Antihelmintic%20drugs

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• Antihelmintic drugs
• By
• Dr.Mohamed Abd AlMoneim Attia

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Antihelmintic drugs
Drugs active against cestodes
Drugs active against nematodes
Drugs active against trematodes
Niclosamide Praziquantel Albendazole mebendazole

• Diethylcarbamazine (systemic)
• Albendazole
• Mebendazole
• Pyrantel pamoate
• Ivermectin

Praziquantel Metrifonate oxamnquine
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Drugs active against nematodes

• Intestinal nematodes includes
• 1-enterobius vermicularis (pinworm)
• 2-ascaris lumbricoides (roundworm)
• 3-ancyclostoma necator species (hookworm)
• 4-strongyloides stercoralis (threadworm)
• Tissue nematodes onchocerca,filariasis

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pinworm
hookworm
Round worm
threadworm
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Albendazole

• Mechanism of action
• block glucose uptake by the parasite leading to
  decrease production of energy and subsequent
  parasite immobilization
• Uses
• 1-treatment of roundworm,pinworm,hookworm
  infection
• 2-alternative treatment of threadworm,filariasis
• 3-hydatid disease cysticercosis

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• Side effects
• 1- short course treatment has few side effects
• 2-long course treatments leucopenia, alopecia
  elevation of liver enzymes

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Diethylcarbamazine

• Mechanism of action
• Immobilizes microfilaria by unknown mechanism
  increase host susceptibility to attack it.
• Uses
• Drug of choice in filarial
• infection of the eye (loa loa)
• Alternate drug in elephantiasis.

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• Side effects
• 1-headache,malasie,weakness,nausea
• 2-reaction to dying filaria includes fever,
  rash,ocular damage, joint pain and lymphangitis

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Ivermectin

• Mechanism of action facilitates GABA mediated
  neurotransmission in nematodes causing
  immobilization of the parasite, facilitating its
  removal by reticuloendothelial system.
• Uses
• Drug of choice in treatment of onchocercosis, and
  threadworm infection

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• Side effects
• Mazzotti reactions(due to killing of
  microfilaria) and includes,fever, joint pain,
  rash hypotension,tachycardia

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Mebendazole

• Mechanism of action
• Inhibit glucose uptake and microtubule synthesis
  in nematodes.
• Uses
• Primary drug in roundworm and pinworm infection
• Side effects
• GIT upsets, alopecia and agranulocytosis in high
  dose

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Piperazine

• Mechanism of action
• Act as GABA receptor agonist causing paralysis of
  the parasite and expelled live by normal
  intestinal peristalsis
• Uses alternate drug in treatment of roundworm
  infection.
• Side effects GIT upsets, teratogenic

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Pyrantel pamoate

• Mechanism of action
• Stimulate nicotinic receptor present at the NMJ
  of nematode.contraction of the muscle occurs
  followed by depolarization induced paralysis.
• Uses
• 1- drug of choice for hookworm roundworm
  infection
• 2-alternate drug in pinworm infection
• Side effects mild GIT upsets

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Thiabendazole

• Mechanism of action like mebendazole
• Uses alternate drug in threadworm infection
• Side effects unsafe drug
• 1-GIT irritation,headache,drowsiness
• 2-leukopenia,haematuria
• 3-allergic reaction

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Drugs active against trematodes

• Medically important trematodes are
• 1-schistosoma species (blood fluke)
• 2-clonorchis sinesis (liver flukes in southeast
  Asia)
• 3-paragonimus westermani ( lung fluke in
  Asia,India)

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Praziquantel

• Mechanism of action
• Increase membrane permeability to calcium causing
  muscle contraction followed by paralysis leading
  to vacuolization and death of the parasite.
• Uses
• 1- drug of choice of all trematodes infection
• 2-one of 2 drugs of choice in cestodes infection

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• Side effects
• 1-common adverse effects GIT upset,headach,malais
  e,skin rash
• 2-intracranial hypertension and convulsion if
  used in ttt of neurocysticercosis
• Contraindication ocularcysticercosis

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Bithionol

• Uses
• Drug of choice in ttt of fascioliasis ( sheep
  liver fluke)
• Side effects
• 1-common N/V,headache,phototoxcity
• 2-less common protenuria,leucopenia

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Drugs active against cestodes

• The 4 important cestodes are
• 1-taenia saginata ( beef tapeworm)
• 2-taenia solium ( pork tapeworm that causes
  cysticerci in brain and eye)
• 3-diphyllobothrium latum ( fish tapeworm)
• 4-echinococcus granulosus (dog tapeworm that
  cause hydatid cysts in lung,liver,and brain)

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beef tapeworm
Hydatid cyst in liver
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Niclosamide

• Mechanism of action
• Act by activating ATPases
• Uses
• 1- 1 of 2 drugs of choice ( with praziquantel) in
  ttt of fish,pork,and beef tapeworms infection
• 2-not effective in cycticercosis (albendazole or
  praziquantel is used)
• 3- not effective in hydatid disease ( albendazole
  is used).
• Side effects
• Mild GIT upset, rash headache

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Drug for treatment of nematodes
Infecting organism Drug of choice Alternative drug
Ascaris(roundworm) Albendazole,mebendazole,pyrantel pamoate piperazine
Ancylostoma(hookworm) Albendazole,mebendazole, pyrantel pamoate
Strongyloids stercoralis(threadworm ivermectin Albendazole,mebendazole,
Enterobius vermicularis(pinworm) Mebendazole,pyrantel pamoate albendazole
filariasis diethylcarbamazine ivermectin
onchocericasis ivermectin --------


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Drug for treatment of trematodes
Infecting organism Drug of choice Alternative drug
s,.haematobium praziquantel metrifonate
s.mansoni praziquantel oxamniquine
s.japonicum praziquantel
Fasciola hepatica bithional
Fasciolopsis buski Praziquantel or niclosamide
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Drug for treatment of cestodes
Infecting organism Drug of choice Alternative drug
t.Saginata (beef tapeworm) Praziquantel or niclosamide mebendazole
t.Solium(pork tapeworm) Praziquantel or niclosamide
Cysticercosis(pork tapeworm larval stage) albendazole praziquantel
Diphyllobothrium latium(fish tapeworm) Praziquantel or niclosamide
Hydatid disease albendazole
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Drugs for leishmaniasis

• Sodium stibogluconate for all types of
  leishmania ( must be given by injection and
  cardiotoxic)
• Alternate drugs
• 1-Pentamidine for visceral leishmaniasis
• 2-Fluconazole or metronidazole for cutaneous
  lesions
• 3-Amphotricin B for mucocutaneous lesions

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ANTIHELMINTHIC DRUGSTherapeutic Strategies

• Inhibit muscle contraction
• Inhibit energy metabolism
• Limit distribution of generally toxic drugs

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• Thank you