Antimalarial drugs for rheumatoid arthritis.

Chloroquine and hydroxychloroquine effectively suppress rheumatoid arthritis with a superior benefit to risk ratio. Controlled studies demonstrate moderate efficacy in about 70 percent of patients. High-grade suppression is seen in 15 percent and partial suppression in 55 percent. The dropout rate for poor efficacy is 30 percent and for side effects 3 to 7 percent. Most studies show antimalarials to be almost equivalent to chrysotherapy in potency. Antimalarials are indicated for active rheumatoid arthritis not optimally controlled with nonsteroidal anti-inflammatory drugs and for all cases of progressive disease. Therapy is continued indefinitely. Safe use of these drugs depends on daily dosage. With the single exception of late stage retinopathy, other adverse effects are fully reversible. Strict adherence to three tested safety rules virtually eliminates retinopathy and prevents loss of vision: (1) limit the daily dosage: chloroquine 3.5 to 4.0 mg/kg per day or hydroxychloroquine 6.0 to 6.5 mg/kg per day based on lean body weight; (2) subject the patient to an annual ocular examination to age 65, twice annually thereafter; (3) adjust treatment for pharmacokinetic variables. The lower risk and nearly comparable efficacy make antimalarials first choice among remittive drugs.