Levamisole as basic treatment of rheumatoid arthritis: longterm evaluation.

We evaluated longterm levamisole treatment of 201 rheumatoid patients. Fifty-nine patients in their 1st yr of treatment were not analyzed; of the remaining 142, 69 (49%) still took levamisole with benefit. Levamisole was stopped in 32 patients (22%) for inefficacy and for reversible adverse reactions in 37 (26%). Leukotoxic side-effects were the commonest cause of withdrawal (23 patients = 16%). Since June 1977, we administer levamisole on a 1 d/wk schedule (150 mg), with determination of white blood cells 10 h after intake to detect high-risk patients for agranulocytosis. With disease exacerbation during treatment or lack of response after 6 months, the drug is given on a 2nd non-consecutive day. Since June 1977, cases of agranulocytosis have not been observed. Allergic vasculitis did not occur with a 1 d/wk schedule. The absence of nephrotoxicity and hepatotoxicity is stressed. Only 4 patients (3%) were lost to follow-up. Comparison is made with longterm use of gold and D-penicillamine. We conclude that levamisole is a useful slow acting antirheumatic drug.