Wellbutrin Side Effects
Wellbutrin (bupropion) commonly causes dry mouth, insomnia, nausea, headache, dizziness, agitation, and tremor, with serious risks including seizures (especially at doses >450 mg/day or in predisposed patients), neuropsychiatric events (suicidal thoughts, psychosis, mania), hypertension, and cardiovascular complications in overdose. 1
Common Side Effects (Occurring in ≥5% of Patients)
The most frequently reported adverse effects based on FDA labeling and clinical guidelines include 2, 1:
- Gastrointestinal: Dry mouth (most common), nausea, constipation, abdominal pain
- Neurological: Headache, dizziness, insomnia, tremor, agitation
- Psychiatric: Anxiety, nervousness
- Cardiovascular: Palpitations, tachycardia
- Other: Sweating, tinnitus, pharyngitis, myalgia, anorexia, urinary frequency, rash
Nausea and vomiting are the most common reasons for treatment discontinuation in clinical trials 3.
Serious Adverse Events and Black Box Warnings
Suicidal Thoughts and Behaviors
The FDA mandates a black box warning for increased risk of suicidal thinking and behavior in children, adolescents, and young adults (through age 24) within the first few months of treatment. 1 The pooled absolute risk is approximately 1% with antidepressants versus 0.2% with placebo, yielding a number needed to harm of 143 4. However, a 2016 multicenter RCT (EAGLES trial) found that neuropsychiatric adverse events with bupropion were not significantly increased relative to nicotine patches or placebo in patients with or without psychiatric disorders 5.
Close monitoring is essential, especially:
- Within the first 1-2 weeks of treatment initiation 3
- Following dose adjustments
- In patients with history of depression or mental health problems 1
Seizure Risk
Bupropion is contraindicated in patients with seizure disorders, and the seizure risk is dose-dependent. 1 Key considerations:
- Estimated seizure risk: approximately 0.1% at therapeutic doses 6
- Risk increases significantly at doses >450 mg/day 1
- In overdose cases, seizures occur in approximately one-third of patients 1
- One patient developed status epilepticus in a series of 476 inadvertent extra-dose cases 7
Absolute contraindications for seizure risk 2, 5:
- Current or prior seizure disorder
- Bulimia or anorexia nervosa (predisposes to seizures)
- Abrupt discontinuation of alcohol, benzodiazepines, barbiturates, or antiepileptic drugs
- Brain metastases or stroke
- Conditions that lower seizure threshold
Neuropsychiatric Adverse Events
Beyond suicidality, bupropion can cause 1:
- Psychosis: Hallucinations, delusions, paranoia, feeling confused
- Mania/Hypomania: Greatly increased energy, severe insomnia, racing thoughts, reckless behavior, unusually grand ideas, excessive happiness or irritability, talking more or faster than usual
- Behavioral activation/agitation: Aggression, hostility, depression, anxiety, panic
These symptoms may occur when beginning treatment, after several weeks, or even after stopping bupropion 1. Patients should discontinue Wellbutrin and contact their healthcare provider immediately if these symptoms develop.
Cardiovascular Effects
Hypertension: Bupropion can cause significant blood pressure elevations 1. Monitor blood pressure before initiating treatment and periodically during therapy. Risk may be higher when combined with nicotine replacement therapy 1.
In overdose, serious cardiovascular complications include 1, 8, 9:
- Cardiogenic shock requiring mechanical circulatory support
- Ventricular dysrhythmias
- QRS widening (odds ratio 3.01 for adverse cardiovascular events)
- QTc prolongation (odds ratio 1.76 for adverse cardiovascular events)
- Cardiac arrest and death
A 2023 study of 4,640 bupropion exposures found that age, seizures, QRS widening, and QTc prolongation were independently associated with adverse cardiovascular events 8.
Other Serious Adverse Events
- Sexual dysfunction: Notably, bupropion has a significantly lower rate of sexual adverse events compared to SSRIs like fluoxetine or sertraline 3
- Angle-closure glaucoma: Can occur in patients with untreated anatomically narrow angles 1
- Hepatotoxicity: Rare but reported 3
- Allergic reactions: Occur at approximately 3% rate 6
- False-positive drug tests: Can cause false-positive urine tests for amphetamines 1, 10
Dose-Related Considerations
In a retrospective review of 476 patients who inadvertently took extra doses 7:
- 38.4% experienced at least one adverse effect
- Doses were significantly higher in patients with adverse effects (p = 0.045)
- Seizures occurred at 0.8% (twice the rate of therapeutic dosing)
- Clinical outcomes: 61.6% no effect, 27.7% minor effect, 10.3% moderate effect, 0.4% major effect
Special Populations and Contraindications
Absolute contraindications 1:
- Seizure disorder
- Current or prior bulimia or anorexia nervosa
- Abrupt discontinuation of alcohol, benzodiazepines, barbiturates, or antiepileptic drugs
- Concurrent MAOI use (within 14 days)
- Known hypersensitivity to bupropion
Use with caution in 2, 11, 12:
- Uncontrolled hypertension
- History of suicidal ideation
- Hepatic impairment (reduce dose to 150 mg every other day in moderate-to-severe impairment) 1
- Renal impairment (consider dose reduction)
- Patients taking tamoxifen (drug interaction)
- Closed-angle glaucoma
Rare but Notable Adverse Events
A 2024 large-scale FAERS database analysis identified some new potential adverse reactions 10:
- Stool analysis abnormal
- Suspected suicide
- Encephalopathy neonatal
- Hyponatremic coma
- ECG QRS complex prolongation
- Positive amphetamine drug screens (relatively common)
One case report described acute colonic pseudo-obstruction following massive bupropion overdose, likely due to anticholinergic properties at supratherapeutic levels 13.
Clinical Monitoring Recommendations
Initiate monitoring within 1-2 weeks of starting therapy 3:
- Assess for suicidal thoughts, mood changes, behavioral activation
- Monitor blood pressure
- Evaluate for seizure risk factors
- Screen for mania/hypomania symptoms
- Continue regular monitoring, especially after dose adjustments
Educate patients to immediately report 1:
- New or worsening depression, anxiety, agitation
- Suicidal thoughts or behaviors
- Unusual changes in behavior or mood
- Seizures
- Severe hypertension symptoms
- Psychotic symptoms