Antihelmintic drugsBy
Dr.Mohamed Abd AlMoneim Attia
Antihelmintic drugs
Drugs active against nematodes
Drugs active against trematodes
Drugs active against cestodes
Diethylcarbamazine (systemic)
Albendazole
Mebendazole
Pyrantel pamoate
Ivermectin
Praziquantel
Metrifonate
oxamnquine
Niclosamide
Praziquantel
Albendazole
mebendazole
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
Round wormthreadworm
hookwormpinworm
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
Side effects:
1- short course treatment :has few side effects
2-long course treatments: leucopenia, alopecia & elevation of liver enzymes
Diethylcarbamazine
Mechanism of action:
Immobilizes microfilaria by unknown mechanism increase host susceptibility to attack it.
Uses:
1. Drug of choice in filarial
infection of the eye (loa loa)
1. Alternate drug in elephantiasis.
Side effects:
1-headache,malasie,weakness,nausea
2-reaction to dying filaria includes: fever, rash,ocular damage, joint pain and lymphangitis
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
Side effects:
Mazzotti reactions(due to killing of microfilaria) and includes,fever, joint pain, rash hypotension,tachycardia
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
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
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
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
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)
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
Side effects:
1-common adverse effects: GIT upset,headach,malaise,skin rash
2-intracranial hypertension and convulsion if used in ttt of neurocysticercosis
Contraindication: ocularcysticercosis
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
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)
beef tapeworm
Hydatid cyst in liver
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 infection2-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
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 --------
Drug for treatment of nematodes
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
Drug for treatment of trematodes
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
Drug for treatment of cestodes
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
ANTIHELMINTHIC DRUGSTherapeutic Strategies
Inhibit muscle contraction Inhibit energy metabolism Limit distribution of generally toxic drugs
Thank you
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