Bupropion hydrochloride

bupropion hydrochloride

(byoo proe' pee on)

Wellbutrin, Wellbutrin SR, Wellbutrin XL, Zyban

Pregnancy Category B

Drug classes

Antidepressant

Smoking deterrent

Therapeutic actions

The neurochemical mechanism of the antidepressant effect of bupropion is not understood; it is chemically unrelated to other antidepressant agents; it is a weak blocker of neuronal uptake of serotonin and norepinephrine and inhibits the reuptake of dopamine to some extent.

Indications

·        Treatment of depression

·        Aid to smoking cessation treatment (Zyban)

·        Unlabeled uses: Treatment of neuropathic pain, ADHD

Contraindications and cautions

·        Contraindicated with hypersensitivity to bupropion; history of seizure disorder, bulimia or anorexia, head trauma, CNS tumor (increased risk of seizures); treatment with MAOIs; lactation.

·        Use cautiously with renal or liver disease; heart disease, history of MI, pregnancy.

Available forms

Tablets—75, 100 mg; SR tablets—100, 150, 200 mg; ER tablets—150, 300 mg

Dosages

ADULTS

·        Depression: 300 mg PO given as 100 mg tid; begin treatment with 100 mg PO bid; if clinical response warrants, increase 3 days after beginning treatment. If 4 wk after treatment, no clinical improvement is seen, dose may be increased to 150 mg PO tid (450 mg/day). Do not exceed 150 mg in any one dose. Discontinue drug if no improvement occurs at the 450 mg/day level. Sustained release: 150 mg PO bid; allow at least 8 hr between doses. Extended release: Initially, 150 mg/day PO as a once-a-day dose; range 300–450 mg/day.

·        Smoking cessation: 150 mg (Zyban) PO daily for 3 days, then increase to 300 mg/day in two divided doses at least 8 hr apart. Treat for 7–12 wk.

PEDIATRIC PATIENTS

Safety and efficacy in children < 18 yr not established.

GERIATRIC PATIENTS

Bupropion is excreted through the kidneys; use with caution, and monitor older patients carefully.

Pharmacokinetics

Route	Onset	Peak	Duration
Oral	Varies	2 hr	8–12 hr
SR Oral	Varies	3 hr	16–20 hr
ER Oral	Varies	5 hr	15–25 hr

Metabolism: Hepatic; T_1/2: 14 hr; 21 hr (SR)

Distribution: May cross placenta; may enter breast milk

Excretion: Feces, urine

Adverse effects

·        CNS: Agitation, insomnia, headache, migraine, tremor, ataxia, incoordination, seizures, mania, increased libido, hallucinations, visual disturbances

·        CV: Dizziness, tachycardia, edema, ECG abnormalities, chest pain, shortness of breath

·        Dermatologic: Rash, alopecia, dry skin

·        GI: Dry mouth, constipation, nausea, vomiting, stomatitis

·        GU: Nocturia, vaginal irritation, testicular swelling

·        Other: Weight loss, flulike symptoms

Interactions

Drug-drug

·        Increased risk of adverse effects with levodopa

·        Increased risk of toxicity with MAOIs

·        Increased risk of seizures with drugs that lower seizure threshold, including alcohol

Nursing considerations

Assessment

·        History: Hypersensitivity to bupropion, history of seizure disorder, bulimia or anorexia, head trauma, CNS tumor, treatment with MAOI, renal or liver disease, heart disease, lactation

·        Physical: Skin, weight; orientation, affect, vision, coordination; P, rhythm, auscultation; R, adventitious sounds; bowel sounds, condition of mouth

Interventions

·        Give drug three times a day for depression; do not administer more than 150 mg in any one dose. Administer SR forms twice a day with at least 8 hr between doses.

·        Increase dosage slowly to reduce the risk of seizures.

·        Administer 100-mg tablets four times a day for depression, with at least 4 hr between doses, if patient is receiving > 300 mg/day; use combinations of 75-mg tablets to avoid giving > 150 mg in any single dose.

·        Arrange for patient evaluation after 6 wk.

·        Discontinue MAOI therapy for at least 14 days before beginning bupropion.

·        Monitor LFTs and renal function tests in patients with a history of liver or renal impairment.

·        Have patient quit smoking within first 2 wk of treatment for smoking cessation; may be used with transdermal nicotine.

·        WARNING: Monitor response and behavior; suicide is a risk in depressed patients.

Teaching points

·        Take this drug in equally divided doses three to four times a day as prescribed for depression. Take sustained-release forms twice a day, at least 8 hours apart. Do not combine doses or make up missed doses. Take once a day, or divided into two doses at least 8 hours apart for smoking cessation.

·        Avoid or limit the use of alcohol while on this drug. Seizures can occur if these are combined.

·        May be used with transdermal nicotine; most effective for smoking cessation if combined with behavioral support program.

·        You may experience these side effects: Dizziness, lack of coordination, tremor (avoid driving or performing tasks that require alertness); dry mouth (use frequent mouth care; suck sugarless lozenges); headache, insomnia (consult with care provider if these become a problem; do not self-medicate); nausea, vomiting, weight loss (eat frequent small meals).

·        Report dark urine, light-colored stools; rapid or irregular heart beat; hallucinations; severe headache or insomnia; fever, chills, sore throat.

Adverse effects in Italic are most common; those in Bold are life-threatening.