Drug-induced myoclonus: a French pharmacovigilance database study

Abstract

Various drugs have been reported to induce myoclonus. However, this adverse event is not well known because of the difficult diagnosis and the lack of pharmaco-epidemiological or controlled studies. As far as we know, there are only case reports. In the literature, antiparkinsonian medications, antipsychotics, antidepressants, anesthetics, opiates and anti-infectious drugs have been reported in the occurrence of myoclonus. In a French pharmacovigilance database study, only 423 reports (0.2%) involved drug-induced myoclonus. The median age of patients was 55 years and 10% of these patients had a concomitant neurological disease. Only 16% of these reports had a strong imputability score (likely). The most frequently involved drugs were anti-infectious (15%), antidepressants (15%), anxiolytics (14%), and opiates agents (12%). Fifty-six percent of these reports were classified as serious adverse event. Concerning outcome, most patients (84%) recovered without sequels.