Anthelmintic Drugs

Anthelmintic Drugs

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  Anthelmintics B. PHARM SEMESTERVI (3rd Year 2nd Sem.) S.SEETARAM SWAMY, M.Pharm., Assoc. Professor, Dept. of Pharmaceutical Chemistry, E-mail: [email protected] Copyrights @ www.pharmawisdom.co.in
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  Anthelmintics are drugsthat either kill (vermicide) or expel (vermifuge) infesting helminths. Almost 350 species of helminths have been found in humans, and most colonise the gastrointestinal tract (G.I.T). Humans are primary host for helminth infections, in the sense that they harbour the sexually mature form that reproduces. Eggs or larvae then pass out of the body and infect the secondary (intermediate) host. Helminthiasis is more common in developing countries with poorer personal and environmental hygiene. They harm the host by depriving him of food, causing blood loss, injury to organs, intestinal or lymphatic obstruction and by secreting toxins. Helminthiasis is rarely fatal, but is a major cause of ill health. Anthelminthic Drugs Copyrights @ www.pharmawisdom.co.in
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  The helminths comprisetwo major Groups: 1. Nemathelminths (Nematodes - roundworms) 2. Platyhelminths (Flatworms) The latter group is subdivided into the two groups a) Trematode (Flukes) b) Cestodes (Tapeworms) Classification of Helminths Copyrights @ www.pharmawisdom.co.in
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  Classification of Anthelminticsbased on chemical structure : A) Piperazines: Examples: Diethylcarbamazine citrate (DEC), Piperazine citrate B) Benzimidazoles: Examples: Albendazole, Mebendazole, Thiabendazole. C) Heterocyclics: (Quinolines and Isoquinolines) Examples: Oxamniquine , Praziquantel D) Natural Products: Example: Ivermectin E) Amide (Salicylanilide): Example: Niclosamide. Classification of Anthelmintic Drugs Copyrights @ www.pharmawisdom.co.in
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  Piperazines Piperazine is anorganic compound that consists of a six-membered ring containing two opposing nitrogen atoms. Piperazine compounds mediate their anthelmintic action by generally paralyzing parasites, allowing the host body to easily remove or expel the invading organism. Example: Diethylcarbamazine citrate (DEC) Commonly used antinematodal drug against only Ascaris and Oxyuris worms in man and animals. Not recommended for other helminthes infestation. Administered as citrate or phosphate salts. Drug of choice for treatment of Filariasis Mechanism of action: DEC acts as a γ-aminobutyric acid (GABA) agonist effect so it prevents neural transmission in the worm causing muscular paralysis and expelling of the worms alive. Copyrights @ www.pharmawisdom.co.in
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  Synthesis of Diethylcarbamazinecitrate Copyrights @ www.pharmawisdom.co.in
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  These are versatileAnthelmintic agents particularly effective against gastrointestinal nematodes. These are highly effective against ascaris, enterobius, trichuris and hookworm infections. The agents most widely employed for reducing morbidity are the benzimidazole (BZ) Anthelmintics, either Albendazole (ALBENZA and ZENTEL) or Mebendazole (VERMOX). ATM – Albendazole, Thiabendazole, Mebendazole Benzimidazoles (BZ) Copyrights @ www.pharmawisdom.co.in
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  The first ofthis class, Thiabendazole, was discovered in 1961 and subsequently a number of further Benzimidazoles were introduced as broad spectrum Anthelmintics. Thiabendazole effective against threadworm, cutaneous larva migrans, and early stage of trichinosis. Thiabendazole has anti-inflammatory, analgesic and antipyretic actions. Mebendazole is a synthetic benzimidazole that has a wide spectrum of Anthelmintic activity and a low incidence of adverse effects. It is a drug of choice in the treatment of infections by whipworm eggs, pinworm, hookworms, and roundworm. Albendazole, a broad-spectrum oral Anthelmintic agent. It is the drug of choice for treatment of hydatid disease and cysticercosis. It is also used in the treatment of pinworm and hookworm, round worm, whip worm, and thread worm infections. Mechanism of action: Benzimidazoles probably acts by inhibiting microtubule synthesis. Its bind with parasite ‘β-tubulin’ and inhibit its polymerization. In addition Benzimidazole probably blocks glucose uptake in parasite and depletes its glycogen stores. Copyrights @ www.pharmawisdom.co.in
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  Synthesis of Mebendazole Copyrights@ www.pharmawisdom.co.in
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  Oxamniquine is atetrahydroquinoline that is effective in S. mansoni infections. Oxamniquine is used only to treat schistosomiasis caused by the worm Schistosoma mansoni. Oxamniquine may associate with an irreversible inhibition of the nucleic acid metabolism of the parasites. Oxamniquine It is a Novel Anthelmintic. Active against Schistosomes ,Trematodes & Cestodes. Mech. of action: Acts by causing leakage of IC Ca from the membrane, causing Contracture & Paralysis in worm loses its grip in GIT & expelled out. Praziquantel Copyrights @ www.pharmawisdom.co.in
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  It is aMacrocylic lactone antibiotics. Acts as GABA agonist & Cause paralysis of parasite. Ivermectin is the drug of choice for the treatment of onchocerciasis (river blindness) caused by Onchocerca volvulus. Ivermectin : It is a Salicylanilide derivative. It is used to treat tapeworm infestations. This includes diphyllobothriasis, hymenolepiasis, and taeniasis. Mechanism of Action: Inhibiting oxidative phosphorylation in mitochondria and interfering with anaerobic generation of ATP by the tapeworm Niclosamide Copyrights @ www.pharmawisdom.co.in
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