BUPROPION HYDROCHLORIDE

BUPROPION HYDROCHLORIDE
(byoo-pro'pi-on)
Wellbutrin, Wellbutrin SR, Wellbutrin XL, Zyban
Classifications: psychotherapeutic; antidepressant;
Therapeutic:antidepressant
Pregnancy Category: B

Availability

75 mg, 100 mg tablets; 100 mg, 150 mg, 200 mg sustained-release tablets; 150 mg, 300 mg extended-release tablets

Action

The neurochemical mechanism of bupropion is not fully understood. It selectively inhibits the neuronal reuptake of dopamine.

Therapeutic Effect

Its antidepressive effect is related to CNS stimulant effects.

Uses

Indicated for mental depression; since it has been associated with increased risk of seizures, it is not the agent of first choice; adjunct for smoking cessation; seasonal affective disorder.

Unlabeled Uses

Schizoaffective disorders.

Contraindications

Hypersensitivity to bupropion; history of seizure disorder; current or prior diagnosis of bulimia or anorexia nervosa; suicidal ideation; concurrent administration of an MAO inhibitor; head trauma; seizure disorder; CNS tumor; recent MI; abrupt discontinuation, anorexia nervosa, bulimia nervosa, children <18 y; lactation.

Cautious Use

Renal or hepatic function impairment; drug abuse or dependence; pregnancy (category B); cardiac disease, MI, hepatic disease, biliary cirrhosis; hypertension, bipolar disorder, mania, psychosis, diabetes mellitus, older adults, ethanol intoxication, tics, Tourette's syndrome.

Route & Dosage

Depression/Seasonal Affective Disorder
Adult: PO 75–100 mg t.i.d., start with 75 mg t.i.d., or 100 mg SR b.i.d., or 150 mg XL q.d., and increase dose q3d to 300 mg/d; doses >450 mg/d are associated with an increased risk of adverse reactions including seizures
Geriatric: PO 50–100 mg/d, may increase by 50–100 mg q3–4d (max: 150 mg/dose)

Smoking Cessation
Adult: PO Start with 150 mg once daily x 3 d, then increase to 150 mg b.i.d. (max: 300 mg/d) for 7–12 wk

Administration

Oral

Give with meals to decrease incidence of nausea and vomiting.
Ensure that sustained-release tablets are not chewed or crushed. They must be swallowed whole.
Note: Increases in dosage should not exceed 100 mg/d over a 3-d period. Greater increments increase the seizure potential.
Store away from heat, direct light, and moisture.

Adverse Effects (≥1%)

Body as a Whole: Weight loss, weight gain. CNS: Seizures. The risk of seizure appears to be strongly associated with dose (especially >450 mg/d) and may be increased by predisposing factors (e.g., head trauma, CNS tumor) or a history of prior seizure; agitation, insomnia, dry mouth, blurred vision, headache, dizziness, tremor. GI: Nausea, vomiting, constipation. CV: Tachycardia. Skin: Rash.

Interactions

Drug: May increase metabolism of carbamazepine, cimetidine, phenytoin, phenobarbital, decreasing their effect; may increase incidence of adverse effects of levodopa, mao inhibitors.

Pharmacokinetics

Absorption: Readily from GI tract. Onset: 3–4 wk. Peak: 1–3 h. Metabolism: In liver (including first pass metabolism) to active metabolites by CYP2B6. Elimination: 80% in urine as inactive metabolites Half-Life: 8–24 h.

Nursing Implications

Assessment & Drug Effects

Monitor for therapeutic effectiveness. The full antidepressant effect of drug may not be realized for 4 or more weeks.
Close observation for worsening of depression or suicidal tendencies.
Use extreme caution when administering drug to patient with history of seizures, cranial trauma, or other factors predisposing to seizures; during sudden and large increments in dose, seizure potential is increased.
Report significant restlessness, agitation, anxiety, and insomnia. Symptoms may require treatment or discontinuation of drug.
Monitor for and report delusions, hallucinations, psychotic episodes, confusion, and paranoia.
Lab tests: Monitor hepatic and renal function tests while patient is taking this drug.

Patient & Family Education

Take drug at the same times each day.
Monitor your weight at least weekly. Report significant changes in weight (±5 lb) to physician.
Minimize or avoid alcohol because it increases the risk of seizures.
Do not drive or engage in potentially hazardous activities until response to drug is known because judgment or motor and cognitive skills may be impaired.
Do not abruptly discontinue drug. Gradual dosage reduction may be necessary to prevent adverse effects.
Do not take any OTC drugs without consulting physician.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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