Bupropion Immediate Release (Wellbutrin)

Antidepressantprescriptionoral · predicted

Immediate-release bupropion tablet. It produces an earlier peak than SR or XL and is normally divided across the day to limit peak-related seizure risk.

Projected serum levels — 100 mg, twice daily

Bupropion Immediate Release (Wellbutrin)
Bupropion Immediate Release (Wellbutrin) modeled serum levels, 100 mg twice daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 3 days. 0 12.5 25 37.5 50 Day 0 Day 4 Day 7 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 3
Bupropion Immediate Release (Wellbutrin) modeled serum levels with a loading dose of 300 mg, then 100 mg twice daily The first dose is larger so levels approach steady state faster. 0 12.5 25 37.5 50 Day 0 Day 4 Day 7 Day 11 Day 15 Time on a regular schedule

Maintenance schedule: 100 mg twice daily (oral).

Loading schedule: 300 mg on day 1, then 100 mg twice daily — reaching therapeutic levels sooner.

Modeled steady state after ~3 days: peak ≈ 41.5 mg, trough ≈ 30.4 mg body load. Population-based estimate over 15 days for a 100 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Antidepressant
Route modeled
Oral
Model confidence
predicted
Half-life
21 h
Common dose
100 mg
Suggested maximum
450 mg/day
Reference dose range
75–450 mg (single dose)
Suggested cadence
twice daily

Research behind this entry

  1. A sustained-release bupropion for pharmacologic relapse prevention after smoking cessation: a randomized, controlled trial Hays JT et al. · Annals of Internal Medicine, 2001 DOI

    RCT found sustained-release bupropion significantly delayed smoking relapse, with point-prevalence abstinence rates of 55% at 12 months versus 42% for placebo.

  2. Bupropion-SR, sertraline, or venlafaxine-XR after failure of SSRIs for depression (STAR*D) Rush AJ et al. · New England Journal of Medicine, 2006 DOI

    Landmark STAR*D trial found bupropion was as effective as sertraline and venlafaxine as switch therapy after SSRI failure, with the advantage of less sexual dysfunction.

2 published studies referenced in the app, each with a plain-language summary.