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Anthelmintic Drugs

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Anthelmintic Drugs

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Anthelmintic Drugs

  1. 1. Anthelmintics Prepared by, Mr. Namdeo Shinde M. Pharm SATARA COLLEG OF PHARMACY, SATARA .(Maharashtra) India-415004
  2. 2. Anthelmintics. (Anti = against, helminthes = worms) Vermicides : Drugs that kill worms Vermifuges :Drugs that expel the worms from the body by 1) Peristaltic movement of intestine, or 2) Cathartic and purgative action. Characters of ideal anthelmintics: 1) Orally active. 2) Effective in single dose. 3) Inexpensive. 4) Wide safety margin between toxicity to worm and toxicity to
  3. 3. :Classification of Helminthes Phylum: Nemathelminthes. Class: Nematodes (true round worms) I) Intestinal Nematodes: 1) Round worms as Ascaris. 2) Hookworms as Ancylostoma. 3) Pinworms as Oxyuris. 4) Whipworms as Trichuris. 5) Thread worms as Strongyloids. 6) Enterobius Vermicularis. II) Tissue Nematodes:Filaria. Phylum: Platyhelminthes ( flatworms) Class: Termatodes ( Flukes ) 1) Liver flukes: .2) Blood flukes: 3) Intestinal flukes: Fasciola Hepatica. Fasciola Gigantica Schistosoma haematobium. Heterophyes heterophyes. Class: Cestodes ( Tapeworms ) Beef tapeworm:Taenia saginata. Pork tapeworm:Taenia solium. Dwarf tapeworm:Hymenolepis nana. Schistosoma mansoni.
  4. 4. A] Drugs active on Nematodes: I] Chlorinated compounds: CCl4 , tetrachloroethylene. II] Piperazine derivatives: piperazine citrate, diethylcarbamazine citrate. III] Benzimidazole derivatives: Thiabendazole, Mebendazole, Flubendazole, and Albendazole. IV] Vinylpyrimidine derivatives: Pyrantel pamoate. V] Dyes:( cyanine dyes ): Pyrivinium pamoate VI] Imidazothiazoles: Levimasole.
  5. 5. I] Chlorinated compounds: CCl4 , tetrachloroethylene. CCl4 Must be followed by purgative to remove dead worms and excess drug. Its side effects are 1) liver necrosis. 2) not used during pregnancy, otherwise make liver and kidney damage to the fetus tetrachloroethylene. MOA: Cause irritation to the worm tissue. Used in Treatment of roundworm infestations. Less toxic than CCl4, but all halogenated hydrocarbons cause liver and kidney degeneration II] Piperazine derivatives: piperazine citrate, diethylcarbamazine citrate
  6. 6. Mode of action: 1) Inhibition of certain enzyme: which is fumarate reductase system of the worm thereby interfering with an important energy source. 2) Inhibition of the cell division: inhibit nematode cell division in the metaphase by interfering with the microtubule assembly 3) They have high affinity for tubulin, the precursor protein, necessary for microtubule synthesis. 4) They make irreversible blockade of glucose uptake by susceptible helminthes, so depletion of glycogen stored within the parasite leads to decrease in ATP, which is responsible for survival and reproduction in helminthes.
  7. 7. No need for purgative use after oral administration **all of them have broad spectrum anthelmintic activity mainly against intestinal nematodes, but, 1) Thiabendazole also used in treatment of cutaneous larva migrans. 2)Mebendazole , flubendazole and albendazole effective in some cestode worms. side effects of mebendazole and albendazole:  GIT side effects in normal doses.  Liver impairment, bone marrow depression in high doses.  Should not given in pregnancy as teratogenic can cross the placenta
  8. 8. Imidazothiazoles. Levamisole. 1) act as Depolarizing neuromuscular blocking agent and as above in pyrantel pamoate. 2) potent stereospecific inhibitor of fumarate reductase in various nematodes, such inhibition causes contraction in helminthes, followed by tonic paralysis, subsequent elimination of the worm. ** used for treatment of round worm as Ascariasis, and hook worm as ancylostomiasis.** Cmpletely absorbed from the GIT, The levo isomer is the only active one.
  9. 9. Niclosamide. 1)interfere with helminthes metabolism where it inhibits mitochondrial oxidative phosphorylation, inhibit respiration, block glucose uptake by the cestode. 2)2)after initial attack of the drug,helminthes ( taenia solium ) become highly sensitive to the proteolytic enzymes of the host intestine, undergo partial digestion. ** the drug of choice in treatment of most tapeworm infestations. (cestodes) such as Taenia saginata, Taenia solium, Hymenolepis nana. ** very important note: In case of Taenia solium, ( pork tapeworm):laxative should be given within 1-2 hours after drug use to expel the dead worms and to avoid cysticercosis [ as the drug is not active against the larval form (cystcerci)].This cysticerci results from release of live ova from worm segments damaged by the drug and migrate to the stomach
  10. 10. Niclosamide. 1)interfere with helminthes metabolism where it inhibits mitochondrial oxidative phosphorylation, inhibit respiration, block glucose uptake by the cestode. 2)2)after initial attack of the drug,helminthes ( taenia solium ) become highly sensitive to the proteolytic enzymes of the host intestine, undergo partial digestion. ** the drug of choice in treatment of most tapeworm infestations. (cestodes) such as Taenia saginata, Taenia solium, Hymenolepis nana. ** very important note: In case of Taenia solium, ( pork tapeworm):laxative should be given within 1-2 hours after drug use to expel the dead worms and to avoid cysticercosis [ as the drug is not active against the larval form (cystcerci)].This cysticerci results from release of live ova from worm segments damaged by the drug and migrate to the stomach

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