7 anthelmintic drugs


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7 anthelmintic drugs

  1. 1. ANTIHELMINTICDRUGS Indupalli Avinash & Paruchuri Aswini chand 1
  2. 2. INTRODUCTION Humans are the primary hosts for the most of helminthic infections. Most worms produce in human sexually by producing eggs and larvae These pass out of body and infect the secondary host Imature forms invade humans via skin or GIT and mature to adult worms with characteristic tissue distribution. 2
  3. 3. Types (clinical)1. Worms live in hosts alimentary canal.2. Worms or larvae live in other tissues of host body like muscles , viscera , meninges , lungs, subcutaneous tissues. 3
  4. 4. INTESTINAL WORMS CON’DA) INTESTINAL ROUND WORMS (NEMATODES) Ascaris lmubricods (common round worm) Enterobius vermicularis (pin worm) Trichuris trichuria ( whip worm) Strongyloids stercoralis ( thread worm) Ankylostoma dudenale (hook worm) 4
  5. 5. Ascaris lumbricoids ( common round worm) 5
  6. 6. Hookworm 6
  7. 7. Pinworm male ,female 7
  8. 8. whipworm 8
  9. 9. Tricuris tricura(whip worm) 9
  10. 10. 1. Alimentary canal(intestinal tape worms) B)TAPE WORMS (CESTODES)  Taenia saginata(Beaf) ,  Taenia solium(Pork),Hymenolepis nana(Dwarf) ,diphylobothrium latum(Fish)  Humans become infected by eating raw or under cooked meat containing larvae of infected cattle or pig which has encysted in the animal muscle tissue. 10
  11. 11. Cestodes con’d In some conditions this larvae may develop in humans resulting cysticercosis (i.e. larvae gets encysted in the muscle and viscera or more seriously in the brain or eye.) In case of H.nana both adult worm and larvae can be present in the same host. In case of D.latum infections occurs by eating raw 11 or undercooked fish
  12. 12. Tapeworm 12
  13. 13. cysticercosis 13
  14. 14. 2. TISSUE WORMSA.TREMATODES(Schisotomes)ORFLUKES(leaf like) Schistosoma haematobium Schistosoma Japonicum Schistosoma mansoni (These cause SCHISTASOMIASIS) also called (BILHARZIA) means disease of blood vessels. Adult worms of both sex live and mate in veins or venules of the gut wall or the bladder, eggs pass into the bladder or gut and produce inflammation of these organs , resulting in haematuria or loss of blood in feces. 14
  15. 15. Tremtodes (flukes) con’d Eggs hatch in water and develop in to miracidia(1st stage of larva of trematode and further develop in the body of snail), which enter to 2ndry host a particular species of snail ,where it develops to free swimming cercarae (final free-swimming stage of a trematode),These infect humans by penetrating to skin 15
  16. 16.  Paragonimus westermani (lung fluke) disease is caused by eating raw crab or fish , larvae move from intestine to blood and settle in lungs Clonorchis sinensis(liver fluke) disease is caused by eating raw fish and worm settle in the biliary tract 16
  17. 17. Tissue worms cont’d B. TISSUE ROUND WORMS Trichnella spiralis. Dracunulus medinensis (guinea worm)larva migrate from intestine to tissue of leg or foot and protrude out by making ulcer 17
  18. 18. FILARIAE includes Wuchereria bancrofti Loa loa Onchocerera volvulus Brugia malayi 18
  19. 19. Trichinela spiralis 19
  20. 20. filariasis 20
  21. 21. Wuchereria or Brugia obstructs lymphatic vessels producingelephantiasis elephantiasis 21
  22. 22. Filariae: Wucheria bancrofti ,loa loa , onchoceravolvulus and Brugia malayi Adult filariae live in the lymphatics,and cause lymphadenitis and swelling of limb. connective tissue or mesentery of host and produce live embryos or microfilariae, which goes to blood stream. They are ingested by mosquitoes or similar insects, they develop to larvae in 2ndry host and pass to mouth parts of insect and 22 re-injected to humans
  23. 23. C. Hydatid tape worm Echinococcus species . These are cestodes ,primary in canines (dogs) and sheep as intermediate host. humans can act intermediate host in which larvae develop to hydatid cyst with in tissue. 23
  24. 24. Hydateid cyct 24
  25. 25. Helminths commonly infecting manNematodes( round worm)Tissue worms wuchereria bancrofti Filariasis Brugia malayi Filariasis Loa loa loiasis Onchocerca River blindness Dracunculus medinensis DracunculiaissIntestinal human nematodes Enterobius vermicularis Threadworm Ascaris lumbricoides Roundworm Trichuris trichiura Whipworm Nector americanus Hookworm Ancylostoma duodenale Hookworm Strongyloides stercoralis Strongyloidosis Trematodes(flukes)Blood flukes Schistosoma species SchistosomiasisLung flukes Paragonimus speies ParagonimiasisIntestinal / hepatic flukes Fasciolopsis buski Fasciola hepatica Clonorchis sinensis 25
  26. 26. Helminths commonly infecting man cont’dCestodes(tapeworms)Intestinal adult worms Taenia saginata Beef tapeworm Taenia solium Porktaperworm Diphyllobothrium latum Fishetapeworm Hymenolepis nana DwarftapewormLarval tissue cysts Taenia solium cysticercosis Echinococcus granulosus Hydatid disease Echinococcus multilocularis Hydatid disease Spirometra mansoni Sparganosis 26
  27. 27. Diseases caused by filarial wormsOrganism adult worm Microfilariae C.signsW. bancrofti Lymphatics Blood Fever lymphangitis ElephantiasisB.Malayi lymphatics Blood Fever lymphangitis ElephantiasisLoa loa Subcutaneous Blood UrticariaOnchocerca Subcutaneous skin,eye subcut nodules Eye diseaseMansonella perstans Retroperitoneal Blood Allergic eosinophilia 27
  28. 28. Dircrocoelium dendriticum 28
  29. 29. Fasiola hepatica 29
  30. 30. ANTHELMINTIC DRUGS BENZIMIDAZOLES 1.ALBENDAZOLE: It is a broad spectrum It is a drug of choice (primary therapeutic application) for treatment of hydatid disease and cystecercosis, it is also used for the treatment of (intestinal nematodes) pinworm, hookworm 30
  31. 31. Albendazole con;d Mechanism of action: It inhibits microtubule synthesis in nematodes(intestinal round worms) that irreversibly impairs glucose uptake, intestinal parasites are immobilized and die slowly. 31
  32. 32. Pharmacokinetics (Albendazole) It is benzimidazole carbamate it is adminstered orally , and absorbed erratically (unpredictable) , absorption can be increased with fatty meal It is metabolized in the liver rapidly to active metabolite albendazole sulphoxide 32
  33. 33. Pharmacokinetics (Albendazole) It has a plasma half life of 8-12 hours Sulphoxide is mostly protein bound , distributes well to tissues and enters bile, csf. Metabolites are excreted in urine 33
  34. 34. Clinical uses (albendazole) used on empty stomach when used against intraluminal parasites but with fatty meal when against tissue parasites. In hookworm, pin worm infection : children under 2 years 400 mg orally as a single dose repeated after 2-3 wks for pin worm2. Hydated diseases: drug of choice ,400 mg twice with meals for 1 month or longer. 34
  35. 35. Albendazole con’d3. Neurocysticercosis: It is controversial as it has not proved superior to corticosteroid alone. It is used along with cotricosteroid to decrease the inflammation caused by dying organism and it also reduces the duration of course i.e. 400 mg twice daily for 21 days 35
  36. 36. Albendazole con’d Adverse effects: In short term: use no significant adverse effects. In long term use : as used in abdominal distress, headache ,fever , fatigue, alopecia , increased liver enzymes , pancytopenia. Blood counts and LFT should be followed. Not given during pregnancy and in hypersensitive people. 36
  37. 37. MEBENDAZOLE(Vermox) it is a synthetic benzimidazole it has wider spectrum and is more safer than albendazoleMechanism of action:It inhibits microtubule synthesis in nematodes that irreversibly impairs glucose uptake.Intestinal parasites are immobilized and die slowy. It kills hook worm, pin worm , ascariasis and trichuris eggs. 37
  38. 38. Mebendazole con’tPharmacokinetics: less than 10% of orally administered drug is absorbed Absorption increases with fatty meal. Absorbed drug is 90 % protein bound It is converted to inactive metabolites rapidly in liver. It has half life of 2-6 hours It is primarily excreted in urine. 38
  39. 39. Mebendazole con’tClinical uses: It is taken orally before or after meal tablets should be chewed before swallowing. Pinworm infection: 100 mg as a single dose, to be repeated after 2-3 weeks. in adults and children over 2 years cure rate is 90-100 % except hook worm but there occurs marked reduction 39
  40. 40. Mebendazole con’d Intestinal cappilliaris: 400 mg /day in divided doses for 21 day or more. Trichinosis :it has limited efficacy against adult worm.200-300 mg for 3 days ,then 400-500 mg for 10 days with fatty meal and co-administration with corticosteroids in sever infection 40
  41. 41. Mebendazole con’d Adverse effects and precautions: No adverse effects in short term therapy.Mild GI disturbance. With high dose Hypersensitivity reactions,agranulocytosis , alopecia ,elevation of liver enzymes . used with caution under 2ys of age may cause convulsion in this group. enzyme inducers and inhibitors affect plasma level of the drug. hepatic parenchymal disease 41
  42. 42. Thiabendazole it is benzimidazole it is chelating agent and form stable complexes with metals including iron, but does not bind with calcium. it is rapidly absorbed it has half life of 1.2 hrs It is completely metabolized in liver and 90% is excreted in urine it can also get absorbed through skin 42
  43. 43. Thiabendazole con’d: mechanism of action: similar to other benzimidazoles.It is ovicidal for some paracites clinical uses: should be given after meals .and tablets should be chewed for thread worms infections: 25 mg /kg ( not more than 1.5 grams) twice daily for 2 days ,can be repeated after 2 week. In hyper infection syndrome drug is continued twice daily for 5-7 days. 43
  44. 44. Thiabendazole con’d adverse reactions and contraindications: It is more toxic than other benzamidazoles GI disturbances Pruritus ,headache, drowsiness , psychoneurotic symptoms. Irreversible liver failure. Fatal Steven –Johnson syndrome(inflammation of skin) Not used in children below 15 kg weight. pregnancy, hepatic and renal diseases. 44
  45. 45. PYRANTEL PAMOATE It is a broad specturm anthelmintic but it is not effective against tricuriasis(whip worms), and trichostrongylus orientalis infections. Oxalate pamoate is effective Pharmacokinetics: It is poorly absorbed orally , Half of the drug is excreted unchanged in the feces. Mechanism of action: It is a depolrazing neuromuscular blocking agent that causes release of acetylcholine and inhibition of cholinestrase leads to paralizes of worms. 45
  46. 46. Pyrantel pamoate con’dEfficacy and clinical uses: it is very effective against luminal organisms. It is not effective against migratory stages in the tissues or against ova pin worm: 11 mg /kg as a single dose to be repeated in 2 wks. common round worm: single dose to be repeated after 2wks hook worm: single dose for light infection but a 3 days course is necessary for heavy infection.especially N amerianus. 46
  47. 47. Pyrental pamoate con’d Adverse Effects . Infrequent mild transient GI disturbance drowsiness , headache ,insomnia. Rash ,feverContraindciations Should not be used in liver diseases. Pregnancy and child under 2 years of age 47
  48. 48. PIPERAZINE Only recommended for the treatment of ascariasis. it is absorbed orally and excreted in urine Mechanism of action: it causes paralysis of ascaris by blocking acetylcholine at myoneural junction ,expelling the live worm by normal peristalsis.Not recommended for other helminth infections 48
  49. 49. Piperazine con’d pharmacokinetics : it is readily absorbed orally and excreted unchanged in urine. 75 mg /kg/day for 2 days once daily treatment is continued for 3-4 days or repeated after one week in case of heavy infections. 49
  50. 50. Piperazine con’d Adverse effects: GI disturbance Neurotoxicity ,allergic reactions serum sickness like syndrome Contraindications Epilepsy Impaired liver or kidney functions pregnancy Malnutrition 50
  51. 51. NICLOSAMIDE It is a useful drug for treatment of tape worm (cestodes)infestation Mechanism of action: Adult worm is rapidly killed by inhibition of oxidative phosphorylation or stimulation of ATPase activity. Pharmacokinetics: It is poorly absorbed from gut Neither drug nor its metabolites are found in blood or urine 51
  52. 52. Niclosamide con’d Clinical uses: Beef tape worm, pork tape worm, fish tape worm. 2 gram of single dose is given in the morning on the empty stomach. not effective against cysticercosis or hydatic disease. Hymenolepis nana: It is effective against adult parasite 52
  53. 53. Niclosamide con’d Adverse effects: Mild ,infrequent and transitory GI disturbance Alcohol consumption should be avoided not indicated in children under 2 years of age. 53
  54. 54. DIETHYLCARBAMAZINE Is a drug of choice for the treatment of filariasis and tropical eosinophillia. Pharmacokinetics: It is synthetic peprazine derivative Rapidly absorbed from gut It has a half life of 2-3 hours which increases in alkaline urine to 10 hours. It is excreted in urine unchanged. dosage is reduced in urinary alkalosis and renal impairment. 54
  55. 55. DIETHYLCARBAMAZINE con’d Mechanism of action: It immobilizes microfilariae and alters its surface structure ,making them susceptible to destruction by host defense mechanis It is not teratogenic 55
  56. 56. DIETHYLCARBAMAZINE con’d It is a drug of choice for the treatment of W.bancrofti, B.malayi,B.timori, loa loa Microfiliariae are rapidly killed .adult worms are killed slowly requiring several course of treatment It is highly effective against L.loa. for these infections the dose is 2mg/kg three times a day for 2-3 weeks. for W.bancrofti infections to reduce the incidence of allergic reactions to dying microfilariae a single dose is administered on the first day , two doses on the second day and three doses on the 3rd day. 56
  57. 57. DIETHYLCARBAMAZINE con’d For loa ( with risk of encephalopathy) or B.malayi infections ,individual doses should start at 1 mg /kg once on the first day and gradually increased over 5-6 days Anti histamines and corticosteroids are given in allergic manifestations. Complete Cure may be require several courses of treatment over 1-2 years. The drug may be used in prohylaxis 300 mg weekly or 300 mg on 3 successive day each month for 57 loiasis.
  58. 58. DIETHYLCARBAMAZINE con’d Reactions induced by Dying parasites: Fever , mailase, papular rash, headache, GI disturbance,cough, chest,muscle,joint pain Leucocytosis Retinal haemorrhage Encephalopathy lymphangitis and lymphadenopathy. 58
  59. 59. DIETHYLCARBAMAZINE con’d contraindications and precautions Hypertension Renal disease Patient suspected of malaria patient with lymphangitis 59
  60. 60. IVERMECTIN It is drug of choice for treatment of filaria and onchoceriais,elephantiasis it is a macrocyclic lactone It is used orally and is rapidly absorbed, posses wide volume of distribution. It has a half life of 16 hrs It is exclusively excreted in urine 60
  61. 61. IVERMECTIN con’d Mechanism of action:61 it intensifies GABA –mediated transmission of singals in peripheral neverse In onchoceriasis it is microfilaricidal It does not kill adult worm 61
  62. 62. IVERMECTIN con’d Clinical uses: Onchoceriasis: a single dose of 150 mg/kg with water on empty stomach,repeated after every 3 months for one year,after this it is repeated yearly untill adult worm dies which may take a year or more 62
  63. 63. IVERMECTIN con’d Strongyloidiasis: 200mg for 2 days in immunosuppresed patient ,repeated treatment is often needed. Bancrofti filaricidal: as it is mirofilaricidal It is also used for scabies and cutaneous larva migrains. 63
  64. 64. IVERMECTIN con’d Adverse effects: Fatigue ,dizziness, GI disturbance In onchoceriasis: Mazotti reaction i.e. fever, headache, dizziness, somonlence, weekness, rash ,diarrhea, arthralagia, hypotension, lymphadenitis, peripheral edema due to killing of microfiliariae, for this steroids may be necessary for several days Swelling and abscess at site of adult worm Punctuate corneal opacities. 64
  65. 65. IVERMECTIN con’d Contraindication: other drugs that enhance GABAe.g Barbiturates, bnezodiazepines, valproaic acid. pregnancy Imparied blood brain barrier Children under 5 years of age. 65
  66. 66. BITHIONOL it is drug of choice for the treatment of fasioliasis ( sheep liver fluke) It is also alternative drug for pulmonary paragonimiasis Pharmacokinetics: It is orally administered and excreted in urine. 66
  67. 67. BITHIONOL Clinical uses: 30-50 mg /kg in 2-3 divided doses administered orally after meals on alternate day for 10 – 15 days. Adverse effects: GI disturbance Dizziness,headache Pruriuts ,urticaria,Leucopenia Contraindications and precautions: hepatitis ,leucopenia Used with caution under 8 years of age. 67
  68. 68. 68