Monoamine oxidase inhibitors and sleep movements

Drug-induced myoclonus: frequency, mechanisms and management

Myoclonus is a sudden, abrupt, brief, 'shock-like' involuntary movement caused by muscular contractions ('positive myoclonus') or a sudden brief lapse of muscle contraction in active postural muscles ('negative myoclonus' or 'asterixis'). Various disorders can cause myoclonus including neurodegenerative and systemic metabolic disorders and CNS infections. In addition, myoclonus has been described as an adverse effect of some drugs. Level II evidence is available to indicate that levodopa, cyclic antidepressants and bismuth salts can cause myoclonus, while there is less robust evidence to associate numerous other drugs with the induction of myoclonus. The pharmacological mechanisms responsible for this adverse effect are not well established, although increased serotonergic transmission may be involved in the induction of myoclonus by several drugs. Drug-induced myoclonus usually resolves after withdrawal of the offending drug, but in some cases specific treatments are needed.

Polysomnography in drug development

Polysomnography in drug development is used to detect desirable and undesirable effects of drugs on normal and disturbed sleep. Although this method is essential for the approval of new hypnotic drugs, it is quite often neglected in the development of drugs that show unwanted side effects on normal sleep. In this review, the requirements for qualified polysomnography are described, the strong and weak points of the method are discussed, and its importance for the drug development process is pointed out.