypotension associated with anesthesia and spinal cord injury. It is also used in common cold products, dietary aids, and some herbal treatments. The CNS stimulant effects of ephedra increase risk for nonmedical use and abuse of these products and may lead to morbidity and mortality.45
Methamphetamine, a substance originally used in the treatment of obesity and attention-deficit disorder, has become a highly addictive recreational drug which is widely abused for its stimulant properties.47 It is easily produced in home laboratories using over-the-counter pseudoephedrine, thus requiring strict control over pseudoephedrine product purchases from pharmacies.48 Known as meth, crystal, chalk, or ice, it can be ingested, smoked, snorted, or injected and results in immediate and intense euphoria. Methamphetamine use is associated with significant neurologic and other physical consequences.47
CNS stimulant abuse can cause psychosis, hallucinations, restlessness, and agitation. Physiologic signs can include changes in temperature regulation, pupil dilation, tachycardia, cardiac arrhythmias, diaphoresis, nausea, and anxiety. These preparations in higher doses can cause neurologic and cardiovascular complications.47 Cocaine withdrawal, and withdrawal from other stimulants, is associated with depression, tiredness, insomnia, unpleasant dreams, increased appetite, decreased cognition, and movement. Unlike alcohol or benzodiazepines, stimulant withdrawal is not life-threatening.48
Anesthetic implications of cocaine or other stimulants are related to the potential for cardiovascular complications such as arrhythmias, hypertension, and MI.49 In the case of severe hypertension, there is controversy related to the use of beta blockers as there is risk of increased blood pressure from unopposed alpha activity. If a beta blocker is necessary, esmolol may be the preferred medication as it results in less hypertension from unopposed alpha activity, has a short half-life, and is easily titrated.50 Acute amphetamine use may result in hyperthermia and increased anesthetic requirements. However, chronic amphetamine use may reduce anesthetic requirements and cause hypotension due to catecholamine depletion, therefore necessitating use of direct-acting vasopressors.51 The potential for catecholamine depletion with acute cocaine intoxication or other stimulant overdose may also contraindicate the perioperative use of ketamine.52
In the perianesthesia setting, the nurse assesses for presurgical risks, including a history of stimulant use, and in the postanesthesia area, the nurse assesses the patient’s responses throughout recovery and intervenes as necessary. Cocaine (and possibly other CNS stimulants) have various adverse effects on the cardiovascular system, including MI, aortic dissection, heart failure and cardiomyopathies, stroke, excessive hypertension, chest pain, and arrhythmias.53 These cocaine-related complications may be the reason for the patient’s surgical procedure, or they may develop during the perioperative period. The perianesthesia nurse’s assessment skills are essential to identify complications and initiate immediate medical interventions. Skill in neurologic assessment is necessary to identify signs of stroke. Due to an increased risk of arrhythmias and MI, any reports of palpitation, light-headedness, chest pain, or other signs or symptoms of MI should be immediately assessed and reported to initiate a cardiac workup including serial troponins and 12-lead EKG monitoring. Most of these effects occur in the first 3 hours after cocaine ingestion and may be increased in those using multiple stimulant preparations. Patients should be monitored for severe hypertension to prevent cerebral hemorrhage. Tachyarrhythmia can occur, and treatment will target the underlying problem.
Cannabis sativa is a widely used plant, of which tetrahydrocannabinol (THC) is the most active substance.54 The discovery of endogenous cannabinoid receptors has changed the direction of research, and more potential uses for cannabis have been discovered. Marijuana, the generic term applied to the hemp plants, can be ingested, smoked, or vaporized.55 As of 2020, marijuana or the use of cannabidiol extract was legal in over 50 states and territories in the United States for “medicinal use,” often for cancer or chronic illnesses. “Recreational use” is now also legal in a number of states and the District of Columbia.56 Legalization of marijuana is expected to increase and, at some point, patients who use marijuana may regularly present in the clinical setting.
Acute marijuana use can result in a variety of effects. For some, marijuana is used for a sensation of euphoria and relaxation, although some experience paranoia and panic. It is associated with decreased cognitive function, perception, memory, reaction time, and impaired memory. Sympathetic nervous system activity is increased and parasympathetic activity is reduced, resulting in cardiovascular effects which include tachycardia, orthostatic hypotension, and peripheral vascular dilation.54,57
Chronic cannabis use is associated with an increased risk of anxiety, depression, and psychosis. When chronic marijuana is smoked, it can cause lung deposits and decreased pulmonary function. Carcinogen exposure may occur with smoking of marijuana in unfiltered papers, and with vaping cannabis oil which contains irritant compounds.57 The chronic use of high doses of recreational and medical marijuana have been associated with severe cardiovascular problems such as serious arrhythmias, coronary spasm, sudden death, and stroke.57 Ischemic stroke and transient ischemic attacks have been reported in patients with heavy, chronic use. Cannabis or cannabinoid use has also been linked to a reduction in body temperature.54 Cannabinoid hyperemesis syndrome is a paradoxical hyperemetic effect that develops in some who chronically use cannabis and cannabinoids. It is characterized by a cyclic pattern of severe nausea, vomiting, and abdominal pain, which is refractory to usual antiemetics, and rapidly improves when cannabis use is stopped.57 With regular use, tolerance to the effects of marijuana can develop. Withdrawal symptoms from regular marijuana use include irritability, anxiety, insomnia, diaphoresis, tremors, nausea, vomiting, diarrhea, and abdominal pain.51
Synthetic cannabinoid products such as K2, K3, Spice, and Dream are abused by smoking or vaporization. Many different synthetic compounds have been produced and it may be difficult to identify the ingredients in these products. The vast majority of synthetic cannabinoids have never been studied in research trials, and the effects are confounded by the use of more than one synthetic cannabinoid as well as other substances in a single product. Like marijuana, these cannabis substitutes bind to the cannabinoid receptors. These potent synthetics can cause significant CNS, cardiovascular, pulmonary, gastrointestinal, renal, and psychiatric side effects, including myocardial infarction and renal injury.58
In the perianesthesia care setting, patients who regularly use marijuana exhibit few adverse effects related to the drug use because of marijuana’s short half-life. The main effect related to acute use is sedation, and with chronic use, respiratory issues, similar to tobacco use, are possible. The nurse should assess for pulmonary changes secondary to chronic irritation by smoke inhalation.54 In addition, if the patient exhibits signs of withdrawal from chronic use, the nurse should alert the prescriber so that appropriate symptomatic treatment can be administered.
During the postoperative period, the nurse should anticipate an increase in the incidence and severity of shivering related to perioperative hypothermia. The need for use of warming blankets should be addressed to normalize body temperature during Phase I postanesthesia care.54 Shivering can increase metabolic demands, and in vulnerable patients, the increased demand may contribute to negative cardiac effects such as increased oxygen consumption, tachycardia, arrhythmias, and MI.54 When giving postoperative instructions, patients who use recreational marijuana should be advised to avoid use during the postoperative period due to potential drug-drug interactions when marijuana is used along with opioids. Those who receive medical marijuana should be advised to discuss the potential postoperative drug-drug interactions with their prescriber.
If the perianesthesia nurse suspects use of synthetic cannabinoid products, the patient should be monitored for tachycardia, hypokalemia, and renal changes. Because the components of the substances are unknown, if a patient has been using these products, it is important to monitor and anticipate adverse effects that may compromise the patient’s condition.
Many chemically diverse hallucinogens exist. Some are derived from plants and mushrooms, while others are synthetically developed. Hallucinogens include LSD, 3,4-methylenedioxymethamphetamine (MDMA), dimethyltryptamine (DMT), mescaline (peyote), and psilocybin.59 These drugs have different mechanisms of action with similar effects. Hallucinogens primarily affect the 5-HT2A receptors, resulting in visual hallucinations, rather than dissociation or decreased reality testing.60
LSD is a serotonergic hallucinogen that received research interest in the 1950s and 1960s to enhance creativity, for spiritual experiences, and in some cases for psychotherapeutic interventions. This research contributed to the understanding of the neurochemistry of serotonin and its role in mental functioning.61 LSD became criminalized and, along with other hallucinogens, is now used recreationally. LSD is ingested orally, and its major effects occur in a dose-related manner. Moderate doses of the drug cause euphoria, marked sensory distortion (including heightened awareness of sensory stimuli), and alterations in thinking and time processing.61 Large doses of LSD may lead to frightening hallucinations and a distorted body image, commonly known as a bad trip. People under the influence will have dilated pupils and may have increased heart rates and blood pressure. Peak effects of LSD occur between 1.5 and 2.5 hours after ingestion, and psychologic effects can last 6 to 11 hours.61 Tolerance to the psychologic and autonomic effects occurs after a few doses. Although deaths have been associated with LSD use, the deaths are attributed to dangerous behaviors associated with the psychedelic effects, not the drug. LSD is considered nontoxic and physiologically safe when used at moderate doses.62
The effects of other hallucinogens vary. When DMT is smoked or injected intravenously, the onset of effects occurs within 30 to 60 seconds, peaks within 3 minutes, and lasts 20 to 30 minutes. When ingested as an oral tea, it has an onset of 60 minutes, peak of an hour, and duration of 3 to 4 hours.61 Lower doses cause vegetative effects, while higher doses result in hallucinatory effects.61 DMT can produce increases in blood pressure and heart rate and other sympathomimetic effects. No lethal intoxications have been documented.
Mescaline is the principal hallucinogenic compound derived from the peyote cactus, and its popularity as a recreational drug is limited. Oral mescaline is rapidly absorbed and has an onset of effect within 45 minutes after ingestion. It peaks in 2 to 4 hours, and the effect lasts for 4 to 6 hours. Effects include mydriasis, dizziness, diarrhea, headache, nausea, vomiting, tremors, chills, and weakness. Mescaline intoxication produces a dream-like state with euphoria or dysphoria, altered perceptions of time, space, color, sound, and shapes. Complex hallucinations may also occur. There are no known physical complications or dependency syndromes associated with mescaline use.63
MDMA, the active substance in ecstasy, is under investigation as an adjunct to psychotherapy for the treatment of post-traumatic stress disorder (PTSD). MDMA raises cortisol levels, thereby increasing energy.63 MDMA is used as a recreational drug for its amphetamine-like and hallucinogenic effects. MDMA may cause pleasant visual hallucinations, although some will have marked anxiety and panic attacks.
Although risks associated with MDMA use were thought to be lower than risks with other recreational drugs, known complications are associated with mixing of other drugs into the MDMA, or substitution of other drugs for what is supposed to be MDMA. It is used in overnight (rave) parties and may be associated with overexertion (dancing) and dehydration leading to hyperpyrexia, rhabdomyolysis, and heat stroke. However, others may drink excessive amounts of water and develop hyponatremia, cerebral edema, seizures, and coma.64 MDMA can increase blood pressure and heart rate. High-dose toxicity can cause tachycardia, hypertension, and hyperthermia that are life-threatening. Individuals under the influence may be diaphoretic and have jaw clenching.
MDMA has a duration of action of 3 to 6 hours, and it may take as long as 3 days for withdrawal symptoms to develop. Withdrawal symptoms include fatigue, anxiety, irritability, insomnia, decreased appetite, poor concentration, paranoia, and depression.64 MDMA use should be avoided in those at increased risk for malignant hyperthermia.64 There are no significant drug-drug interactions between hallucinogens and medications commonly used in the perioperative setting.
If the patient is suspected of being under the influence of a hallucinogen, the perianesthesia nurse should observe for effects such as tachycardia and increased blood pressure. In rare cases, hyperthermia may be present and require treatment. Chronic use of MDMA may result in depressive symptoms, and problems with memory, sleep, and attention.64 The nurse may have to provide support for the individual experiencing negative psychologic effects from the hallucinogen. Pharmacologic agents to counteract these effects include benzodiazepines such as lorazepam or diazepam, antidepressants, or, in refractory cases, haloperidol.64
PCP, ketamine, and dextromethorphan (DXT) are the most commonly abused dissociatives that have some effects similar to hallucinogens. Dissociatives are distinguished from hallucinogens because they affect glutamic acid N-methyl-D-aspartate receptors. PCP was initially used in anesthesia, but it was discontinued as an anesthetic because it produced postoperative dysphoria and hallucinations.65 People under the influence of PCP can experience confusion, delirium, and psychosis. When ingested in large doses, physiologic effects can be life-threatening and include hypertension, cardiac failure, stroke, rhabdomyolysis, renal failure, and coma.66
Ketamine, a dissociative anesthetic, is used for general anesthesia, moderate sedation, and analgesia (in subanesthetic doses), and it is currently receiving research attention for its use as an antidepressant and as a rapid-acting medication to reduce suicidal ideation. Ketamine has gained popularity as a recreational drug and is known as “K,” “special K,” or “super K.” When injected, ketamine has a quick onset and duration of 10 to 20 minutes. Those under the influence of ketamine may experience hallucinations.63 The toxic effects can be similar to PCP but are usually less severe.66
DXT, an over-the-counter cough product, can produce CNS effects at higher doses. DXT is ingested and peak effects are in about 2.5 hours, with effects up to 6 hours. At higher doses, DXT may cause hypertension, lethargy, ataxia, and hyperexcitability.60,63
The perianesthesia nurse is unlikely to have much contact with a patient under the influence of recreational dissociative use unless the patient is admitted for an emergency surgical intervention. If perianesthesia care is required, the nurse must monitor and address signs of sympathetic activation such as tachycardia and elevated blood pressure. If the patient is experiencing hallucinations, the nursing care is similar to those under the effect of hallucinogens.
Inhalants, breathable chemicals that can be self-administered as vapors or gases, have been abused for a long period of time and were first used as intoxicants over 200 years ago.67 Use of inhalants is mostly seen in the teenage population (12–19 years old) and every year, more than 750,000 people over the age of 12 use inhalants for the first time.67 Abused inhalants are divided into three classes: (1) volatile alkyl nitrates; (2) nitrous oxide; and (3) volatile solvents, fuels, and anesthetics.67
Volatile alkyl nitrates are cyclohexyl nitrite (room deodorizers and video head cleaners) and amyl nitrite (angina agent). These products cause vasodilation and venous pooling, and can cause syncope and tumescence, which makes them desirable as sexual aids.67 Nitrous oxide is used in cylinders for anesthesia and is also found in food product propellants such as whipped cream chargers. Nitrous oxide produces a feeling of euphoria and intoxication, and excessive use can lead to anoxia.67 The third class (solvents, fuels, and anesthetics) is a diverse group of substances including adhesives, paints, varnish removers, and gases. It is possible that many of these commercial products have similar properties as subanesthetic concentrations of volatile anesthetics such as isoflurane and sevoflurane. The inhalation of these commercial products, as well as the illicit use of the volatile anesthetics, produce rapid-onset, short-acting alcohol-like intoxication.67
Inhalants cause an intoxicating effect when they are inhaled through the nose or mouth into the lungs. The three types of inhalants have different absorption characteristics, but for all, the effect and elimination are very rapid once the inhalation of the agent has ended. For this reason, abuse of inhalants is often undetected. Inhalants’ effects can be similar to the effects of alcohol, depressants, or hallucinogens. Generally, the effects are shorter than other drugs of abuse, but these products can cause seizures. Toxicity is substance dependent due to the wide array of inhalants available and used illicitly. Overdose generally occurs when the individual continues to be exposed to the inhalant after losing consciousness. Inhalants may cause neurotoxicity, cardiotoxicity, hepatotoxicity, and renal damage, and some inhalants are known carcinogens.67 Those who use inhalants on a regular basis may have facial rash, eyes/nose irritation, and inflammation in the respiratory system secondary to the exposure.67
The perianesthesia nurse may not routinely come in contact with the patient under the influence of illicit volatile substance use. However, those who work in the pediatric perianesthesia care unit may have contact with adolescents who abuse these substances. Patients should be evaluated for possible use of these substances, especially when there are signs of possible use such as ear and nose irritation, facial rashes, unexplained cough, or abnormalities in hepatic or renal laboratory tests. If there is liver dysfunction, the patient will require observation for a prolonged effect of both anesthetics and analgesics. If the perianesthesia nurse suspects that a patient is chronically using inhalants, the anesthesia care provider should be notified to adjust the analgesic regimen and arrange for follow-up referrals.
A diverse group of drugs and has been used in a younger subculture for late night dance events known as “raves.” Drugs in this class include the hallucinogen/stimulant MDMA (or ecstasy), gamma hydroxybutyrate (GHB), and flunitrazepam (Rohypnol), which are CNS depressants.
The problems associated with MDMA are similar to those found with the use of hallucinogens and amphetamines, which were discussed previously. High-dose toxicity can cause tachycardia, hypertension, and hyperthermia that are life-threatening. Paranoia and anxiety can also develop. Treatment for anxiety includes benzodiazepines, and for acute cardiovascular toxicity, treatment is an adrenergic antagonist with a vasodilator.66
GHB (liquid ecstasy) is popular because of its aphrodisiac and disinhibitory effects. After oral ingestion, it has a short duration of action of 2 to 4 hours. There is no antidote. At higher doses, it can cause somnolence, confusion and hallucinations, bradycardia, hypotension, hypothermia, seizures, and coma.66,68
Flunitrazepam (Rohypnol), also known as “roofies,” is an illegal benzodiazepine associated with date rape. Effects of the drug include anterograde amnesia, bradycardia, hypotension, and respiratory depression. If severe respiratory or cardiac effects occur, the benzodiazepine agonist flumazenil can be used.66,68
It is unlikely that the perianesthesia nurse will have contact with individuals under the influence of these drugs unless the patient requires emergency surgical intervention. If the perianesthesia nurse is caring for the patient under the influence of club drug and date rape drugs, the first priority is supportive care to protect the cardiorespiratory system, especially in the case of overdose. For patients with hyperactivity, agitation, anxiety, hallucinations, and bizarre or reckless behavior, it is important to assure close observation and a quiet environment with minimal sensory stimulation. Oversedation secondary to flunitrazepam should be treated like oversedation secondary to benzodiazepine use.68 Withdrawal symptoms from these substances can usually be managed with benzodiazepines.66,68
Substance use in the United States is an increasing concern for all health care providers. SUDs may affect individuals of all ages and socioeconomic backgrounds. The purpose of this chapter is to provide the perianesthesia nurse with an overview of the many drugs and substances of misuse and abuse that can affect care of patients in the perioperative setting. Many more substances than those described within this chapter may be misused. Combinations of different substances may be misused and newer synthetic formulations are regularly emerging, posing additional risks for individuals and challenges for health care providers. Perianesthesia nurses need to be informed and vigilant to the possibilities that patients they are caring for may be under the influence of, or withdrawing from, substances or drugs. Working with the multidisciplinary team, perianesthesia nurses may intervene to optimize patient safety, surgical outcomes, and patient comfort. See Evidence-Based Practice.
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