What are the side effects of Wellbutrin XL (bupropion) 150 mg?

Side Effects of Wellbutrin XL 150 mg

The most common side effects of Wellbutrin XL 150 mg include weight loss, loss of appetite, dry mouth, insomnia, anxiety, agitation, nausea, headache, dizziness, tremor, constipation, and increased sweating. 1

Most Frequently Reported Adverse Effects

Common Side Effects (Occurring in General Use)

• Weight loss and decreased appetite are among the most prominent effects, with approximately 23% of patients losing more than 5 pounds in clinical trials 1
• Insomnia affects approximately 11-20% of patients, particularly when doses are taken late in the day 1
• Dry mouth is a frequently reported complaint 1
• Nausea occurs commonly and is one of the most frequent reasons for treatment discontinuation 2
• Headache and dizziness are reported regularly 1
• Agitation and anxiety occur in 2-7% of patients, typically appearing shortly after treatment initiation 1
• Tremor (shakiness) is a common neurologic side effect 1
• Constipation can occur and may be severe in some cases 3
• Increased sweating is frequently noted 1

Gastrointestinal Effects

• Constipation can range from mild to severe, with documented cases requiring surgical intervention when combined with other risk factors 3
• Nausea and vomiting are common early in treatment and represent the most frequent cause of medication discontinuation in efficacy studies 2

Cardiovascular Effects

• Tachycardia (fast heartbeat) occurs in some patients 1
• Hypertension can develop, and in some cases may be severe enough to require acute treatment 1

Serious but Less Common Adverse Effects

Seizure Risk

• Seizures occur in approximately 0.1% (1 in 1,000) of patients taking therapeutic doses of Wellbutrin XL 300 mg daily 4
• The risk increases with higher doses and in patients with predisposing factors 1
• Seizures can occur with delayed onset, up to 24 hours after overdose situations 5

Neuropsychiatric Effects

• Suicidal thoughts or behavior may emerge, particularly in young adults during the first 1-2 months of treatment 4
• Hallucinations, delusions, paranoia, and confusion have been reported in some patients 1
• Agitation, hostility, and unusual behavioral changes can occur 1

Allergic Reactions

• Severe hypersensitivity reactions including rash, hives, angioedema, and difficulty breathing occur in approximately 1 in 1,000 to 1 in 10,000 patients 4
• Urticaria and angioedema can develop even after several weeks of treatment 6
• Stevens-Johnson syndrome and anaphylactic shock have been reported rarely 1

Sexual Side Effects

• Bupropion has significantly lower rates of sexual dysfunction (approximately 8%) compared to SSRIs like fluoxetine or sertraline (18-30%) 2, 7, 4
• This makes bupropion a preferred option when sexual side effects are a primary concern 7

Metabolic Effects

• Weight loss is more common than weight gain, with 14-23% of patients losing more than 5 pounds 1
• Only 3-11% of patients experience weight gain of more than 5 pounds 1

Special Population Considerations

Pregnancy and Breastfeeding

• Bupropion is present in breast milk and has been detected in nursing infants, though usually at very low levels 8
• Two case reports document seizures in breastfed infants exposed to bupropion through breast milk 8
• A small increased risk of cardiovascular malformations (left ventricular outflow tract obstruction and ventricular septal defects) has been associated with first-trimester exposure, though confounding cannot be ruled out 8

Factors That Increase Side Effect Risk

Conditions That Lower Seizure Threshold

• Eating disorders (anorexia nervosa or bulimia) are absolute contraindications 1
• History of head injury or seizure disorder contraindicates use 1
• Brain tumors or stroke increase seizure risk 1
• Abrupt discontinuation of alcohol or benzodiazepines raises seizure risk 1

Drug Interactions

• Monoamine oxidase inhibitors (MAOIs) are contraindicated within 14 days of bupropion use 1
• Multiple medications can increase the risk of seizures or other serious side effects when combined with bupropion 1

Monitoring Recommendations

• Intensive monitoring for neuropsychiatric symptoms (suicidal ideation, agitation, irritability, unusual behavioral changes) should occur during the first 1-2 weeks and continue for at least the first 2 months of therapy 4
• Blood pressure monitoring is important, as hypertension can develop during treatment 1
• Assessment for allergic reactions should be ongoing, as severe reactions can occur even after weeks of treatment 6

Common Pitfalls to Avoid

• Taking doses late in the day significantly increases insomnia risk; the medication should be taken in the morning, and if using twice-daily dosing, the second dose must be before 3 PM 4
• Crushing, cutting, or chewing tablets releases the medication too quickly and increases seizure risk 1
• Abruptly stopping alcohol consumption while on bupropion increases seizure risk 1
• Missing the diagnosis of sleep disorders: if excessive daytime sleepiness develops on bupropion, screen for obstructive sleep apnea or other primary sleep disorders rather than attributing it solely to the medication 4