Levodopa therapy and the risk of malignant melanoma.

To evaluate the use of levodopa therapy in patients with Parkinson's disease and malignant melanoma. A MEDLINE search (January 1966-September 1999) of English-language articles was conducted. Key search terms included levodopa, melanoma, and Parkinson's disease; 34 case reports were identified. Carbidopa/levodopa continues to be a mainstay in the treatment of Parkinson's disease. Since the late 1970s, a warning has appeared in the prescribing literature for levodopa regarding the risk of activating malignant melanoma. An evaluation was conducted of the case reports in which a causal relationship between levodopa and melanoma was suggested. There is an unlikely association between levodopa and induction or exacerbation of malignant melanoma.