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Hydroxychloroquine (Plaquenil)

Disease-Modifying Antirheumatic Drug (DMARD)prescriptionoral · inferred

Antimalarial and DMARD for rheumatoid arthritis and systemic lupus erythematosus. Extremely long terminal half-life (~40-50 days) due to extensive tissue uptake. Steady state requires months. Requires periodic ophthalmologic monitoring for retinal toxicity.

Projected serum levels — 200 mg, twice daily

Hydroxychloroquine (Plaquenil)
Hydroxychloroquine (Plaquenil) modeled serum levels, 200 mg twice daily over 121 days Population-based pharmacokinetic estimate. Steady state reached after approximately 88 days. 0 5k 10k 15k 20k Day 0 Day 30 Day 60 Day 90 Day 121 Time on a regular schedule ≈ steady state · day 88
Hydroxychloroquine (Plaquenil) modeled serum levels with a loading dose of 600 mg, then 200 mg twice daily The first dose is larger so levels approach steady state faster. 0 5k 10k 15k 20k Day 0 Day 30 Day 60 Day 90 Day 121 Time on a regular schedule

Maintenance schedule: 200 mg twice daily (oral).

Loading schedule: 600 mg on day 1, then 200 mg twice daily — reaching therapeutic levels sooner.

Modeled steady state after ~88 days: peak ≈ 15.2k mg, trough ≈ 15.1k mg body load. Population-based estimate over 121 days for a 200 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Disease-Modifying Antirheumatic Drug (DMARD)
Route modeled
Oral
Model confidence
inferred
Half-life
40 days
Common dose
200 mg
Suggested maximum
800 mg/day
Reference dose range
200–800 mg (single dose)
Suggested cadence
twice daily
Validated against
400 mg oral — Cmax 0.13 mg/L at 3.3 h

Documented interactions

  • danger
    4-MMC (Mephedrone) + Hydroxychloroquine (Plaquenil) CYP inhibition

    Hydroxychloroquine (Plaquenil) reversible_inhibitor of CYP2D6 predicted to change 4-MMC (Mephedrone) AUC by ~2.27x

  • danger
    6-APB (Benzofury / 6-(2-aminopropyl)benzofuran) + Hydroxychloroquine (Plaquenil) CYP inhibition

    Hydroxychloroquine (Plaquenil) reversible_inhibitor of CYP2D6 predicted to change 6-APB (Benzofury / 6-(2-aminopropyl)benzofuran) AUC by ~3.33x

  • danger
    Amphetamine (Adderall) + Hydroxychloroquine (Plaquenil) CYP inhibition

    Hydroxychloroquine (Plaquenil) reversible_inhibitor of CYP2D6 predicted to change Amphetamine (Adderall) AUC by ~2.11x

  • danger
    Atomoxetine (Strattera) + Hydroxychloroquine (Plaquenil) CYP inhibition

    Hydroxychloroquine (Plaquenil) reversible_inhibitor of CYP2D6 predicted to change Atomoxetine (Strattera) AUC by ~2.68x

  • danger
    Carbamazepine (Tegretol) + Hydroxychloroquine (Plaquenil) CYP induction

    Carbamazepine (Tegretol) inducer of CYP3A4 predicted to change Hydroxychloroquine (Plaquenil) AUC by ~0.49x

  • danger
    Dextromethorphan (DXM) + Hydroxychloroquine (Plaquenil) CYP inhibition

    Hydroxychloroquine (Plaquenil) reversible_inhibitor of CYP2D6 predicted to change Dextromethorphan (DXM) AUC by ~2.47x

Serum checks 159 modeled interaction pairings for hydroxychloroquine (plaquenil) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. A randomized trial of hydroxychloroquine in early rheumatoid arthritis: the HERA Study HERA Study Group · American Journal of Medicine, 1995 DOI

    Randomized double-blind placebo-controlled trial showing hydroxychloroquine significantly improved synovitis, pain, and physical disability over 36 weeks in recent-onset rheumatoid arthritis.

  2. Hydroxychloroquine compared with placebo for rheumatoid arthritis: a randomized controlled trial Clark P et al. · Annals of Internal Medicine, 1993 DOI

    Six-month double-blind RCT demonstrating hydroxychloroquine produced clinically and statistically significant improvements over placebo in joint score, pain, and grip strength in RA.

  3. Hydroxychloroquine in systemic lupus erythematosus: overview of current knowledge Dima A et al. · Therapeutic Advances in Musculoskeletal Disease, 2022 DOI

    Comprehensive review establishing hydroxychloroquine as a cornerstone of SLE therapy, with evidence for reduced flares, organ damage accrual, thrombotic events, and improved survival.

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