Ustekinumab (Stelara)
Fully human IgG1 monoclonal antibody targeting the p40 subunit shared by interleukins IL-12 and IL-23. Weight-based SC dosing for psoriasis (45 mg if <=100 kg, 90 mg if >100 kg) at weeks 0 and 4 then every 12 weeks; weight-based IV induction then SC maintenance for Crohn's and UC. Biphasic PK with terminal half-life ~3 weeks. SC bioavailability ~57%. Generally well tolerated; modest serious-infection signal.
Projected serum levels — 90 mg, custom (shown daily)
Maintenance schedule: 90 mg custom (shown daily) (subcutaneous).
Loading schedule: 270 mg on day 1, then 90 mg custom (shown daily) — reaching therapeutic levels sooner.
Modeled steady state after ~65 days: peak ≈ 1.6k mg, trough ≈ 1.6k mg body load. Population-based estimate over 121 days for a 90 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.
Key facts
- Category
- Biologic
- Route modeled
- Subcutaneous
- Model confidence
- inferred
- Half-life
- 21 days
- Common dose
- 90 mg
- Suggested maximum
- 90 mg/day
- Reference dose range
- 45–90 mg (single dose)
- Suggested cadence
- custom (shown daily)
- Validated against
- 45 mg sc — Cmax 8.3 mg/L at 168 h
Research behind this entry
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Population pharmacokinetics of ustekinumab in patients with moderate to severe plaque psoriasis
Population PK analysis describing biphasic disposition, ~3-week terminal half-life, weight-dependent clearance, and SC bioavailability ~57%.
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Efficacy and safety of ustekinumab, a human interleukin-12/23 monoclonal antibody, in patients with psoriasis (PHOENIX 2)
Pivotal PHOENIX 2 trial establishing ustekinumab 45 mg and 90 mg q12w efficacy for moderate-to-severe plaque psoriasis.
2 published studies referenced in the app, each with a plain-language summary.