Switching from Wellbutrin 75 mg to Wellbutrin XR 150 mg
When switching from immediate-release bupropion 75 mg to extended-release (XR) 150 mg, make the switch directly by discontinuing the 75 mg dose and starting 150 mg XR the next morning, as the FDA labeling states to give the same total daily dose when possible when switching formulations. 1
Direct Switching Strategy
The FDA-approved approach is straightforward: stop the immediate-release formulation and start the XR formulation at an equivalent or higher dose the following day. 1 Since you're moving from 75 mg to 150 mg XR, this represents both a formulation change and a dose increase, which is appropriate as 150 mg once daily is the recommended starting dose for bupropion XR. 1
Specific Implementation Steps
Discontinue the 75 mg immediate-release dose and begin 150 mg XR the next morning. 1
Administer the XR formulation in the morning to minimize insomnia risk, as bupropion has activating properties. 2
The tablet must be swallowed whole and not crushed, divided, or chewed, per FDA labeling. 1
May be taken with or without food. 1
Dose Titration Considerations
The 150 mg XR dose serves as both the starting dose and a therapeutic dose for major depressive disorder. 1 After 4 days at 150 mg XR, the dose may be increased to the target dose of 300 mg once daily if clinically indicated. 1
For patients requiring more gradual titration (such as older adults or those on multiple medications), an alternative approach would be starting at 37.5 mg every morning and increasing by 37.5 mg every 3 days as tolerated. 2 However, this is not necessary for most patients switching from 75 mg immediate-release.
Critical Monitoring Parameters
Monitor for seizure risk factors, as bupropion lowers the seizure threshold and the risk increases with doses above 300 mg daily (maximum 450 mg for XR formulation). 2, 1
Watch for neuropsychiatric adverse effects, particularly in patients younger than 24 years, including increased agitation, anxiety, and suicidal ideation. 2
Monitor blood pressure, as bupropion should be avoided in patients with uncontrolled hypertension. 2
Common adverse effects include insomnia, headache, dry mouth, nausea, and anxiety, with insomnia and dry mouth occurring significantly more frequently than placebo. 3 These are generally transient and often resolve without intervention. 3
Special Population Adjustments
For patients with moderate to severe hepatic impairment (Child-Pugh score 7-15), the maximum dose is 150 mg every other day, not daily. 1
For patients with renal impairment (GFR <90 mL/min), reduce the total daily dose by half. 2, 1
For older adults, consider starting with lower doses (37.5 mg) and titrating more gradually to minimize adverse reactions. 2
Common Pitfalls to Avoid
Do not exceed 450 mg daily of the XR formulation to minimize seizure risk. 2, 1
Avoid use in patients with seizure disorders, eating disorders (bulimia or anorexia nervosa), or those abruptly discontinuing alcohol or benzodiazepines, as these significantly increase seizure risk. 2, 1
Do not initiate within 14 days of MAOI discontinuation or start an MAOI within 14 days of stopping bupropion. 1
If insomnia develops, ensure the dose is taken in the morning and not later in the day. 2 If a second dose were needed (with SR formulation), it should be given before 3 PM. 2