Absorption

The degree and rate of absorption are based on factors such as the child’s age, health status, and weight, and the route of administration. As children grow and develop, the absorption of medications generally becomes more effective; therefore, less developed absorption in neonates and infants must be considered in dosage and administration. In contrast, during the adolescent years, poor nutritional habits, changes in physical maturity, and hormonal differences may cause slowing of medication absorption. Hydration status, presence of underlying disease, and gastrointestinal (GI) disorders in the child may be significant factors in the absorption of medications.

Drug absorption is initially influenced by the route of administration. For oral medication, conditions in the stomach and intestine, such as gastric acidity, gastric emptying, gastric motility, GI surface area, enzyme levels, and intestinal flora, all mediate drug absorption. Lack of maturation of the GI tract is most pronounced in infancy, making the neonatal and infancy periods those most affected by changes in absorption physiology. Gastric pH is alkaline at birth; acid production begins in the neonatal period. Gastric pH may not reach adult acidity until age 1 to 3 years. A low pH or acidic environment favors acidic drug absorption, whereas a high pH or alkaline environment favors basic drug formulations; therefore, differences in pH may hinder or enhance the absorption of medications. Gastric emptying is generally prolonged in neonates and infants but increases as the child grows. Nurses should be aware that delayed emptying in children reduces the peak serum concentrations of medications.

Varying transit times through the GI system may also hinder or enhance absorption of oral medications, depending on the usual site of chemical absorption. For this reason, feeding methods may affect infant absorption; for example, breastfed infants have faster gastric emptying than formula-fed infants. Frequent infant feedings also affect GI transit times. The more frequent the feedings, the less time the food is in contact with the gastric or intestinal lining.

Irregular peristalsis associated with immaturity or with symptoms of vomiting or diarrhea decreases the absorption time available for medications. In contrast, many pediatric medications actually cause diarrhea, which again bears on absorption rates. In younger infants and children, the GI surface area is greater than in adults, allowing for more absorptive area in the stomach and intestines. This difference in pediatric anatomy and physiology may affect the speed and effectiveness of absorption, especially in the small intestine. Immature enzyme function may also affect drug absorption; for example, low lipase levels deter the absorption of lipid-soluble medications. Microorganism colonization of the intestine, as it changes with pH and flora, creates different environments that may change medication absorption. All of these factors must be considered when assessing the effectiveness of medications administered by the oral route.

For medications administered via the subcutaneous (subQ) or intramuscular (IM) routes, absorption occurs at the tissue level. The level of peripheral perfusion and effectiveness of circulation affects the medication’s ability to be absorbed. Conditions that alter perfusion (e.g., dehydration, cold temperatures, alterations in cardiac status) may impede absorption of medications in the tissues. Intravenous (IV) medications are administered directly into the bloodstream and are immediately absorbed and distributed.

Topical medications—those absorbed through the skin—may be altered by the condition of the skin tissue. Because children’s skin is thinner and more porous, absorption may be enhanced. The skin surface area for children is proportionately higher than for adults such that many medications are more readily absorbed than in adults.

Distribution

The distribution of medication throughout the body of a child is affected by factors such as body fluid composition, body tissue composition, protein-binding capability, and effectiveness of various barriers to medication transport. In neonates and young infants, the human body is about 70% water. (As the child grows, this percentage decreases to 50% to 60%.) This increased body fluid proportion in the very young allows for a greater volume of fluid in which to distribute medication and a lower concentration of the drug. Until about age 2 years, the pediatric patient requires higher doses of water-soluble medications to achieve therapeutic levels. Younger patients also have higher levels of extracellular fluids, which increase the tendency for children to become dehydrated and change the distribution of water-soluble medications.

Neonates and young infants tend to have less body fat than older children. The difference means that this age group requires less fat-soluble medications than adults, because fat-soluble drugs saturate fat tissue before acting on body tissues. Less fat available for saturation creates a need for less medication.

Drugs become bound to circulating plasma proteins in the body. Only drugs that are free, or unbound, are available to cross the cell membrane and exert an effect. Infants and neonates have less albumin than older patients and fewer protein receptor sites available for binding with medication; this allows medication to be more available for use and dictates a decrease in the dosage needed in young patients to produce the same therapeutic effect. Greater quantities of circulating drugs caused by reduced plasma proteins increase the propensity for adverse or toxic reactions in infants younger than 1 year. In neonates, high bilirubin levels may pose a health risk related to the administration of medications. Bilirubin molecules may bind with plasma protein sites, making the sites unavailable to medications and allowing large amounts of drug to remain free and available for effect. If neonatal medications are prescribed, dosages must be decreased and closely monitored to both ensure therapeutic effectiveness and avoid adverse effects.

Anatomic barriers to medication distribution, such as the skin or the blood-brain barrier, must be considered when drugs are administered to pediatric patients. The skin is more absorptive in young children, as previously described, and allows rapid distribution of medication. Infants’ blood-brain barriers are relatively immature, allowing medications to pass easily into nervous system tissue and increasing the likelihood for toxicity. As a child matures, both of these barriers become more impervious to medication, and dosages must be titrated accordingly.

Metabolism

The metabolism of medications depends greatly on the maturation level of the pediatric patient and varies from child to child. Metabolism is carried out primarily in the liver, with the kidneys and lungs playing a small part in the metabolic stage. For most children younger than 2 years, sustained decreases in levels of hepatic enzymes result in slower metabolism of medications. Hepatic metabolic activity is lower in neonates; infant hepatic function matures at age 1 to 2 months. This issue, as with other pharmacokinetic factors, reinforces the importance of the nurse evaluating therapeutic effects and monitoring adverse effects of medications.

Children inherently have higher metabolic rates than adults, causing metabolism to occur more rapidly. This may necessitate a higher medication requirement than for adults. For example, pain medication for children may require increased dosages or decreased durations between dosages. After oral medications are absorbed, they are metabolized in the liver. This phenomenon, called the first-pass effect, causes drugs administered by the oral route and absorbed via the GI tract to undergo some metabolism in the hepatocytes in the liver before they are made available to the body tissues. For select medications, when the oral route is ordered, the first-pass effect must be considered in the calculation of dosages. Some medications are administered by the rectal route to avoid the hepatic first-pass effect.

Excretion

The excretion of medications occurs in the kidneys, intestines, lungs, sweat glands, salivary glands, and mammary glands, with the kidneys providing the most elimination. Before about age 9 months, infants experience a reduction in the elimination capacity of the kidneys because of decreased renal blood flow, decreased glomerular filtration rate, and reduced renal tubular function. (At the onset of adolescence, renal tubular function is again decreased.) Because medications are excreted more slowly as a result of this decreased renal function, they can accumulate and may reach toxic levels. Water is needed for the effective excretion of medication, so patients must be evaluated for dehydration. Nurses need to carefully monitor renal function, urine flow, and medication effectiveness to evaluate the impact of medication excretion on patient status.

Pediatric Medication Dosing and Monitoring

Because of the changes in pharmacokinetics and pharmacodynamics inherent in pediatric patients, a key nursing role is to monitor the patient for therapeutic effect and adverse reactions. The processes described earlier in the chapter may be measured using plasma or serum drug levels, which indicate the amount of medication in a patient’s body. Close monitoring of serum drug levels can assist in establishing appropriate dosages, schedules, and routes of administration. Monitoring can also assist in indicating when the dose is too high (toxic) or too low (not therapeutic). The therapeutic ranges established for many drug levels are based on adult studies, so it is important for the nurse to assess pediatric patients in conjunction with monitoring blood levels. Serum blood levels are not available for all medications, so patient clinical responses to medications are especially important when monitoring drug effects.

The calculation of pediatric dosages is based in part on FDA recommendations, approved protocols, research studies, and provider experience. Most medications are ordered based on the child’s weight in kilograms; therefore, a “dose per unit of weight” calculation is required. In caring for children of higher weights, dosages are, at times, calculated on lean body mass to ensure an appropriate dose. Some medications, such as chemotherapies, are prescribed based on body surface area (BSA, or mg/m²). Dosing must also consider the individual child’s status, including age, organ function, health, and route of administration.

Pediatric Medication Administration

A key issue with pediatric medication administration is confirming the identification of the patient who is to receive the dose. Using the patient’s identification wristband in inpatient settings is the most effective method to ensure patient identity; outpatient and other settings pose a greater challenge. Children may not be able to communicate or want to divulge their names. To ensure safe medication administration, a reliable method to identify patients for each setting must be created. Automated computerized and bar-coding systems are especially effective in ensuring safe medication administration in the pediatric population. It is the nurse’s responsibility to check medication dosages and ensure that they are safe and effective.

Developmental and cognitive differences must always be considered when administering medication to children. It is important for the nurse to differentiate the child’s developmental age from the chronologic age, because this difference has an impact on the child’s response and responsiveness to medication. The pediatric patient’s ability to understand the process, the reasons for medication, and the need to cooperate with the procedure must always figure prominently in the pediatric nurse’s plan of care. The child’s temperament may influence understanding and level of cooperation. Especially in pediatric nursing, the concept of family-centered care is essential to ensuring safe care during and after health care intervention. Teaching is directed toward family caregivers and patients commensurate with the cognitive level of the child. When possible, family members or caregivers should be solicited to assist in medication administration, taught how to administer the medications, and instructed on methods to evaluate effectiveness. These significant persons in the child’s life, individuals who know the child on a day-to-day basis, are usually in the best position to evaluate the effectiveness of a medication and observe for adverse reactions. Some adverse reactions of medication in a child (e.g., ringing in ears, nausea) may be difficult to evaluate; those closest to the child may be in the best position to assess for these responses. However, parents or other family members may request not to participate in invasive procedures. This request should be respected, and parents or guardians should be encouraged to provide comfort to the child after medication is administered. Caregivers should always be supported in their caring function so that the child feels safe and secure.

Cognitive issues must be addressed such as the ability to understand (1) the reason for the medication, (2) the need for the medication despite unpleasant taste or method of administration, and (3) the need to complete all doses and courses of medication. When the family is taught about pediatric drug administration, education for the child—at a developmentally appropriate level—must also be included. Communication with the child and family must always consider level of knowledge, developmental age, cultural factors, and levels of anxiety. The nurse should use optimal interpersonal skills to ensure the best outcome in the administration of medications to pediatric patients.

The primary concerns in administering medications to infants are maintaining safety with the minimum restraint necessary, administering the correct dosage, and providing care with as much comforting as possible. Toddlers may react violently and negatively to medication administration. Simple explanations, a firm approach, and enlisting the imagination of a toddler through play may enhance success with medication administration. Preschoolers are fairly cooperative and respond well to age-appropriate explanations. Allowing some level of choice and control may facilitate success with preschool children. School-age children, although often cooperative, may fear bodily injury and should be permitted even more control, involvement in the process, and information. Age-appropriate fears related to pain, changes in body image, and injury are prevalent among older school-age and adolescent patients. The nurse should establish a positive rapport with the patient, contract with the adolescent related to the plan of care, and ensure privacy in all aspects of medication administration. Parents or guardians must be able to practice and repeat the psychomotor skills associated with medication administration.

Most pediatric medications are administered via the oral route. This route is the least invasive and easiest to use and can be used by family and home caregivers. Topical, rectal, and parenteral routes (i.e., subQ, IM, IV) are also used to deliver medications to pediatric patients for whom the oral route is contraindicated. Because of tissue differences among children, the IV route is more predictable than other routes.

Most oral medications are administered to children using an oral syringe. Oral syringes ensure more exact dosing and are relatively easy to use. Syringes may be marked to ensure correct dosages. The syringe is inserted into either side of the mouth and pointed toward the buccal mucosa. Depositing the medication too close to the front of the mouth increases the likelihood that the medication will be spit out. Pointing the syringe directly toward the back of the mouth may increase the risk for gagging or choking. Infants may suck medication from a bottle nipple into which the measured medication has been squirted from the oral syringe. Preschool and school-age children are usually able to inject oral medication into their own mouths, enhancing their sense of control over what can be an anxiety-provoking situation.

Nurses may need to crush pills or dissolve capsules in fluid for administration to pediatric patients. It is the nurse’s responsibility to access information on the advisability of crushing or dissolving a medication before administration; some medications, such as time-released or enteric-coated medications, should not be crushed or dissolved. Some medications may be made more palatable by adding jelly, syrup, or honey (infants younger than 1 year should not be given honey because of the risk of botulism). Small volumes should be used to dilute medications so the patient is ensured the full dose. As pediatric medication research increases, more medications will be available in stable liquid pediatric forms. Until then, the nurse should work closely with pharmacy and hospital policies to ensure safe administration of oral medications to children. For children who refuse to take medication by mouth or children who require tube feeding, oral medications can be administered via nasogastric, orogastric, or gastrostomy tubes. Precautions required when giving medications via this route are similar to those implemented when administering feedings.

The administration of subQ, IM, and IV medications to children includes many of the same principles as adults, with additional considerations. Safe restraint and atraumatic care principles should be used when possible. Hockenberry defines atraumatic care as the delivery of therapeutic care through the implementation of interventions that “eliminate or minimize the psychological and physical distress experienced by children and their families in the health care system.” Depending on developmental age, the child may have incorrect interpretations about the need for medication, believing that the medication is a punishment or a result of wrongdoing. The nurse should provide preparation for the procedure at the appropriate level for the child and involve caregivers in all aspects of care. One method to ensure atraumatic care is through the use of topical analgesics on the site before IM, subQ, or IV injections. Eutectic mixture of local anesthetics (EMLA), a topical cream, anesthetizes the site of injection if applied 1 to 2.5 hours before injection. After EMLA is applied to the injection site, the site is covered with a transparent dressing for containment. Also available are iontophoresis (Numby Stuff), a vasocoolant spray, and buffered lidocaine injections. Powdered lidocaine preparations are effective in reducing the pain and fear associated with invasive procedures in children, such as venipuncture. LET (lidocaine, epinephrine, and tetracaine) is another topical anesthetic agent used for children undergoing invasive procedures.

Based on the cognitive level of the child, distraction and other nonpharmacologic methods of pain and anxiety control can also be used to decrease the perception of pain. The use of creative imagery and hypnosis with toddlers and preschool children has been explored as a pain-management strategy. Wallace and colleagues describe the “cough trick,” in which children are taught to initiate a cough during injections. This method is effective in reducing perceptions of pain in children during immunizations. Injections should never be given to a sleeping child with the intent to surprise the child with a quick procedure. The child may subsequently experience a lack of trust and be reluctant to sleep in the future.

IV infusion sites must be protected, especially in infants and toddlers, who do not understand the rationale or importance of maintaining the IV site. Commercial products are available to protect the IV site and maintain an intact IV infusion set. Stocking-like covers may hide the IV site from infants before they master the concept of object permanence. The patency of an IV site should be checked before each medication administration to avoid infiltration and extravasation. Any injection site on a preschooler should be covered with a bandage, preferably a decorated one, so that the child does not fear “leakage” from the area. Selection of injection and IV sites is made based on developmental variables, site of preference, and access to administration sites. The dorsogluteal site is no longer recommended for pediatric patients because of lack of development of the muscle and potential for sciatic nerve damage. The ventrogluteal or the vastus lateralis are preferred sites for pediatric IM injections. The length of the needle depends on the child’s muscle mass and subQ tissue and the site of injection. The child may prefer subQ injections in the leg or upper arm rather than in the abdomen. IV sites may be difficult to find in children. Amount of fat tissue, hydration status of the child, and ability to isolate and immobilize veins are all mitigating factors.

When administering medications to children, follow these basic principles: honesty, respect, age-appropriate teaching and explanations, attention to safety, atraumatic care, using the least amount of restraint necessary, providing positive reinforcement for age-appropriate cooperation, refraining from use of negative messages or behaviors, and upholding family-centered principles. These standards may be used throughout the pediatric life span and highlight the need for nursing intervention that is sensitive, individualized, and caring.