Calcium-entry blockers-induced parkinsonism: possible role of inherited susceptibility.

The risk of developing drug-induced parkinsonism (DIP) has been related to a number of factors but it remains up to now poorly defined. The aim of this survey has been to evaluate retrospectively the possible role of inherited components in 25 patients with parkinsonism induced by chronic exposure to the calcium-entry blockers cinnarizine and flunarizine. The finding of higher occurrence of a positive family history for Parkinson's disease (PD) and/or essential tremor (ET) and of higher frequency of secondary cases with PD and/or ET among close relatives of the patients as compared to age-matched controls, suggests the involvement of genetic susceptibility in developing this drug-induced disorder. DIP could be regarded as a multifactorial disease process resulting from potential neurotoxicity of drugs on a background of inherited predisposition.