|
|
Anti-Parasitic MedicationsA parasite is an organism that lives on or inside another organism (called a host) and causes harm. Humans can play "host" to over 100 different kinds of parasites ranging from microscopic to long tapeworms. Parasites generally enter the body through the mouth or skin. Parasites that enter through the mouth are swallowed and can remain in the intestine or burrow through the intestinal wall and invade other organs. Most skin parasites are tiny insects or worms that burrow into the skin and make their home there. Some parasites live in the skin for part of their life cycle; others would be permanent residents. Scabies is a mite infestation that produces tiny reddish bumps and itching. Scabies is caused by the itch mite Sarcoptes scabei. The infestation spreads easily from person to person on physical contact, often spreading though an entire household. The hallmark of scabies is intense itching, which is usually worse at night. The burrows of the mites are often visible as very thin linesup to 1/2 inch long. The burrows can be anywhere on the body except the face. Common sites are the webs between the fingers and toes, the wrists, ankles, buttocks. Treatment options for scabies include permethrin cream, lindane, benzyl benzoate, crotamiton lotion and cream, and sulfur. These mediactions are called scabicides. Permethrin (Elimite) 5% cream can be used to cure scabies. CDC recommends this agent as a first-line treatment. Permethrin is the treatment of choice for children and for pregnan women. According to the Cochrane Review that focused on treating scabies, topical permethrin is considered the most effective treatment, more effective than lindane and crotamiton3. Even after successful treatment, itching may persist for up to 2 weeks because of a continued allergic reaction to the mite bodies, which remain in the skin for a while. Today the use of lindane as a treatment for lice or scabies is considered outmoded due to increasing resistance, lack of efficacy, and toxicity to the nervous system. In many countries this medication is no longer available. Sulfur in petrolatum is the oldest treatment for scabies, however not FDA approved for this use. Sulfur is one of the few scabicidal treatments that may be used safely in very small children and in pregnant women. However, this medicine is messy, malodorous, stains clothes, and requires repeat applications. Crotamiton 10% cream or lotion (Eurax) is approved by the US FDA for the treatment of scabies in adults. This agent is not approved for use in children. Ivermectin (Mectizan, Stromectol) is an oral medication used to treat other parasites. It is currently not approved by the FDA for the treatment of scabies, but there are studies that show that it is effective. This oral medicine may be convenient for people with skin conditions that should not use topical medications. Anthelmintics (anti-worm medications) Parasitic helminthic infections are caused by parasitic worms of the helminth class. The most common worm parasites include hookworm, pinworm, threadworm, whipworm, tapeworm, and Ascaris lumbricoides (common roundworm). Anthelmintics (also called antihelminthics) are medications that work by killing the worms. Antihelminthic medicines are prescription only drugs. Virtually all of the worm infections can be treated with one of anthelmintics currently available: albendazole (Albenza), mebendazole (Vermox), diethylcarbamazine (Hetrazan), ivermectin (Stromectol), praziquantel (Biltricide), and thiabendazole (Mintezol)1. These drugs have broad spectrum coverage with high cure rates. Mebendazole and albendazole are benzimidazole derivatives. These agents are most effective against intestinal roundworms (e.g. pinworms), but are contraindicated during the first trimester of pregnancy. Mebendazole and albendazole are useful in single doses for various intestinal worm infections as they have a broad spectrum coverage. Cure rate with single doses of albendazole and mebendazole is about 88-95% for ascariasis2. For hookworm infections, albendazole is more effective than mebendazole. Cure rates for trichuriasis with single-dose treatment are low (28% for albendazole and 36% for mebendazole). Albendazole is active against a wider range of worms than mebendazole, being effective against strongyloidiasis, toxocariasis, hydatid disease, and cysticercosis. Therefore albendazole is the drug of choice in mixed worm infections. Praziquantel is the medication of choice for schistosomiasis. It is also effective for intestinal tapeworm infections (taeniasis) and neurocysticercosis. References
Last updated: October, 2009 |
|