ANTHELMINTIC DRUGS ( antihelmintics)

You should be able to choose drugs of choice for common infection of nematodes, trematodes and cestode

Describe the mechanism of action and major toxic effect of the anthelmintic drugs

Learning Objective

Albendazole Mebendazole ( visceral larval migrans) Thiabendazole Praziquantel Diethylcarbamazine citrate Ivermectin ( cotaneous larva migrans,

filariasis)

Drugs for Tissue Infections & Intestinal Infections

Niclosamide Piperazine citrate Pyrantel pamoat

Intestinal Infections

1. Albendazole2. Diethylcarbamazine3. Ivermectin4. Benzimidazoles5. Pyrantel pamoate6. Piperazine

DRUGS THAT ACT AGAINT NEMATODE

Mechanism unknown Clinical use

◦ Filariasis (DOC)◦ Alternative for onchocerciasis

Toxicity: fever,rashes,ocular damage, joint and muscle pain,lymphangitis.

Diethylcarbamazine

Mechanisms: intensifies GABA-mediated neurotransmission in nematodes

Clinical use: Active on most common intestinal worms (except tapeworms), most mites, and some lice. Strongyloides stercoralis, onchocerciasis (DOC). And alternative agent in filariasis

Toxicity: fever, headache, dizziness, rashes, pruritus, tachycardia, hypotensi, pain in joints, muscle and lymph glands (Mazzotti reactions)

Ivermectin

Albendazole, mebendazole, thiabendazole Inhibit glucose absorption and inbiting

microtubule synthesis Poorly absorbed (PO). Active against nematodes (drugs of choice). Toxicity: gastrointestinal irritation, allergic

reaction, embryotoxicity

Benzimidazoles

Mechanisms: stimulate nicotinic receptor present at Neuromuscular junction of nematodes. Contraction of muscle occurs depolarization-induced paralysis

Clinical use: drugs of choice for infection due ti hookworm, pinworm and roundworm

Tocixity: Nausea, vomiting, deadache, weaknes and neurotoxic effects ...

Pyrantel pamoate

1. Praziquantel2. Bithionol3. Metrifonate4. Oxamniquine

DRUGS THAT ACT AGAINST TREMATODES

1. Niclosamide2. Praziquantel3. Albendazole4. Mebendazole

DRUGS THAT ACT AGAINST CESTODES

Mechanism: increases membrane permeaility to calcium

Clinical use: trematodes and cestodes.

Drugs of choice in schistomiasis, clonorchiasis, paragonimiasis and in the treatment of cysticercosis

Toxicity: Headache,dizziness,malaese, fever, skin rash and G I Tract iritation. Contraindicated in ocular cysticercosis.

PRAZIQUANTEL

Bithionol

Mechanism : unknownClinical use: The drugs of choice for treatment of fascioliasis and an alternative drugs in paragonimiasis

Toxicity: nausea, vomiting, diarrhea, abdominal cremps, headache,dizziness,malaese

Mechanism: unccoupling oxidative phosphorilasi or by activating ATPase

Clinical : tapeworm infection not for cysticercosis. Active against T. saginata, D. latum, H. Nana, D. caninum, T. solium (risk of autoinfection due to disintegration; prefer praziquantel).

Toxicity: headache, GI tract. Fever rash by antigen of parasite.

NICLOSAMIDE

SUMMARY

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Iverm ec tinM eb en d azo le

D ru g s ac tiveag a in s t

N em atod es

P raz iq u an te lB ith ion o l

M etrifon a teO xam n iq u in e

D ru g s ac tiveag a in s t

Trem atod es

N ic losam id eP raz iq u an te lA lb en d azo le

M eb en d azo le

D ru g s ac tiveag a in s t

C es tod es

A n th e lm in tic D ru g s