Mepacrine

Information for general practitioners

Updated 2026

Mepacrine is an uncommonly used medicine in SLE, usually used if difficult skin rashes. It is very similar to Hydroxychloroquine so follow same guidance.

Dosage

50-100 mg three times per week, often with hydroxychloroquine on the alternate days

Monitoring procedure

Blood monitoring not required

Cautions

Avoid in psoriasis

Side effects

Common effects are in bold type.

Mucocutaneous

pruritis erythematous rash seen after treatment commenced.
blue-black pigmentation of skin

Haematological

thrombocytopenia
agranulocytosis (very rare)

Gastrointestinal

nausea
diarrhoea
abdominal cramps

Ocular

cycloplegia
keratopathy (reversible)
irreversible retinopathy/maculopathy
photophobia – advise sunglasses in bright light

Other

headache
bleaching of skin/hair
proximal myopathy
peripheral neuropathy

Hospital contacts

Secretaries 01387 241776

Helpline 01387 241095 (answering machine) - Rheumatology Nurse Specialists

Department of Rheumatology doctors via Switchboard 01387 246246/RMS Advice Request

Last reviewed: 12/03/2026

Next review date: 12/03/2028

Author(s): Lucy Moran.