Drug-Induced Movement Disorders PDF

Preface

A drug is a single chemical that forms the active ingredient of a medicine. Medicines may also contain other substances designed to deliver a drug in a stable, convenient form for the patient. Despite these differences in definition, the terms ‘‘drug'' or ‘‘medicine'' are usually used interchangeably in the medical world. While many drugs serve to benefit mankind, other drugs are addictive, harmful, or dangerous and have limited medical use. Most drugs are double-edged swords with potential to do both good and harm. The harm may be as trivial as a mild hangover from diazepam or life threatening as in cases of sudden death following an injection of penicillin. Somewhere in the middle are movement disorders induced by drugs.

Drug-induced movement disorders are encountered by physicians in every discipline of medicine, but especially by psychiatrists and neurologists. The introduction of neuroleptics in the 1950s provides an early example of drugs that were soon associated with abnormal movements, both acutely and in a delayed (tardive) fashion. Subsequently, hyperkinetic movement disorders became a major clinical problem in advanced levodopa-treated Parkinson's disease patients. In addition to these examples, many other classes of drugs commonly used by neurologists and psychiatrists have been associated with the drug-induced movement disorders. Despite a more sophisticated science of drug design today, newer drugs are frequently associated with inducing movement disorders in susceptible patients.

This book provides authoritative reviews on the subject of iatrogenic movement disorders. Experts in psychiatry and neurology have been enlisted to review movement disorders due to dopamine-blocking agents since these drugs remain in extensive use. Selective serotonin reuptake inhibitors (SSRIs), discussed in Chapter 11, are one of the most commonly prescribed drugs associated with abnormal movements. Movement disorders due to both older and newer antiepileptics are also discussed. Chapter 6 reviews therapeutic options for drug-induced movement disorders including botulinum toxin therapy and replacing conventional neuroleptics with newer, atypical agents. Chapter 9 discusses several new antipsychotics introduced recently and more are on the horizon. There is increasing understanding of the complex basal ganglia circuitry and Chapter 13 is devoted to this topic to better understand the pathophysiology of movement disorders.

As new drugs are developed the spectrum of drug-induced movement disorders will undoubtedly widen. We hope that this volume will provide a platform for building further knowledge in the evaluation and treatment of patients with drug-induced movements.