A comparison of low dose levamisole and penicillamine in rheumatoid arthritis.

Levamisole (150 mg once weekly) was compared with penicillamine (250 mg daily) in a single blind independent observer study in 28 patients with rheumatoid arthritis over twelve months. Fifty percent (8/16) of patients stopped levamisole, five within three months of starting, while only two of twelve stopped penicillamine. In those patients able to tolerate treatment for twelve months, both regimens produced a significant and comparable reduction in disease activity, with the onset of action of penicillamine occurring at three months compared with six to nine months for levamisole. Radiological progression of disease occurred in both groups. Levamisole in low dose may improve parameters of disease activity in rheumatoid arthritis but poor patient tolerance, slow onset of action and failure to prevent radiological progression limit its usefulness.