L

L

labetalol

la-bay-ta-lol

(Apo-Labetalol , Normodyne , Trandate)

Do not confuse labetalol with betaxolol, metoprolol or propranolol, or Trandate with tramadol or Trental.

Fixed-combination(s)

Normozide: labetalol/hydrochlorothiazide (a diuretic): 100 mg/25 mg, 200 mg/25 mg, 300 mg/25 mg.

classification

PHARMACOTHERAPEUTIC: Alpha-, beta-adrenergic blocker. CLINICAL: Antihypertensive (see p. 73C).

Action

Blocks alpha₁-, beta₁-, beta₂– (large doses) adrenergic receptor sites. Large doses increase airway resistance. Therapeutic Effect: Slows sinus heart rate; decreases peripheral vascular resistance, cardiac output, B/P.

Pharmacokinetics

Route	Onset	Peak	Duration
PO	0.5–2 hrs	2–4 hrs	8–12 hrs
IV	2–5 min	5–15 min	2–4 hrs

Completely absorbed from GI tract. Protein binding: 50%. Metabolized in liver. Primarily excreted in urine. Not removed by hemodialysis. Half-life: 2.5–8 hrs.

Uses

Management of mild to severe hypertension. May be used alone or in combination with other antihypertensives. OFF-LABEL: Management of preeclampsia, severe hypertension in pregnancy, hypertension during acute ischemic stroke, pediatric hypertension.

Precautions

Contraindications: Bronchial asthma, cardiogenic shock, uncompensated HF, second- or third-degree heart block (except in pts with functioning pacemaker), severe bradycardia, conditions associated with severe, prolonged hypotension. Cautions: Compensated HF, severe anaphylaxis to allergens, myasthenia gravis, psychiatric disease, hepatic impairment, pheochromocytoma, diabetes mellitus; concurrent use with digoxin, verapamil, or diltiazem; arterial obstruction.

Lifespan considerations

Pregnancy/Lactation: Drug crosses placenta. Small amount distributed in breast milk. Pregnancy Category C (D if used in second or third trimester). Children: Safety and efficacy not established. Elderly: Age-related peripheral vascular disease may increase susceptibility to decreased peripheral circulation.

Interactions

DRUG: May decrease effects of beta₂ agonists, theophylline. Beta blockers, digoxin may increase risk of bradycardia. HERBAL: Ephedra, ginseng, yohimbe may worsen hypertension. Garlic may increase antihypertensive effect. Licorice may cause water retention, increased serum sodium, decreased serum potassium. FOOD: None known. LAB VALUES: May increase serum antinuclear antibody titer (ANA), BUN, LDH, alkaline phosphatase, bilirubin, creatinine, potassium, triglycerides, lipoprotein, uric acid, AST, ALT.

Availability (Rx)

Injection Solution (Trandate): 5 mg/ml. Tablets (Trandate): 100 mg, 200 mg, 300 mg.

Administration/handling

IV

◀ ALERT ▶ Pt must be in supine position for IV administration and for 3 hrs after initially receiving medication (substantial drop in B/P upon standing should be expected).

Reconstitution • For IV infusion, dilute in D₅W to provide concentration of 1–2 mg/ml.

Rate of Administration • For IV push, give over 2–3 min at 10-min intervals. • Do not administer faster than 2 mg/min. • For IV infusion, administer at rate of 2 mg/min initially. Rate is adjusted according to B/P. • Monitor B/P immediately before and q5–10min during IV administration (maximum effect occurs within 5 min).

Storage • Store at room temperature. • After dilution, IV solution is stable for 24 hrs. • Solution appears clear, colorless to light yellow. • Discard if discolored or precipitate forms.

PO

• Give without regard to food. • Tablets may be crushed.

IV incompatibilities

Amphotericin B complex (Abelcet, AmBisome, Amphotec), ceftaroline (Teflaro), ceftriaxone (Rocephin), furosemide (Lasix), heparin, nafcillin (Nafcil).

IV compatibilities

Amiodarone (Cordarone), calcium gluconate, dexmedetomidine (Precedex), diltiazem (Cardizem), dobutamine (Dobutrex), dopamine (Intropin), enalapril (Vasotec), fentanyl (Sublimaze), hydromorphone (Dilaudid), lidocaine, lorazepam (Ativan), magnesium sulfate, midazolam (Versed), milrinone (Primacor), morphine, nitroglycerin, norepinephrine (Levophed), potassium chloride, potassium phosphate, propofol (Diprivan).

Indications/routes/dosage

Hypertension

PO: ADULTS: Initially, 100 mg twice a day. Adjust in increments of 100 mg twice a day q2–3days. Maintenance: 100–400 mg twice a day. Maximum: 2.4 g/day. ELDERLY: Initially, 100 mg 1–2 times a day. May increase as needed. Maintenance: 100–200 mg twice daily. CHILDREN: 1–3 mg/kg/day in 2 divided doses. Maximum: 10–12 mg/kg/day up to 1,200 mg/day.

Severe hypertension, hypertensive crisis

IV: ADULTS: Initially, 20 mg. Additional doses of 40–80 mg may be given at 10-min intervals, up to total dose of 300 mg.

IV Infusion: ADULTS: Initially, 2 mg/min up to total dose of 300 mg. CHILDREN: 0.4–1 mg/kg/hr. Maximum: 3 mg/kg/hr.

Side effects

Frequent (20%–11%): Drowsiness, dizziness, excessive fatigue. Occasional (10% or less): Dyspnea, peripheral edema, depression, anxiety, constipation, diarrhea, nasal congestion, weakness, diminished sexual function, transient scalp tingling, insomnia, nausea, vomiting, abdominal discomfort. Rare: Altered taste, dry eyes, increased urination, paresthesia.

Adverse effects/toxic reactions

May precipitate, aggravate HF due to decreased myocardial stimulation. Abrupt withdrawal may precipitate myocardial ischemia, producing chest pain, diaphoresis, palpitations, headache, tremor. May mask signs, symptoms of acute hypoglycemia (tachycardia, B/P changes) in diabetic pts.

Nursing considerations

Baseline assessment

Assess baseline renal/hepatic function tests. Assess B/P, apical pulse immediately before drug administration (if pulse is 60/min or less or systolic B/P is lower than 90 mm Hg, withhold medication, contact physician).

Intervention/evaluation

Monitor B/P for hypotension. Assess pulse for quality, irregular rate, bradycardia. Monitor EKG for cardiac arrhythmias. Monitor daily pattern of bowel activity, stool consistency. Assist with ambulation if dizziness occurs. Assess for evidence of HF: dyspnea (particularly on exertion or lying down), night cough, peripheral edema, distended neck veins. Monitor I&O (increase in weight, decrease in urine output may indicate HF).

Patient/family teaching

• Do not discontinue drug except upon advice of physician (abrupt discontinuation may precipitate heart failure). • Rise slowly from sitting position. • Compliance with therapy regimen is essential to control hypertension, arrhythmias. • Avoid tasks that require alertness, motor skills until response to drug is established. • Report shortness of breath, excessive fatigue, weight gain, prolonged dizziness, headache. • Do not use nasal decongestants, OTC cold preparations (stimulants) without physician approval. • Limit alcohol.

lacosamide

la-koe-sa-myde

Do not confuse lacosamide with zonisamide.

classification

PHARMACOTHERAPEUTIC: Succinimide (Schedule V). CLINICAL: Anticonvulsant (see p. 36C).

Action

Selectively enhances slow inactivation of sodium channels, stabilizing hyperexcitable neuronal membranes and inhibits neuronal firing. Therapeutic Effect: Produces anticonvulsant effect.

Pharmacokinetics

Completely absorbed following PO administration. Protein binding: 15%. Peak plasma concentration: 1–4 hrs after oral dosing and is reached at the end of IV infusion. Primarily excreted in urine. Steady-state levels achieved in 3 days. Removed by hemodialysis. Half-life: 13 hrs.

Uses

Tablets used as adjunctive therapy for treatment of partial-onset seizures in pts 17 yrs and older with epilepsy. Injection form indicated as adjunctive therapy for treatment of partial-onset seizures in pts 17 years and older with epilepsy when oral administration is temporarily not feasible.

Precautions

Contraindications: None known. Cautions: Renal/hepatic impairment, cardiac conduction problems (e.g., marked first-degree AV block, second-degree or higher AV block, sick sinus syndrome without pacemaker), myocardial ischemia, HF, high risk of suicide.

Lifespan considerations

Pregnancy/Lactation: Unknown if distributed in breast milk. Pregnancy Category C. Children: Safety and efficacy not established in pts younger than 17 yrs. Elderly: No age-related precautions noted.

Interactions

DRUG: None significant. HERBAL: None significant. FOOD: None known. LAB VALUES: May increase serum ALT, proteinuria.

Availability (Rx)

Injection Solution: 10 mg/ml (20 ml). Oral Solution: 10 mg/ml.

Tablets: 50 mg, 100 mg, 150 mg, 200 mg.

Administration/handling

PO

• Give without regard to meals. • Do not crush or break film-coated tablets. • Oral solution should be administered with a calibrated measuring device. • Discard any unused portion after 7 wks.

IV

• Appears as a clear, colorless solution. • Discard unused portion or if precipitate or discoloration is present. • If mixing with diluent, may be stored for 24 hrs at room temperature. Infuse over 30–60 min.

IV compatibilities

0.9% NaCl, D₅W, lactated Ringer’s.

Indications/routes/dosage

Note: IV dose is same as oral dose.

Partial-onset seizures

PO: ADULTS, CHILDREN 17 YRS AND OLDER: Initially, 50 mg twice daily (100 mg/day). May increase by 100 mg/day at weekly intervals, given as 2 daily divided doses up to maintenance dose of 200–400 mg/day, based on pt response, tolerability.

IV: ADULTS, CHILDREN 17 YRS AND OLDER: May be given undiluted or mixed in compatible diluent and given as 30- to 60-min infusion.

Switch from IV to PO

When switching from IV to PO form, use same equivalent daily dosage and frequency as IV administration.

Switch from PO to IV

When switching from PO to IV form, initial total daily IV dosage should be equivalent to total daily dosage and frequency of PO form and should be infused IV over 30–60 min.

Severe renal impairment (creatinine clearance 30 ml/min or less, pts with end-stage renal disease)

PO/IV: ADULTS, ELDERLY, CHILDREN 17 YRS AND OLDER: Maximum: 300 mg/day.

Hemodialysis: Supplement dose of up to 50% may be given after 4-hr HD treatment.

Mild to moderate hepatic impairment

PO/IV: ADULTS, ELDERLY, CHILDREN 17 YRS AND OLDER: Maximum: 300 mg/day.

Side effects

Frequent (31%–13%): Dizziness, headache. Occasional (11%–5%): Nausea, double vision, vomiting, fatigue, blurred vision, ataxia (difficulty with balance, coordination, slurred speech), tremor, nystagmus (involuntary horizontal movement of eyeball). Rare (4%–2%): Vertigo, diarrhea, gait disturbances, memory impairment, depression, pruritus, injection site discomfort.

Adverse effects/toxic reactions

Increased risk of suicidal ideation, behavior. Dose-dependent prolongations in PR interval noted. Leukopenia, anemia, thrombocytopenia occur rarely.

Nursing considerations

Baseline assessment

Review history of seizure disorder (intensity, frequency, duration, level of consciousness). Initiate seizure precautions. Hepatic/renal function tests, CBC should be performed before therapy begins and periodically during therapy.

Intervention/evaluation

Observe for recurrence of seizure activity. Assess for clinical improvement (decrease in intensity/frequency of seizures). Assist with ambulation if dizziness occurs. Assess for suicidal ideation, depression, behavioral changes. Drug should be withdrawn gradually (over a minimum of 1 wk) to minimize potential for increased seizure frequency.

Patient/family teaching

• Strict maintenance of drug therapy is essential for seizure control. • Avoid tasks that require alertness, motor skills until response to drug is established. • Avoid alcohol. • Report depression, suicidal ideation, unusual behavioral changes.

lactulose

lak-too-lohs

(Acilac , Apo-Lactulose , Constulose, Enulose, Generlac, Kristalose, Laxilose )

Do not confuse lactulose with lactose.

classification

PHARMACOTHERAPEUTIC: Lactose derivative. CLINICAL: Hyperosmotic laxative, ammonia detoxicant (see p. 126C).

Action

Prevents reabsorption of ammonia, producing osmotic effect. Therapeutic Effect: Promotes increased peristalsis, bowel evacuation; decreases serum ammonia concentration.

Pharmacokinetics

Poorly absorbed from GI tract. Extensively metabolized in colon. Primarily excreted in feces.

Uses

Prevention, treatment of portal-systemic encephalopathy (including hepatic precoma, coma); treatment of chronic constipation.

Precautions

Contraindications: Pts requiring a low-galactose diet. Cautions: Diabetes mellitus, hepatic impairment, dehydration.

Lifespan considerations

Pregnancy/Lactation: Unknown if drug crosses placenta or is distributed in breast milk. Pregnancy Category B. Children: Avoid use in those younger than 6 yrs (usually unable to describe symptoms). Elderly: No age-related precautions noted.

Interactions

DRUG: None significant. HERBAL: None significant. FOOD: None known. LAB VALUES: May decrease serum potassium (GI loss).

Availability (Rx)

Packets (Kristalose): 10 g, 20 g. Solution, Oral (Constulose, Enulose, Generlac): 10 g/15 ml.

Administration/handling

PO

• Store solution at room temperature. • Solution appears pale yellow to yellow, viscous liquid. Cloudiness, darkened solution does not indicate potency loss. • Drink water, juice, milk with each dose (aids stool softening, increases palatability). • Mix packets with 4 oz water.

Rectal

• Lubricate anus with petroleum jelly before enema insertion. • Insert carefully (prevents damage to rectal wall) with nozzle toward navel. • Squeeze container until entire dose expelled. • Instruct pt to retain 30–60 min in divided doses. Maximum: 60 ml/day (40 g/day).

Indications/routes/dosage

Constipation

PO: ADULTS, ELDERLY: 15–30 ml (10–20 g)/day, up to 60 ml (40 g)/day. CHILDREN: 1–3 ml/kg/day (0.7–2 g/kg/day).

Prevention of portal-systemic encephalopathy

ADULTS, ELDERLY: 30–45 ml 3–4 times/day. CHILDREN: 40–90 ml/day in divided doses 3–4 times a day. INFANTS: 2.5–10 ml/day in 3–4 divided doses. Adjust dose q1–2 days to produce 2–3 soft stools/day.

Treatment of portal-systemic encephalopathy

PO: ADULTS, ELDERLY: Initially, 30–45 ml (20–30 g) every hr to induce rapid laxation. Then, 30–45 ml 3–4 times a day. Adjust dose q1–2days to produce 2–3 soft stools a day.

Rectal administration (as retention enema)

200 g (300 ml) diluted with 700 ml water or NaCl via rectal balloon catheter. Retain 30–60 min q4–6h. (Transition to oral prior to stopping rectal administration.)

Side effects

Occasional: Abdominal cramping, flatulence, increased thirst, abdominal discomfort. Rare: Nausea, vomiting.

Adverse effects/toxic reactions

Severe diarrhea indicates overdose. Long-term use may result in laxative dependence, chronic constipation, loss of normal bowel function.

Nursing considerations

Intervention/evaluation

Encourage adequate fluid intake. Assess bowel sounds for peristalsis. Monitor daily pattern of bowel activity, stool consistency; record time of evacuation. Assess for abdominal disturbances. Monitor serum electrolytes in pts with prolonged, frequent, excessive use of medication.

Patient/family teaching

• Evacuation occurs in 24–48 hrs of initial dose. • Institute measures to promote defecation: increase fluid intake, exercise, high-fiber diet.

lamivudine

la-miv-yoo-deen

(Epivir, Epivir-HBV, Heptovir )

BLACK BOX ALERT Serious, sometimes fatal lactic acidosis, severe hepatomegaly with steatosis (fatty liver) have occurred. Pts must be monitored for chronic hepatitis B for several months following therapy.

Do not confuse Epivir with Combivir, or lamivudine with lamotrigine.

Fixed-combination(s)

Combivir: lamivudine/zidovudine (an antiviral): 150 mg/300 mg. Epzicom: lamivudine/abacavir (an antiviral): 300 mg/600 mg. Trizivir: lamivudine/zidovudine/abacavir (an antiviral): 150 mg/300 mg/300 mg.

classification

PHARMACOTHERAPEUTIC: Nucleoside reverse transcriptase inhibitor. CLINICAL: Antiviral (see pp. 70C, 118C).

Action

Inhibits HIV reverse transcriptase by viral DNA chain termination. Inhibits RNA-, DNA-dependent DNA polymerase, an enzyme necessary for HIV replication. Therapeutic Effect: Slows HIV replication, reduces progression of HIV infection.

Pharmacokinetics

Rapidly, completely absorbed from GI tract. Protein binding: less than 36%. Widely distributed (crosses blood-brain barrier). Primarily excreted unchanged in urine. Not removed by hemodialysis or peritoneal dialysis. Half-life: Children: 2 hrs. Adults: 5–7 hrs.

Uses

Epivir: Treatment of HIV infection in combination with at least two other antiretroviral agents. Epivir-HBV: Treatment of chronic hepatitis B associated with evidence of hepatitis B viral replication and active liver inflammation. OFF-LABEL: Prophylaxis in health care workers at risk of acquiring HIV after occupational exposure to virus. Use as part of multidrug regimen.

Precautions

Contraindications: None known. Cautions: Use in children with history of pancreatitis or risk factors for developing pancreatitis. Use in combination with interferon alfa with or without ribavirin in HIV/HBV coinfected pts, renal/hepatic impairment.

Lifespan considerations

Pregnancy/Lactation: Drug crosses placenta. Unknown if distributed in breast milk. Breastfeeding not recommended (possibility of HIV transmission). Pregnancy Category C. Children: Safety and efficacy not established in those younger than 3 mos. Elderly: Age-related renal impairment may require dosage adjustment.

Interactions

DRUG: Zalcitabine may inhibit absorption of both drugs; avoid concurrent administration. HERBAL: None significant. FOOD: None known. LAB VALUES: May increase Hgb, neutrophil count, serum amylase, AST, ALT, bilirubin.

Availability (Rx)

Oral Solution: 5 mg/ml (Epivir-HBV), 10 mg/ml (Epivir). Tablets: 100 mg (Epivir-HBV), 150 mg (Epivir), 300 mg (Epivir).

Administration/handling

PO

• Give without regard to meals.

Indications/routes/dosage

HIV infection

PO: ADULTS WEIGHING 50 KG OR MORE: 150 mg twice a day or 300 mg once a day. ADULTS WEIGHING LESS THAN 50 KG: 4 mg/kg twice a day (up to 150 mg/dose). CHILDREN 4 MOS–16 YRS: 4 mg/kg twice a day (up to 150 mg/dose). INFANTS 1–3 MOS: 4 mg/kg twice/day. NEONATES YOUNGER THAN 30 DAYS: 2 mg/kg twice/day.

Chronic hepatitis B

PO: ADULTS: 100 mg/day. CHILDREN 2–17 YRS: 3 mg/kg/day. Maximum: 100 mg/day.

Dosage in renal impairment

Dosage and frequency are modified based on creatinine clearance.

Creatinine Clearance	Dosage HIV	Dosage Hepatitis B
30–49 ml/min	150 mg once a day	100 mg first dose, then 50 mg once a day
15–29 ml/min	150 mg first dose, then 100 mg once a day	100 mg first dose, then 25 mg once a day
5–14 ml/min	150 mg first dose, then 50 mg once a day	35 mg first dose, then 15 mg once a day
Less than 5 ml/min	50 mg first dose, then 25 mg once a day	35 mg first dose, then 10 mg once a day

Hemodialysis: Dosing post-HD recommended.

Side effects

Frequent (35%–10%): Headache, nausea, malaise, fatigue, nasal disturbances, diarrhea, cough, musculoskeletal pain, neuropathy, insomnia, anorexia, dizziness, fever, chills. Occasional (9%–5%): Depression, myalgia, abdominal cramps, dyspepsia, arthralgia.

Adverse effects/toxic reactions

Pancreatitis occurs in 13% of pediatric pts. Anemia, neutropenia, thrombocytopenia occur rarely. Lactic acidosis, severe hepatomegaly with steatosis have been reported.

Nursing considerations

Baseline assessment

Establish baseline lab values, esp. renal function. Screen HIV pt for hepatitis B infection before initiating therapy.

Intervention/evaluation

Monitor BUN, serum creatinine, amylase, lipase, ALT, AST, bilirubin. Assess for headache, nausea, cough. Monitor daily pattern of bowel activity, stool consistency. Modify diet or administer laxative as needed. Assess for dizziness, sleep pattern. If pancreatitis in children occurs, movement aggravates abdominal pain; sitting up, flexing at the waist relieves the pain.

Patient/family teaching

• Continue therapy for full length of treatment. • Doses should be evenly spaced. • Lamivudine is not a cure for HIV infection, nor does it reduce risk of transmission to others. • Avoid tasks requiring alertness, motor skills until response to drug is established. • Avoid alcohol. • Closely monitor for symptoms of pancreatitis (severe, steady abdominal pain often radiating to the back, clammy skin, hypotension; nausea/vomiting may accompany abdominal pain).

lamotrigine

la-moe-tri-jeen

(Apo-Lamotrigine , Lamictal, Lamictal ODT, Lamictal XR, Novo-Lamotrigine )

BLACK BOX ALERT Severe, potentially life-threatening skin rashes have been reported, including Stevens-Johnson syndrome. Risk increased with coadministration with valproic acid and rapid-dose titration.

Do not confuse Lamictal with Lamisil or Lomotil, or lamotrigine with labetalol or lamivudine.

classification

PHARMACOTHERAPEUTIC: Phenyltriazine. CLINICAL: Anticonvulsant (see p. 36C).

Action

May block voltage-sensitive sodium channels, stabilizing neuronal membranes, regulating presynaptic transmitter release of excitatory amino acids. Therapeutic Effect: Produces anticonvulsant activity. Delays time to occurrence of acute mood episodes (mania, depression, hypomania).

Uses

Adjunctive therapy in adults and children with generalized tonic-clonic seizures and partial seizures, treatment of adults and children with generalized seizures of Lennox-Gastaut syndrome. Conversion to monotherapy in adults treated with another enzyme-inducing antiepileptic drug (EIAED) (e.g., valproic acid, carbamazepine, phenytoin, phenobarbital, primidone). Long-term maintenance treatment of bipolar disorder. Treatment of pts 2 yrs and older with primary generalized tonic-clonic seizures. Extended-release: Adjunctive therapy for primary generalized tonic-clonic and partial-onset seizures in pts 13 yrs and older. Conversion to monotherapy in pt 13 yrs and older with partial seizures receiving treatment with a single antiepileptic drug (AED).

Precautions

Contraindications: None known. Cautions: Renal, hepatic, cardiac impairment, pts at high risk of suicide, pts taking estrogen-containing oral contraceptives.

Lifespan considerations

Pregnancy/Lactation: Distributed in breast milk. Breastfeeding not recommended. Increased fetal risk of oral cleft formation has been noted with use during pregnancy. Pregnancy Category C. Children: Safety and efficacy in those 18 yrs and younger with bipolar disorder, younger than 13 yrs with epilepsy not established. Elderly: Age-related renal impairment may require dosage adjustment.

Interactions

DRUG: Carbamazepine, phenobarbital, primidone, phenytoin, rifampin may decrease concentration. Valproic acid may increase concentration/effects. Oral contraceptives may decrease concentration. HERBAL: Evening primrose may decrease seizure threshold. FOOD: None known. LAB VALUES: None significant.

Availability (Rx)

Tablets: 25 mg, 100 mg, 150 mg, 200 mg. Tablets (Chewable): 2 mg, 5 mg, 25 mg. Tablets (Orally Disintegrating): 25 mg, 50 mg, 100 mg, 200 mg.

Tablets (Extended-Release): 25 mg, 50 mg, 100 mg, 200 mg, 250 mg, 300 mg.

Administration/handling

PO

• Give without regard to food. • Chewable tablets may be dispensed in water or diluted fruit juice, or swallowed whole. • Extended-release tablets must be swallowed whole; do not break, cut, crush, or divide. • Place orally disintegrating tablet on tongue, allow to dissolve. Pt must not break, cut, or chew. Can be swallowed without regard to food or water.

Indications/routes/dosage

Lennox-Gastaut, primary generalized tonic-clonic seizures, partial seizures

PO: ADULTS, ELDERLY, CHILDREN OLDER THAN 12 YRS: Initially, 25 mg/day for 2 wks, then increase to 50 mg/day for 2 wks. After 4 wks, may increase by 50 mg/day at 1- to 2-wk intervals. Maintenance: 225–375 mg/day in 2 divided doses. CHILDREN 2–12 YRS: Initially, 0.3 mg/kg/day in 1–2 divided doses for 2 wks, then increase to 0.6 mg/kg/day in 1–2 divided doses for 2 wks. After 4 wks, may increase by 0.6 mg/kg/day at 1- to 2-wk intervals. Maintenance: 4.5–7.5 mg/kg/day in 2 divided doses. Maximum: 300 mg/day in 2 divided doses.

Adjusted dosage with antiepileptic drugs containing valproic acid

PO: ADULTS, ELDERLY, CHILDREN OLDER THAN 12 YRS: Initially, 25 mg every other day for 2 wks, then increase to 25 mg/day for 2 wks. After 4 wks, may increase by 25–50 mg/day at 1- to 2-wk intervals. Maintenance: 100–400 mg/day in 2 divided doses (100–200 mg/day when taking lamotrigine with valproic acid alone). CHILDREN 2–12 YRS: Initially, 0.15 mg/kg/day in 1–2 divided doses for 2 wks, then increase to 0.3 mg/kg/day in 1–2 divided doses for 2 wks. After 4 wks, may increase by 0.3 mg/kg/day at 1- to 2-wk intervals. Maintenance: 1–5 mg/kg/day in 2 divided doses. Maximum: 200 mg/day in 2 divided doses.

Adjusted dosage with EIAED without valproic acid

PO: ADULTS, ELDERLY, CHILDREN OLDER THAN 12 YRS: Initially, 50 mg/day for 2 wks, then increase to 100 mg/day in 2 divided doses for 2 wks. After 4 wks, may increase by 100 mg/day at 1- to 2-wk intervals. Maintenance: 300–500 mg/day in 2 divided doses. CHILDREN 2–12 YRS: Initially, 0.6 mg/kg/day in 1–2 divided doses for 2 wks, then increase to 1.2 mg/kg/day in 1–2 divided doses for 2 wks. After 4 wks, may increase by 1.2 mg/kg/day at 1- to 2-wk intervals. Maintenance: 5–15 mg/kg/day in 2 divided doses. Maximum: 400 mg/day in 2 divided doses.

Usual maintenance range for extended-release tablets

PT TAKING VALPROIC ACID: 200–250 mg once daily. PT TAKING EIAED WITHOUT VALPROIC ADIC: 400–600 mg once daily. PT NOT TAKING EIAED: 300–400 mg once daily.

Conversion to monotherapy for pts receiving EIAEDs

PO: ADULTS, ELDERLY, CHILDREN 16 YRS AND OLDER: 500 mg/day in 2 divided doses. Titrate to desired dose while maintaining EIAED at fixed level, then withdraw EIAED by 20% each wk over a 4-wk period.

Conversion to monotherapy for pts receiving valproic acid

PO: ADULTS, ELDERLY, CHILDREN 16 YRS AND OLDER: Titrate lamotrigine to 200 mg/day, maintaining valproic acid dose. Maintain lamotrigine dose and decrease valproic acid to 500 mg/day, no greater than 500 mg/day/wk, then maintain 500 mg/day for 1 wk. Increase lamotrigine to 300 mg/day and decrease valproic acid to 250 mg/day. Maintain for 1 wk, then discontinue valproic acid and increase lamotrigine by 100 mg/day each wk until maintenance dose of 500 mg/day reached.

Bipolar disorder

PO: ADULTS, ELDERLY: Initially, 25 mg/day for 2 wks, then 50 mg/day for 2 wks, then 100 mg/day for 1 wk, then 200 mg/day beginning with wk 6.

Bipolar disorder in pts receiving EIAEDs

PO: ADULTS, ELDERLY: 50 mg/day for 2 wks, then 100 mg/day for 2 wks, then 200 mg/day for 1 wk, then 300 mg/day for 1 wk, then up to usual maintenance dose 400 mg/day in divided doses.

Bipolar disorder in pts receiving valproic acid

PO: ADULTS, ELDERLY: 25 mg/day every other day for 2 wks, then 25 mg/day for 2 wks, then 50 mg/day for 1 wk, then 100 mg/day. Usual maintenance dose with valproic acid: 100 mg/day.

Usual dosage for lamictal XR

Adjunct Therapy: Range: 200–600 mg/day.

Conversion to Monotherapy: Range: 250–500 mg/day.

Discontinuation therapy

◀ ALERT ▶ A dosage reduction of approximately 50% per wk over at least 2 wks is recommended.

Dosage in renal impairment

◀ ALERT ▶ Decreased dosage may be effective in pts with significant renal impairment.

Dosage in hepatic impairment

Moderate to severe without ascites: Reduce dose by 25%. Severe with ascites: Reduce dose by 50%.

Side effects

Frequent (38%–14%): Dizziness, headache, diplopia (double vision), ataxia, nausea, blurred vision, drowsiness, rhinitis. Occasional (10%–5%): Rash, pharyngitis, vomiting, cough, flu-like symptoms, diarrhea, dysmenorrhea, fever, insomnia, dyspepsia. Rare: Constipation, tremor, anxiety, pruritus, vaginitis, hypersensitivity reaction.

Adverse effects/toxic reactions

Abrupt withdrawal may increase seizure frequency. Serious rashes, including Stevens-Johnson syndrome, have been reported.

Nursing considerations

Baseline assessment

Review history of seizure disorder (type, onset, intensity, frequency, duration, LOC), medication history (esp. other anticonvulsants), other medical conditions (e.g., renal impairment). Provide safety precautions; quiet, dark environment. Assess baseline mood, behavior.

Intervention/evaluation

Report occurrence of rash (drug discontinuation may be necessary). Assist with ambulation if dizziness, ataxia occurs. Assess for clinical improvement (decreased intensity/frequency of seizures). Assess for visual abnormalities, headache. Monitor for suicidal ideation, depression, behavioral changes.

Patient/ family teaching

• Take medication only as prescribed; do not abruptly discontinue medication after long-term therapy. • Avoid alcohol. • Avoid tasks that require alertness, motor skills until response to drug is established. • Carry identification card/bracelet to note anticonvulsant therapy. • Strict maintenance of drug therapy is essential for seizure control. • Report any rash, fever, swelling of glands, worsening depression, suicidal ideation, unusual changes in behavior, worsening of seizure control. • May cause photosensitivity reaction; avoid exposure to sunlight, artificial light.

lansoprazole

lan-soe-pra-zol

(Apo-Lansoprazole , First Lansoprazole, Prevacid, Prevacid Solu-Tab, Prevacid 24HR)

Do not confuse lansoprazole with aripiprazole or dexlansoprazole, or Prevacid with Pravachol, Prilosec, or Prinivil.

Fixed-combination(s)

Prevacid NapraPac: lansoprazole/naproxen (an NSAID): 15 mg/375 mg, 15 mg/500 mg. Prevpac: Combination card containing amoxicillin 500 mg (4 capsules), lansoprazole 30 mg (2 capsules), clarithromycin 500 mg (2 tablets).

classification

CLINICAL: Proton pump inhibitor (see p. 147C).

Action

Selectively inhibits gastric parietal cell membrane enzyme system (hydrogen-potassium adenosine triphosphatase, proton pump). Therapeutic Effect: Suppresses gastric acid secretion.

Pharmacokinetics

Rapid, complete absorption (food may decrease absorption) once drug has left stomach. Protein binding: 97%. Distributed primarily to gastric parietal cells. Metabolized in liver. Eliminated in bile and urine. Not removed by hemodialysis. Half-life: 1.5 hrs (increased in hepatic impairment, elderly).

Uses

Short-term treatment (4 wks and less) of healing, symptomatic relief of active duodenal ulcer; short-term treatment (8 wks and less) for healing, symptomatic relief of erosive esophagitis. Long-term treatment of pathologic hypersecretory conditions, including Zollinger-Ellison syndrome. Short-term treatment (8 wks and less) of active benign gastric ulcer, H. pylori–associated duodenal ulcer (part of multidrug regimen), maintenance treatment for healed duodenal ulcer. Treatment of gastroesophageal reflux disease (GERD), NSAID-associated gastric ulcer. OTC: Relief of frequent heartburn (2 or more days/wk). IV: Short-term treatment of erosive esophagitis.

Precautions

Contraindications: None known. Cautions: Hepatic impairment. May increase risk of hip, wrist, spine fractures; GI infections.

Lifespan considerations

Pregnancy/Lactation: Unknown if distributed in breast milk. Pregnancy Category B. Children: Safety and efficacy not established. Elderly: No age-related precautions noted but doses greater than 30 mg not recommended.

Interactions

DRUG: May decrease concentration of atazanavir. May interfere with absorption of ampicillin, digoxin, iron salts, ketoconazole. Sucralfate may delay absorption. May increase effect of warfarin. May decrease effect of clopidogrel. HERBAL: St. John’s wort may decrease concentration/effects. FOOD: Food may decrease absorption. LAB VALUES: May increase LDH, serum alkaline phosphatase, bilirubin, cholesterol, creatinine, AST, ALT, triglycerides, uric acid, Hgb, Hct. May produce abnormal albumin/globulin ratio, electrolyte balance, platelet, RBC, WBC count.

Availability (Rx)

Tablets, Orally Disintegrating (Prevacid Solu-Tab): 15 mg, 30 mg. Powder for Oral Suspension (First Lansoprazole): 3 mg/ml.

Capsules (Delayed-Release): (Prevacid): 15 mg, 30 mg. (Prevacid 24HR): 15 mg.

Administration/handling

PO

• Give while fasting or before meals (food diminishes absorption). • Do not cut/crush delayed-release capsules. • If pt has difficulty swallowing capsules, open capsules, sprinkle granules on 1 tbsp of applesauce, give immediately.

PO (solu-tab)

• Place tablet on tongue; allow to dissolve, then swallow. • May give via oral syringe or nasogastric tube. • May dissolve in 4 ml (15 mg) or 10 ml (30 mg) water.

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Tags: Saunders Nursing Drug Handbook 2015

Mar 8, 2017 | Posted by admin in NURSING | Comments Off

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