Presented by:Samya Sayantan (121-29-381)Batch: 7th

Sec: ADepartment of PharmacyDaffodil International University

Presentation onAnthelmintic Drugs

Anthelmintics or antihelminthics are drugs that expel parasitic worms(helminths) from the body by either stunning or killing them.

They may also be called vermifuges (stunning) or vermicides (killing).

There has three major group of helminthes -the nematodes, trematodes and cestodes

Anthelmintic:

Mebendazole:Mebendazole is a synthetic benzimidazole

compound is effective against a wide spectrum of nematodes.

Mebendazole a medicine used to treat infections by worms.

This including pinworms, roundworms, tapeworms, hookworms, and whipworms.

Drugs for Nematodes

Binds with β-tubulin and inhibits microtubules polymerization.

Blocks glucose and other nutrients uptake.Resulting in the gradual immobilization

and eventual death of the helminthes.

Mechanism of action:

In heavy infestation casesDiarrhoeaNauseaAbdominal pain In high doseGranulocytopeniaAllergic reaction

Adverse Effect

Pyrantel pamoate along with mebendazole is effective in the treatment caused by roundworm, pinworm & hookworm.

It is poorly absorbed orally in the intestinal tract.

It is inactive against trichuris and other worms

Pyrantel pamoate:

Causes the release of acetylcholine and inhibits cholinesterase,

Acts as a depolarizing neuromuscular blocker,Paralyzing the helminthes,This has the result of causing the worm to

"lose its grip" on the intestinal wall and be passed out of the system by natural process.

Mechanism of action:

CNS: dizziness, headache, insomniaDermatologic: rashGIT: anorexia, nausea, abdominal cramps,

diarrheaNeuromuscular & skeletal: weakness

Adverse effect:

First benzamidazole polyanthelmintics.Chelating agents and form stable complexes

with metals including iron but does not bind with calcium.

Completely metabolized in liver.

Thiabendazole:

The precise mode of action of thiabendazole on the parasite is unknown, but it most likely inhibits the helminth-specific enzyme fumarate reductase.

Thereby inhibiting the citric acid cycle, mitochondrial respiration and subsequent production of ATP, ultimately leading to helminth's death.

Mechanism of action:

GI disturbanceIrreversible liver failureFatal Stevens-Johnson syndrome dizziness anorexia

Adverse effect:

Potent semisynthetic derivativeObtain from Streptomyces avermitilsDrugs of choice of strongyloidiasis,

filariasis, ascariasis, enterobiasis and some parasitic skin diseases including scabies

Ivermectin:

Acts on the parasites glutamate-gated Cl- channel receptors.

Chloride influx increased, hyper polarization occurs , resulting in paralysis of the worm.

Mechanism of action:

Fatigue, dizziness, GI disturbance

Nausea

Abdominal pain

Pruritis

Adverse effect:

Diethyl carbamazine is used as an anthelmintic drug in the treatment of filariasis because of its ability to immobilize microfilarae and render them susceptible to host defencse mechanism.

Diethyl carbamazine:

Immobilizes microfilariae and alters their

surface structure

displacing them from tissues & making them

susceptible to destruction by host defense

mechanism

It has immunosuppressive effects

Mechanism of action:

Fever, maliseheadache, GI disturbance, cough. Chest, muscle, joint pain

LeucocytosisRetinal hemorrhageIt is not teratogenic

Adverse Effect:

Praziquantel:Novel anthelmintic with wide range of action.Praziquantel is a drug which effective against

schistosomiasis and trematodes and cestodes.

Drugs for Tremadoes

Rapidly taken up by worms.Leakage of intracellular Ca++ causing

paralysis.Worms lose grip on intestinal wall including

tissues and veins.Acts against all stages of worm including

larvae.

Mechanism of action:

Bitter in tasteNauseaAbdominal painHeadacheDizziness and sedationRashes, fever, itching and body pain

Adverse Effect:

Niclosamide:Niclosamide is the drug of choice for most

cestode infections.It safe during pregnancy.

Drugs for Cestodes

Inhibition of oxidative phosphorylation in mitochondria

Interference of anaerobic generation of ATP by tapeworm.

Injured worms are digested or expelled (purgation)

Mechanism of action:

Well toleratedNo systemic toxicityMinor abdominal symptomsMalaise PruritisDiarrhea

Adverse Effect:

Congener of Mebendazole.One dose treatment has cure rate in

ascariasis, hookworm, enterobius.It is also used in the treatment of cestodal

infestations such as cysticercosis and hydatid disease.

Albendazole:

Binds with β-tubulin and inhibits microtubules polymerization.

Blocks glucose and other nutrients uptake.Intestinal parasites are immobilized and die

slowly.

Mechanism of action:

Well toleratedGI side effectsDizzinessProlonged used in hydatid and

cysticercosis- headache, fever, alopecia, neutropenia, jaundice.

Adverse Effect:

Pinworm disease:Causative agent: Enterobius vermicularisPruritus ani occurs with white worms visible in

stools or perianal regionTherapay: Mebedazole or Pyantel pamoate.

Common Nematodes Infections

Causative agent: Ascaris lumbricoidesIngested larvae grow in the intestineCausing abdominal symptoms including

intestinal obstractionRoundworms may pass to blood and infect

the lungs.Therapy: Pyrantel pamoate or Mebendazole

Roundworm disease:

Causative agents: Trichinella spiralisUsually caused by consumption of

insufficiently cooked meat, especially porkTherapy: Thiabendazole (only in the early

stages of disease

Trichinosis disease:

Causative agents: Ancylostoma duodenale (old world), Necator americanus (new world)

Worm attaches to the intestinal mucosa, causing anorexia and chronic intestinal blood loss that leads to anemia.

Therapy: Pyrantel pamoate or Mebendazole

Hookworm disease:

Paragonimiasis: Causative agent: Paragonimus westermani

(lung fluke). The organisms move from the GI tract to

the lung which is the primary site of damage

Paragonimiasis is transmitted by eating raw crab

Diagnosed by identifying eggs in the sputum & stool.

Therapy: Praziquantel

Common Trematodes Infections

Causative agent: Clonorchis sinensis (oriental liver fluke)

The primary site of infection is the biliary tract where the resulting inflamatory response can cause fibrosis & hyperplasia

Transmitted by eating raw freshwater fish.Diagnosed by indentifying eggs in the stoolTherapy: Praziquantel

Clonorchiasis:

Echinococcosis:Causative agent: Echinococcus granulosusInfection produces large hydatid cysts in the

liver, lung and brain.Sheep often serve as an intermediate.Diagnosed by CT scan or biopsy of infected

tissue and is treated by surgical excision of cysts.

Therapy: Albendazole

Common Cestodes Infections

Causative agent: Taenia solium larvae Infection produces cysticerci in brain and

eyes.Cysticercosis is diagnosed by CT scan or

biopsy.Therapy: Praziquantel, Albendazole or

Surgery

Cysticercosis: