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Anthelmintic Drugs 
Dr. S. Parasuraman 
Faculty of Pharmacy, 
AIMST University, 
Malaysia.
Anthelmintic Drugs 
• Infections with helminths, or parasitic worms, affect more than two billion 
people worldwide. 
• An...
Geographic distribution of intestinal helminths
Geographic distribution of coinfection with 
helminths 
Source: World map showing the geographic distribution of coinfecti...
Effect of helminth-induced immunity on 
infections with microbial pathogens 
TTisisssuuee d daammaaggee 
Induce the releas...
Relative incidence of helminth infections 
worldwide. 
Reference: Goodman & Gilman's The Pharmacologic Basis of Therapeuti...
Tissue helminths
Soil Transmitted Helminth Infections 
The major STH infections, which include ascariasis, 
trichuriasis, and hookworm infe...
Anthelmintic Drugs 
• Classification of anthelmintics based on chemical 
structure 
– Piperazines: Diethylcarbamazine citr...
Anthelmintic Drugs 
Worm Drug of Choice Alternative Drugs 
Roundworms: Ascaris lumbricoides Mebendazole, Albendazole, Pyra...
Mebendazole 
• Mebendazole is a synthetic benzimidazole that has a 
wide spectrum of anthelmintic activity and a low 
inci...
Mebendazole 
• Pharmacokinetics: 
– Absorption of mebendazole from intestines is minimal. 
– Less than 10% of orally admin...
Mebendazole 
• Adverse effects: 
– Well tolerated even by patient in poor health. 
– Mild nausea, vomiting, diarrhea, and ...
Albendazole 
• Albendazole, a broad-spectrum oral anthelmintic agent. 
• It is the drug of choice for treatment of hydatid...
Albendazole 
• Clinical Uses: 
– Albendazole is administered on an empty stomach when used against 
intraluminal parasites...
Albendazole 
• Pharmacokinetics: 
– Albendazole is erratically absorbed after oral administration, but 
absorption is enha...
Thiabendazole 
• Thiabendazole effective against threadworm, 
cutaneous larva migrans, and early stage of trichinosis. 
• ...
Pyrantel pamoate 
• Pyrantel pamoate, along with mebendazole is effective in the 
treatment of infections caused by roundw...
Piperazine 
• Piperazine causes hyperpolarization of Ascaris 
muscle by GABA agonist action (opening of chloride 
channels...
Diethyl carbamazine citrate (DEC) 
• DEC developed in 1948, and its is the first drug for 
filariasis. 
• DEC absorbed aft...
Diethyl carbamazine citrate (DEC) 
• Diethylcarbamazine has a highly selective effect on 
microfilariae (Mf) at a dose of ...
Ivermectin 
• Is the drug of choice for the treatment of onchocerciasis (river 
blindness) caused by Onchocerca volvulus a...
Niclosamide 
• MOA: Inhibiting oxidative phosphorylation in 
mitochondria and interfering with anaerobic 
generation of AT...
Drug for fascioliasis 
• Bithionol: 
– Used for the treatment of fascioliasis and cerebral 
paragonimiasis. 
– Bithionol i...
Thank you
Echinococcus multilocularis 
Hydatid disease 
Back
Anthelmintic Drugs 
Roundworms 
Hookworm 
Pinworm 
Threadworm 
Whipworm
Anthelmintic Drugs 
Filaria 
Wuchereria bancrofti, 
Brugia malayi 
Guinea worm 
Dracunculus medinensis 
Tapeworms
Neurocysticercosis 
Back
Anthelmintic drugs
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Anthelmintic drugs

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Anthelmintic drugs

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Anthelmintic drugs

  1. 1. Anthelmintic Drugs Dr. S. Parasuraman Faculty of Pharmacy, AIMST University, Malaysia.
  2. 2. Anthelmintic Drugs • Infections with helminths, or parasitic worms, affect more than two billion people worldwide. • Anthelmintics are drugs that either kill (vermicide) or expel (vermifuge) infesting helminths. Helminthiasis is prevalent globally (1/3rd of world's population harbours them). • Helminthiasis is more common in developing countries with poorer personal and environmental hygiene. • In the human body, g.i.t. is the abode of many helminths, but some also live in tissues, or their larvae migrate into tissues. • 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.
  3. 3. Geographic distribution of intestinal helminths
  4. 4. Geographic distribution of coinfection with helminths Source: World map showing the geographic distribution of coinfection with helminths together with tuberculosis, malaria and/or HIV infection of adults. (Nature Immunology 2013;14:1118–26)
  5. 5. Effect of helminth-induced immunity on infections with microbial pathogens TTisisssuuee d daammaaggee Induce the release of cytokine alarmins (IL- 33, IL-25 and TSLP) Induce the release of cytokine alarmins (IL- 33, IL-25 and TSLP) Promote the production of cytokines, eosinophils and basophils Promote the production of cytokines, eosinophils and basophils Excretory secretory molecules produced and worms can shut down DC synthesis of proinflammatory cytokines and promote DC production of the immunoregulatory molecules Excretory secretory molecules produced and worms can shut down DC synthesis of proinflammatory cytokines and promote DC production of the immunoregulatory molecules Bone marrow precursors Bone marrow precursors CD4+ cells Increased Treg Cells, TH2 effector cells, regulatory TH1 cells. Decreased TH1 and TH17 effector cells. Source: World map showing the geographic distribution of coinfection with helminths together with tuberculosis, malaria and/or HIV infection of adults. (Nature Immunology 2013;14:1118–26)
  6. 6. Relative incidence of helminth infections worldwide. Reference: Goodman & Gilman's The Pharmacologic Basis of Therapeutics - 11th Ed. (2006)
  7. 7. Tissue helminths
  8. 8. Soil Transmitted Helminth Infections The major STH infections, which include ascariasis, trichuriasis, and hookworm infection, are among the most prevalent infections in developing countries. Because STH worm burdens are higher in school-aged children than in any other single group.
  9. 9. Anthelmintic Drugs • Classification of anthelmintics based on chemical structure – Piperazines: Diethylcarbamazine citrate (DEC), Piperazine citrate. – Benzimidazoles: Albendazole, Mebendazole, Thiabendazole. – Heterocyclics: Oxamniquine, Praziquantel. – Natural products: Ivermectin, Avermectin. – Vinyl pyrimidines: Pyrantel, Oxantel. – Amide: Niclosamide. – Nitro derivative: Niridazole. – Imidazo thiazole: Levamisole.
  10. 10. Anthelmintic Drugs Worm Drug of Choice Alternative Drugs Roundworms: Ascaris lumbricoides Mebendazole, Albendazole, Pyrantel. Piperazine, Levamisole, Ivermectin. Hookworm: Ancylostoma duodenale Pyrantel, Mebendazole, Albendazole. Levamisole. Hookworm: Necator americanus Mebendazole, Albendazole. Pyrantel. Pinworm: Enterobius vermicularis Pyrantel, Mebendazole, Albendazole. Piperazine Threadworm: Strongyloides stercoralis Ivermectin Albendazole Whipworm: Trichuris trichiura Mebendazole Albendazole Whipworm: Trichinella spiralis Albendazole Mebendazole Filaria Wuchereria bancrofti, Diethyl carbamazine, Ivermectin Albendazole Brugia malayi Guinea worm Dracunculus medinensis Metronidazole Mebendazole Tapeworms Taenia saginala Taenia solium Hymenolepis nana Neurocy sticercosis Praziquantel, Niclosamide Praziquantel Praziquantel Albendazole Albendazole Niclosamide, Albendazole Niclosamide, Nitazoxanide Praziquantel Hydatid Disease Echinococcus granulosus E. multilocularis Albendazole Albendazole Mebendazole
  11. 11. Mebendazole • 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. • Mechanism of action: – Mebendazole probably acts by inhibiting microtubule synthesis. Its bind with parasite ‘β-tubulin’ and inhibit its polymerization. In addition mebendazole probably blocks glucose uptake in parasite and depletes its glycogen stores. – Efficacy of the drug varies with gastrointestinal transit time, with intensity of infection, and perhaps with the strain of parasite.
  12. 12. Mebendazole • Pharmacokinetics: – Absorption of mebendazole from intestines is minimal. – Less than 10% of orally administered mebendazole is absorbed. The absorbed drug is protein-bound (> 90%), rapidly converted to inactive metabolites (primarily during its first pass in the liver), and has a half-life of 2-6 hours. – 75 – 90% of oral dose passed in the faeces. • Dose: – 100 mg chewable tablet. – 100 mg/5ml suspension. – 100 mg tablet. – Mebendazole is one of the preferred drugs for treatment of multiple infestations and is more effective than albendazole in trichuriasis.
  13. 13. Mebendazole • Adverse effects: – Well tolerated even by patient in poor health. – Mild nausea, vomiting, diarrhea, and abdominal pain have been reported infrequently. Rare side effects, usually with high-dose therapy, are hypersensitivity reactions (rash, urticaria), agranulocytosis, alopecia, and elevation of liver enzymes. – Mebendazole is teratogenic in animals and therefore contraindicated in pregnancy. – It should be used with caution in children younger than 2 years of age because of limited experience and rare reports of convulsions in this age group.
  14. 14. Albendazole • 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. • One dose treatment is effective against round worm, pin worm and hook worm infections which are comparable to 3 days treatment with mebendazole. Three days treatment is necessary for tapeworms including H. nana. It has weak microfilaricidal action. • MOA is similar to mebendazole.
  15. 15. Albendazole • Clinical Uses: – Albendazole is administered on an empty stomach when used against intraluminal parasites but with a fatty meal when used against tissue parasites. – Ascariasis, trichuriasis, hookworm and pinworm infections: 400 mg oral/ adult and children older than 2 years of age (repeated for2-3 days for heavy ascaris infections and in 2 weeks for pinworm infection). – Hydatid disease: Adjunct to surgical removal or aspiration of cysts. 400 mg twice daily with meals for one month or longer. Daily therapy for up to 6 months has been well tolerated. – Neurocysticercosis: Corticosteroids are given with the anthelmintic drug to decrease inflammation caused by dying organisms. Albendazole is given in a dosage of 400 mg twice a day for up to 21 day. – Other infections: Treatment of cutaneous larva migrans (400 mg daily for 3 days); visceral larva migrans (400 mg twice daily for 5 days); microporidial infection (400 mg twice for 2 weeks or longer); gnathostomiasis (400 mg twice daily for 3 weeks).
  16. 16. Albendazole • Pharmacokinetics: – Albendazole is erratically absorbed after oral administration, but absorption is enhanced by a high-fat meal. – Its metabolized in liver and primarily excreted in urine. – t½ = approx. 8.5 hours. • Side effects: – When used for 1-3 days, albendazole is nearly free of significant adverse effects. – Mild and transient epigastric distress, diarrhea, headache, nausea, dizziness, lassitude, and insomnia can occur. – In long-term use for hydatid disease, albendazole is well tolerated, but it can cause abdominal distress, headaches, fever, fatigue, alopecia, increases in liver enzymes, and pancytopenia. – It has exhibited embryotoxicity in animals, use in pregnant women is contraindicated. It should be given with caution to patients with hepatic or renal disease.
  17. 17. Thiabendazole • Thiabendazole effective against threadworm, cutaneous larva migrans, and early stage of trichinosis. • PK: insoluble in water but readily available for oral absorption. It is hydroxylated in the liver and excreted in urine. • MOA: Same as mebendazole. Thiabendazole has antiinflammatory, analgesic and antipyretic actions. These may contribute to its effect in cutaneous larva migrans and other inflammatory conditions produced by larvae or worms in tissues. • ADR: Nausea, vomiting, loss of appetite, headache, giddiness are most common
  18. 18. Pyrantel pamoate • Pyrantel pamoate, along with mebendazole is effective in the treatment of infections caused by roundworms, pinworms and hookworms. • Pyrantel causes activation of nicotinic cholinergic receptors in the worms resulting in persistent depolarization, slowly developing contracture and spastic paralysis. • Its poorly absorbed orally and exerts its effects in the intestinal tract. • Adverse effects : Adverse effects are mild and include nausea, vomiting, and diarrhea.
  19. 19. Piperazine • Piperazine causes hyperpolarization of Ascaris muscle by GABA agonist action (opening of chloride channels  relaxation and decresses responsiveness to contractile action of Ach). • Orally active and partly metabolized in liver and excreted in urine. • ADR: Its safe and well tolerated. Dizziness and excitement occur at high doses. Toxic dose produce convulsion and death, due to respiratory failure. • Contraindicated in renal insufficiency and epileptics), but safe in pregnant.
  20. 20. Diethyl carbamazine citrate (DEC) • DEC developed in 1948, and its is the first drug for filariasis. • DEC absorbed after oral ingestion, well distributed, metabolized in liver and excreted in urine. Excretion is faster in acidic urine. Plasma t½ is around 4-12 hours.
  21. 21. Diethyl carbamazine citrate (DEC) • Diethylcarbamazine has a highly selective effect on microfilariae (Mf) at a dose of 2 mg/kg TDS. The most important action of DEC appears to be alteration of Mf membranes so that they are readily phagocytosed by tissue fixed monocytes, but not by circulating phagocytes. • Use: Used for the treatment of filariasis, tropical eosinophilia, Loa loa and O. vovulus infections. • ADR: ADR is common but not serious. Nausea, loss of appetite, headache, general weakness and dizziness.
  22. 22. Ivermectin • Is the drug of choice for the treatment of onchocerciasis (river blindness) caused by Onchocerca volvulus and for cutaneous larva migrans and strongyloidiasis. • Ivermectin targets the parasite’s glutamate-gated chloride channel receptors. Chloride influx is enhanced, and hyperpolarization occurs, resulting in paralysis of the worm. • The drug is given orally. It does not cross the blood-brain barrier and has no pharmacologic effects in the CNS. However, it is contraindicated in patients with meningitis, because their blood-brain barrier is more permeable, making CNS effects possible. • Dose: 10-15 mg oral dose with 400 mg of albendazole. Given annually for 5-6 years for filariasis.
  23. 23. Niclosamide • MOA: Inhibiting oxidative phosphorylation in mitochondria and interfering with anaerobic generation of ATP by the tapeworm. • ADR: Niclosamide is safe during pregnancy and in patients with poor health. It is well tolerated; minor abdominal symptoms are produced occasionally.
  24. 24. Drug for fascioliasis • Bithionol: – Used for the treatment of fascioliasis and cerebral paragonimiasis. – Bithionol is also an alternative drug in the treatment of pulmonary paragonimiasis. – Dose: 30-50 mg/kg – ADR: Mild and transient. Bithionol should be used with caution in children younger than 8 years.
  25. 25. Thank you
  26. 26. Echinococcus multilocularis Hydatid disease Back
  27. 27. Anthelmintic Drugs Roundworms Hookworm Pinworm Threadworm Whipworm
  28. 28. Anthelmintic Drugs Filaria Wuchereria bancrofti, Brugia malayi Guinea worm Dracunculus medinensis Tapeworms
  29. 29. Neurocysticercosis Back

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