Hydroxychloroquine
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Dosing and administration[3]
Oral, with food. Doses are expressed as hydroxychloroquine sulfate (a 200 mg tablet equals 155 mg base). Dose by body weight to minimise retinal toxicity and arrange ophthalmologic screening.
| Indication | Starting dose | Titration and maximum |
|---|---|---|
| Rheumatoid arthritis and lupus | Product monograph: initial 400 to 600 mg daily, reduced to a maintenance of 200 to 400 mg daily once responding (usually by 4 to 12 weeks). Most adults are maintained on 200 to 400 mg daily. | Dose to weight. The monograph cites up to 6.5 mg/kg of lean (ideal) body weight; current ophthalmology guidance (AAO 2016), followed in rheumatology, recommends not exceeding 5 mg/kg of ACTUAL body weight. For many adults this means 400 mg/day or less. |
Onset. Onset over about 4 to 12 weeks.
Renal adjustment. Use with caution and consider lower doses in renal impairment (reduced clearance increases retinal toxicity risk).
Hepatic. Use with caution in hepatic impairment or with other hepatotoxic drugs.
Weight-based dosing: the product monograph cites up to 6.5 mg/kg lean body weight, whereas the 2016 American Academy of Ophthalmology recommendation adopted in rheumatology is not to exceed 5 mg/kg actual body weight; the more conservative guideline figure is used here to reduce retinopathy risk.
Monitoring
- Baseline ophthalmologic examination within the first year, then annual screening after 5 years of use (earlier with risk factors: dose above the weight-based threshold, renal impairment, tamoxifen, or use beyond 5 years).
- Screening uses automated visual fields and spectral-domain OCT.
- Retinal toxicity is largely irreversible, so the emphasis is on prevention through weight-based dosing and on early detection.
Contraindications
- Known hypersensitivity to 4-aminoquinolines.
- Pre-existing retinopathy or maculopathy.
- Caution in G6PD deficiency (hemolysis) and with QT-prolonging drugs or cardiac disease.
Key interactions
- Tamoxifen: increases retinal toxicity risk.
- QT-prolonging drugs: additive QT effect.
- May raise digoxin and cyclosporine levels; can enhance the effect of hypoglycaemic agents.
Clinical notes
How it is used in lupus
Strongly recommended as routine therapy for people with SLE unless contraindicated, and conditionally continued indefinitely even in sustained remission. The long-term average daily dose goal is at or below 5 mg/kg/day to reduce retinal toxicity.[1]
Common side effects
Generally well tolerated. Gastrointestinal upset and cutaneous effects are the more common issues; retinal toxicity is uncommon but cumulative with long-term use. Described from background clinical knowledge; reconcile with the product monograph.
Tests and monitoring
CBC with differential, AST, ALT, and creatinine at baseline and periodically. Retinal screening at baseline, then annually no later than 5 years after starting. Baseline ECG, and subsequently if at risk for QTc prolongation from concomitant drugs or cardiac risk factors. In kidney disease, consider dose adjustment for low GFR, since renal impairment raises retinal-toxicity risk.[1, 2]
Important cautions
Generally continued through pregnancy and lactation and often actively encouraged in SLE; reproductive-health guidance is maintained on the pregnancy record. Report visual changes promptly. Non-categorical framing; monograph to be reconciled.
References
- Sammaritano LR, Askanase A, Bermas BL, et al. 2025 American College of Rheumatology (ACR) Guideline for the Treatment of Systemic Lupus Erythematosus. Arthritis Care Res (Hoboken). 2025. doi:10.1002/acr.25690 https://doi.org/10.1002/acr.25690
- Sammaritano LR, Askanase A, Bermas BL, et al. 2024 American College of Rheumatology (ACR) Guideline for the Screening, Treatment, and Management of Lupus Nephritis. Arthritis Care Res (Hoboken). 2025;77(9):1045-1065. doi:10.1002/acr.25528 https://doi.org/10.1002/acr.25528
- PLAQUENIL (hydroxychloroquine sulfate tablets) Product Monograph. Health Canada authorized product monograph (Sanofi). https://pdf.hres.ca/dpd_pm/00069324.PDF