ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
Antimalarial — Lupus / Dermatoses Pregnancy: Compatible with pregnancy — used throughout pregnancy in lupus; reduces flare rate in SLE during pregnancy; benefits outweigh risks

Hydroxychloroquine

Brand names: Plaquenil

Adult dose

Dose: 200–400 mg/day (max 5 mg/kg/day ideal body weight — retinal toxicity threshold)
Route: Oral
Frequency: Once or twice daily
Max: 5 mg/kg/day actual body weight (never exceed 400 mg/day)
Used for cutaneous lupus erythematosus (CLE — discoid, subacute, systemic), dermatomyositis, and porphyria cutanea tarda. Also used in SLE with skin manifestations. Slow onset (2–3 months). Dose must not exceed 5 mg/kg/day to minimise retinal toxicity.

Paediatric dose

Dose: 5 mg/kg/day mg/kg
Route: Oral
Frequency: Once daily
Max: 5 mg/kg/day (max 400 mg/day)
BNFc: used in childhood lupus — specialist paediatric rheumatology/dermatology input. Annual ophthalmology assessment mandatory.

Dose adjustments

Renal

Use with caution in severe renal impairment — accumulation risk

Hepatic

Use with caution in hepatic impairment

Paediatric weight-based calculator

BNFc: used in childhood lupus — specialist paediatric rheumatology/dermatology input. Annual ophthalmology assessment mandatory.

Clinical pearls

  • Retinal toxicity: cumulative dose and daily dose >5 mg/kg/day are key risk factors — annual ophthalmology review (fundoscopy + visual field testing + SD-OCT) mandatory from year 5 of treatment (earlier if risk factors)
  • MHRA recommendation: do not exceed 5 mg/kg/day based on actual body weight — previous guidance used ideal body weight, now updated
  • CLE: hydroxychloroquine improves photosensitivity, rash, and systemic disease activity; reduces lupus flares and progression to SLE
  • Sunscreen and sun avoidance are essential adjuncts in photosensitive CLE — hydroxychloroquine reduces but does not eliminate photosensitivity
  • Slow onset 6–8 weeks: do not assess for treatment failure before 3–6 months of therapy
  • G6PD screen before starting — haemolysis risk in deficient patients

Contraindications

  • Pre-existing maculopathy
  • G6PD deficiency (relative — haemolysis risk)
  • Hypersensitivity to 4-aminoquinolines
  • Porphyria (caution — though used in PCT)

Side effects

  • Retinal toxicity / maculopathy (irreversible — 'bull's eye' maculopathy — dose and duration dependent)
  • GI disturbance (nausea, diarrhoea)
  • Headache
  • Skin pigmentation
  • Cardiomyopathy (rare — conduction defects)
  • Haemolytic anaemia (G6PD deficiency)

Interactions

  • Digoxin — increased digoxin levels
  • Antidiabetics — enhanced hypoglycaemic effect
  • Immunosuppressants — additive immunosuppression
  • QT-prolonging drugs — additive QTc risk

Monitoring

  • Annual ophthalmology (fundoscopy + SD-OCT + visual fields)
  • FBC
  • LFTs
  • Renal function
  • ECG (if cardiac history)

Reference: BNFc; BNF 90; BNFc; MHRA Drug Safety Update (2018) Hydroxychloroquine dose; RCOphth Hydroxychloroquine Guidelines 2020; BAD CLE Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Pathways