Pharmacotherapy of ectoparasitic infections

Epizoonoses such as scabies, lice and cimicosis are common, vexing disorder s that occur worldwide, Historically, many treatment modalities have been e mployed in the management of these disorders, and most of the drugs describ ed in this review are of historical interest and no longer recommended or i n widespread use because of their wide spectrum of adverse effects, More re cently, reports documenting resistance against various antiectoparasite dru gs, complicated and severe courses of the diseases, and adverse effects of drug therapy have prompted the development of new treatment strategies and drugs for optimal disease management. Because the strategies currently recommended for the treatment of ectoparas ites differ worldwide, this review proposes a rational approach to selectin g the best therapeutic agent by comparing the pharmacokinetics, pharmacodyn amics, drug efficacy and adverse effects. A literature search of the curren tly Internet accessible libraries PubMed, Medline and Ideal library, of cit ations of articles found there, and from communications with the Federal In stitute for Drugs and Medical Devices, Germany, was conducted based on this approach. One major observation of this literature search is that permethrin is the t reatment of choice for lice and scabies in the US and in Great Britain, whe reas lindane is still recommended for scabies in most other European countr ies because of its longer-standing record of effectiveness. Although permet hrin has not yet been proven to be more effective than lindane in treating infections with these ectoparasites, it currently appears to have the best efficacy versus safety profile of topical treatments for scabies and lice. Ivermectin is a newer oral drug for the treatment of ectoparasites, which h as been used with great success in the treatment of onchocercosis and other endoparasites. Although ivermectin appears to be a promising drug, its rol e in the treatment of ectoparasitic infections will be clarified as more st udy data become available. Finally, it is important to emphasise the clinical aspects of ectoparasite therapy and that providing the patient with optimal instructions on the use of topical therapeutics is of great importance in avoiding adverse effects and assuring complete removal of the ectoparasite, thereby avoiding the de velopment of drug-resistance.