Wellbutrin SR (bupropion hydrochloride sustained-release) is a widely prescribed antidepressant belonging to the aminoketone class, distinct from commonly used selective serotonin reuptake inhibitors (SSRIs). It is specifically formulated to provide sustained delivery of bupropion, maintaining stable plasma concentrations over a 12-hour dosing interval. This medication is indicated for the treatment of major depressive disorder (MDD) in adults and is also approved for the prevention of seasonal affective disorder (SAD). Its unique neurochemical profile, primarily acting as a norepinephrine-dopamine reuptake inhibitor (NDRI), offers a valuable therapeutic alternative, particularly for patients who experience undesirable effects with serotonergic agents, such as sexual dysfunction or weight gain.

Features

• Active ingredient: Bupropion hydrochloride (100 mg or 150 mg per tablet)
• Dosage form: Sustained-release (SR) oral tablets
• Mechanism of action: Norepinephrine-dopamine reuptake inhibitor (NDRI)
• Dosing frequency: Twice daily (approximately 8 hours apart)
• Bioavailability: Approximately 87% relative to immediate-release formulation
• Half-life: Average 21 hours (±9 hours) for bupropion; active metabolites have longer half-lives
• Excretion: Primarily renal (87%) and fecal (10%)

Benefits

• Reduces symptoms of major depressive disorder, including low mood, anhedonia, and fatigue
• Lower incidence of sexual dysfunction compared to SSRIs and SNRIs
• Minimal weight gain; some patients may experience weight loss
• Does not commonly cause sedation, making it suitable for daytime use
• May improve concentration and energy levels in certain patients
• Approved for the prevention of seasonal affective disorder (SAD)

Common use

Wellbutrin SR is primarily prescribed for the treatment of major depressive disorder (MDD) in adults. Its sustained-release formulation allows for twice-daily dosing, providing continuous symptom control throughout the day. Clinicians may also consider it off-label for attention-deficit/hyperactivity disorder (ADHD), though this use is not FDA-approved. The medication is particularly valuable for patients who have experienced sexual side effects or significant weight gain with other antidepressants. It is not indicated for bipolar depression unless combined with a mood stabilizer due to the risk of inducing manic episodes.

Dosage and direction

The recommended starting dose for Wellbutrin SR is 150 mg once daily in the morning. After at least 3 days, the dose may be increased to 150 mg twice daily, with doses taken at least 8 hours apart. The maximum recommended dose is 400 mg per day, given as 200 mg twice daily. Doses should not exceed 150 mg in a single administration. Tablets should be swallowed whole and not crushed, chewed, or divided, as this would compromise the sustained-release properties. Administration with food may minimize potential gastrointestinal upset. Dose adjustments are necessary in patients with hepatic or renal impairment.

Precautions

Patients should be monitored for worsening depression, suicidality, or unusual changes in behavior, particularly during initial treatment or dose adjustments. Wellbutrin SR lowers the seizure threshold in a dose-dependent manner; caution is advised in patients with history of seizure, head trauma, or eating disorders. Blood pressure monitoring is recommended due to potential hypertensive effects. Use with caution in patients with hepatic or renal impairment, requiring dose reduction. May cause angle-closure glaucoma in susceptible individuals. Patients should avoid alcohol consumption during treatment. Not recommended during pregnancy unless potential benefits outweigh risks.

Contraindications

Wellbutrin SR is contraindicated in patients with seizure disorder or history of epilepsy. It must not be used in patients with current or prior diagnosis of bulimia or anorexia nervosa due to increased seizure risk. Contraindicated in patients undergoing abrupt discontinuation of alcohol or sedatives. Should not be used concomitantly with monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing MAOI therapy. Hypersensitivity to bupropion or any component of the formulation prohibits use. Not recommended for patients with untreated hypertension or unstable cardiovascular disease.

Possible side effects

Common side effects (≥1%) include dry mouth, nausea, insomnia, headache, constipation, tremor, excessive sweating, and dizziness. Less frequently (0.1-1%), patients may experience tinnitus, blurred vision, tachycardia, rash, or weight changes. Serious adverse effects include seizures (dose-dependent), hypertension, allergic reactions, and psychiatric symptoms such as agitation, anxiety, or hallucinations. Approximately 28% of patients in clinical trials discontinued treatment due to adverse effects, most commonly neuropsychiatric symptoms or rash. Side effect profile differs from SSRIs, with lower incidence of sexual dysfunction but higher incidence of insomnia and agitation.

Drug interaction

Wellbutrin SR interacts significantly with drugs metabolized by CYP2D6 isoenzyme, potentially increasing concentrations of beta-blockers, antipsychotics, and certain antidepressants. Concurrent use with MAOIs is contraindicated due to risk of hypertensive crisis. May potentiate effects of levodopa and amantadine. Drugs that lower seizure threshold (antipsychotics, antidepressants, tramadol) may increase seizure risk. Caution with drugs affecting hepatic metabolism (carbamazepine may decrease bupropion levels). May interact with systemic corticosteroids. Nicotine replacement therapy may enhance adverse effects.

Missed dose

If a dose is missed, patients should take it as soon as remembered unless it is almost time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Patients should not take double or extra doses to make up for a missed dose, as this increases the risk of seizures and other adverse effects. If multiple doses are missed, patients should contact their healthcare provider for guidance on resuming therapy, as dose adjustment may be necessary.

Overdose

Wellbutrin overdose presents a medical emergency requiring immediate attention. Symptoms may include seizures, hallucinations, sinus tachycardia, ECG changes (prolonged QRS or QTc), and loss of consciousness. Fatal outcomes have been reported with doses exceeding 4,500 mg. Management includes gastric lavage if presented early, activated charcoal, and supportive care with continuous ECG monitoring. Seizures should be treated with benzodiazepines; barbiturates or phenytoin may be necessary for refractory cases. Acidification of urine is not recommended as it may increase seizure risk. There is no specific antidote for bupropion overdose.

Storage

Store at controlled room temperature (20-25°C or 68-77°F) with excursions permitted between 15-30°C (59-86°F). Keep in original container, tightly closed, and protect from light and moisture. Keep out of reach of children and pets. Do not store in bathroom cabinets due to humidity fluctuations. Discard any medication that has expired or shows signs of deterioration (discoloration, crumbling). Do not flush medications down the toilet; dispose of properly through medication take-back programs.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Wellbutrin SR is available by prescription only and should be used under appropriate medical supervision. Individual response to medication may vary. Patients should consult their healthcare provider for diagnosis and treatment recommendations. The complete prescribing information should be reviewed before initiating therapy. Not all possible uses, interactions, or adverse effects are listed here.

Reviews

Clinical studies demonstrate Wellbutrin SR’s efficacy in major depressive disorder, with response rates comparable to other antidepressants. In a 8-week randomized controlled trial (n=348), 62% of patients receiving bupropion SR showed significant improvement in Hamilton Depression Rating Scale scores versus 38% for placebo. Patients frequently report improved energy levels and fewer sexual side effects compared to SSRIs. However, some users note initial side effects including insomnia and agitation, which often diminish with continued treatment. The sustained-release formulation is generally preferred over immediate-release for improved tolerability and convenience. Long-term studies support maintenance of antidepressant efficacy with continued therapy.