Clinical Information

Hydroxychloroquine is used to treat symptoms of acute or chronic rheumatoid arthritis and lupus erythematosus. Adult doses range from 400 mg/week for suppressive therapy to 1200 mg/day for acute malaria attacks. Typical daily doses of 200 to 600 mg are used for lupus and rheumatoid diseases. Hydroxychloroquine has a long terminal elimination half-life in blood (>40 days), which exceed those in plasma. The oral bioavailability averages 79%.

Hydroxychloroquine accumulates in several organs, especially melanin-containing retina and skin. Mild to moderate overdose can result in gastrointestinal effects (ie, nausea, vomiting, and abdominal pain), headache, visual/hearing disturbances, and neuromuscular excitability. Acute hepatitis, cardiotoxicity, and retinopathy may occur with therapeutic doses. The effects of over dosage with hydroxychloroquine include headache, drowsiness, visual disturbances, convulsions, cardiovascular collapse and respiratory arrest. Toxic retinopathy has also been associated with higher doses and longer duration of use.