Hydroxychloroquine Dose Calculator by Weight
Estimates the ophthalmology safety ceiling of 5 mg/kg/day of actual body weight (AAO 2016 revised guidelines), checks a current dose against it, and illustrates 200 mg tablet schedules — with eye-screening context.
Calculator
Where the 5 mg/kg ceiling comes from
The American Academy of Ophthalmology first issued hydroxychloroquine screening guidance in 2002 and revised it in 2011 — then revised it again in 2016 (Marmor et al., Ophthalmology 2016;123(6):1386–1394). The big change:
- 2011: max 6.5 mg/kg/day of ideal body weight (from old animal studies suggesting the drug avoids fat tissue).
- 2016: max 5 mg/kg/day of actual body weight — because a large human study (Melles & Marmor, JAMA Ophthalmology 2014, 2,361 patients) showed real weight predicts retinal toxicity far better than ideal weight, and found toxicity in about 7.5% of long-term users — roughly triple earlier estimates.
Quick reference
- 50 kg → max 250 mg/day
- 60 kg → max 300 mg/day
- 70 kg → max 350 mg/day
- 80 kg → max 400 mg/day
Eye-screening context
Retinal toxicity is the main long-term risk of hydroxychloroquine: it can be irreversible and may keep progressing even after the drug is stopped, so screening — not just dosing — is the safeguard.
- Within the first year — baseline ophthalmologic exam after starting HCQ (dilated fundus exam, macular OCT, automated visual fields).
- Annually after 5 years — yearly screening for standard-risk patients on continued therapy.
- Annually from the start — for high-risk patients: kidney disease, pre-existing macular disease, or concurrent tamoxifen use.
Asian ancestry is noted separately in the guideline: toxicity can appear more peripherally, so wider visual-field testing (24-2 or 30-2) is recommended. Ask your eye doctor about it if relevant.
Scope boundary
- This tool is: an educational arithmetic estimator for the ophthalmology safety ceiling of chronic hydroxychloroquine dosing (5 mg/kg/day of actual body weight, AAO 2016).
- Not a prescription or diagnosis tool. Indication (lupus, rheumatoid arthritis, malaria), kidney function, other medicines, and disease activity can all change the real-world dose — only the prescriber weighs those.
- Not for malaria dosing. Acute malaria treatment and prophylaxis follow entirely different weight-based regimens; this ceiling applies to chronic use.
- Not a pediatric antibiotic tool. For weight-based pediatric dosing of a different drug class, see our pediatric amoxicillin dosage estimator — the math and safety rules do not transfer.
Frequently asked questions
What is the maximum safe hydroxychloroquine dose?
Per the American Academy of Ophthalmology 2016 revised guidelines, the maximum recommended dose for retinal safety is 5 mg/kg per day of actual body weight. Doses above that were associated with sharply higher retinopathy risk in the large Kaiser Permanente study behind the revision. An educational ceiling — discuss your dose with your doctor.
Why actual body weight instead of ideal body weight?
The 2011 guidance used 6.5 mg/kg of ideal body weight, based on old animal studies. The 2014 Melles & Marmor study of ~2,361 patients showed actual body weight predicts toxicity better, so the 2016 revision switched — the old rule systematically overdosed thin patients.
What is the max dose for a 70 kg adult?
350 mg per day (70 × 5 mg/kg). With 200 mg tablets, prescribers illustrate this as 200 mg daily or 200/400 mg on alternate days (average 300 mg/day) — illustrative patterns only; the prescriber decides.
How do 200 mg tablets fit the 5 mg/kg limit?
Tablets come in 200 mg, so the exact mg/kg number is rounded into schedules whose average daily dose stays at or below the ceiling. The calculator shows which illustrative schedules fit — never self-adjust.
When should eye screening start?
Baseline exam within the first year of starting HCQ, then annual screening after 5 years. High-risk patients (kidney disease, prior macular disease, tamoxifen use) are advised annual screening from the start.
What raises the risk of retinal toxicity?
Dose above 5 mg/kg/day, long duration (risk climbs after 5–10 years), high cumulative dose, kidney disease, pre-existing retinal disease, and concurrent tamoxifen. Toxicity can be irreversible and progress after stopping — hence dosing within the ceiling plus regular screening.
Is Plaquenil dosing the same?
Yes — Plaquenil is the brand name of hydroxychloroquine sulfate, so the same 5 mg/kg/day actual-weight ceiling applies. Beware calculators still using the outdated 2011 rule.
Can the dose exceed 400 mg per day?
Rarely for chronic use; the 5 mg/kg ceiling usually lands well below 400 mg for most adults (350 mg at 70 kg, 300 mg at 60 kg). Higher doses are specialist-supervised exceptions. Do not increase a dose on your own.
Is hydroxychloroquine dosed differently for COVID-19?
Major randomized trials (RECOVERY, WHO Solidarity) found no meaningful benefit of hydroxychloroquine for COVID-19, and current guidelines do not recommend it outside clinical trials. Be skeptical of sources promoting HCQ dosing for COVID-19 without acknowledging how the evidence changed.
What if my current dose is above 5 mg/kg?
Do not stop or change it yourself — abrupt changes can flare lupus or rheumatoid arthritis. Discuss the finding promptly with your prescribing doctor and ask about ophthalmology screening.
Does kidney disease change the limit?
Kidney disease is a major risk factor (slower clearance) and triggers annual eye screening from the start. This calculator does not adjust for kidney function — prescribers often target lower doses there.
How long can hydroxychloroquine be taken?
Many patients take it for years with low risk (roughly 1–2% in the first decade) when kept within 5 mg/kg/day with screening. Risk rises with duration (~20% after 20 years in studies), so annual screening after 5 years is the key safeguard. Ongoing use is a decision for you and your doctor.
Free tool by NRTechStudio