Anthelminthic drugs are used to treat helminthic parasite infections. The main types of helminths that infect humans are nematodes (roundworms and hookworms), trematodes (flukes), and cestodes (tapeworms). Common anthelminthic drugs include mebendazole, albendazole, pyrantel pamoate, praziquantel, ivermectin, diethylcarbamazine, niclosamide, and piperazine. These drugs work by paralyzing or killing the parasites and helping expel them from the intestinal tract or tissues. The ideal anthelminthic is broad spectrum, achieves high cure rates with

1. Anthelminthic Drugs

2. • Anthelmintics:-
• Drug use to eradicate or reduce the numbers of helminthic parasites in the
intestinal tract or tissues of the body
• 3 major groups of helminths infecting humans
1. Nematodes (Round: hook, whip, thread, Pin, Filaria, guinea worms)
• Round worm-Ascaris lumbricoides
• Hook worm- Ancylostoma duodenale
• Whipworm- Trichuris trichiura
• Pinworm- Enterobius vermicularis
• Symptoms: nausea, abdominal pain and cough.
• Live worms are passed through stool or vomit.
• Transmission→ through the fecal – oral route, or by fingers contaminated by soil
seeded with the eggs of the round worm.

3. 2. Trematodes or Flat worms (Flukes: blood, lungs, GIT )
 Blood Flukes- schistosomia haematobium
 Biliary Flukes (Hepatic)-Clonorchis sinensis
 Intestinal Flukes
 Lung Flukes- Paragonimus westermani
• 3. Cestodes (Tape: beef, pork, fish, dwarf worm)
• Cestodes have a flat, segmented body and they attach to the host’s intestine.
• lack a mouth & digestive tract
• Infestation by tapeworms or cestodes is transmitted by ingestion of infected beef
or pork.
• Tenia solium-Pork tapeworm

4. • Tenia saginata- beef tapeworm
• Diphyllobothrium latum-Fish tapeworm
• So proper cooking required
• Vermicides→ Drug that kill worms
• Vermifuges→ Drug that expel the worms
• They are of huge importance for human tropical medicine & veterinary medicine
• Ideal anthelmintic drugs:-
• Broad spectrum of action
• Achieve a high percentage of cure with a single dose.
• Not get absorbed
• Free from toxic effects
• Palatable and cheap

5. ANTHELMINTIC DRUGS
For
Round worm,
Hookworm,
Pin worm
Albendazole
Mebendazole
Pyrantel
Pamoate
Piperazine
Levamisole
For
Threadworm
Ivermectin
Albendazole
For Whipworm,
Trichinella spiralis
Albendazole
Mebendazole
For Filariasis
 Diethylcarbamazine
 Ivermectin
 Albendazole
 Praziquantel
 Niclosamide
 Albendazole
For Tapeworms
 Albendazole
 Mebendazole
For Hydatid Disease

6. Drugs includes:-
•Mebendazole
•Albendazole
•Niclosamide
•Ivermectin
•Pyrantel pamoate
•Levamisole
•Praziquantel
•Piperazine
•Diethylcarbamazine citrate(DEC)

7. Mebendazole:-
• A broad spectrum Anthelmintic
• It is poorly absorbed when given orally
• MOA:-It acts by binding to β-tubulin and interfering with the synthesis of the
parasite’s microtubules
• Also inhibit glucose transport into the parasite
• Result→ intestinal parasites are immobilized/die slowly
• Affected parasites are expelled with faces.
• It is relatively free of toxic effects.
• Pharmacokinetics:-
• Absorption-poorly absorbed from GI tract
• Distribution-highly bound to plasma protein
• Metabolism-liver

8. • Excretion-faeces
• A/E:- Anorexia, nausea, vomiting, fever,
• Contraindication:- Pregnancy, because of its Embryotoxic and Teratogenic
effects.
• Below 1year
• USES:- DOC for intestinal nematodes-round worm, hookworm, whipworm, pin
worm
• Dose:-100mg BD for 3 days
• Albendazole:-
• It is effective against many common intestinal worms in a single dose.
• The drug is well tolerated
• Mechanism of action similar to Mebendazole
• Broad spectrum anthelmintic activity
• Pharmacokinetics:-Fatty food→↑absorption

9. • Produce metabolic product → Albendazole sulphoxide
Hydatid cyst hence preferred in the treatment of hydatid disease
• A/E:-Rare Adverse effect (well tolerated) Nausea, vomiting
• USES:-
• Nematodes- Round worm(Ascaris l) ,hook worm (Ancylostoma D)
• Neurocysticercosis-DOC
• Advantages:-
Cheaper
Duration of treatment is shorter
Reaches high concentration in brain& CSF
Less toxic & better tolerated
• Hydatid disease
• Filariasis-as a adjuvant 400mg with DEC
Widely distributed

10. -:Levamisole:-
• Effective against round-worm & hookworm infestations (Ascaris &
Ancylostoma )
• MOA:-Drug causing spastic paralysis in worms by acting as Agonist on Nn
receptor (stimulation of ganglia)
• Also inhibit carbohydrate metabolism in parasitic worms
• Immunomodulator-↑T-cell number in Hodgkin disease
• In Colorectal cancer:- 5-FU+levamisole
• Adult dose-150mg
• A/E:-headache, dizziness, insomnia, Nausea
-:Niclosamide:-
• Vermicidal drug for all varieties of Taeniasis.
• MOA:- Inhibits oxidative Phosphorylation in the mitochondria of the parasite
• Poorly absorbed from GIT
• Given orally in the form of chewable tablets

11. -:Ivermectin:-
Ivermectin is a Macrocyclic lactone(16 membrane lactones ).
MOA:-
Ivermectin
Binds to glutamate-activated Cl- channels found in
nematode nerve or muscle cells
↑intracellular cl- concentration
causes hyperpolarization by,
resulting in paralysis

12. Pharmacokinetic:-
Absorption:-Well orally
T1/2-57hr.
PPB-high (90%)
Metabolism:-Liver (CYP3A4)
USES:-
Onchocerciasis- DOC
Cutaneous larva migrans:- DOC
Filariasis:-200mg ivermectin + Albendazole400mg
Lymphatic filariasis:-Ivermectin 400mg+ DEC 6mg/kg as single oral dose
every 6-12 month(regimens)
A/E:- Itching, rashes, headache, fever

13. Praziquantel:-
• Effective-Trematodes (Flukes) & Tapeworms & Not effective → Nematodes
• MOA:- Causes Ca2+ influx and spastic paralysis of adult worms
• Absorption:- well orally→↑ with Food (80% BA)
• First pass metabolism
• Adverse effects :-
Anorexia, drowsiness and allergic reactions
• USES:-
• Tapeworm infection-DOC
• Flukes(schistosomiasis)
• Neurocysticercosis-as second choice to Albendazole
• Contraindication:- ocular cysticercosis-blindness

14. Pyrantel pamoate:-
• Depolarizing neuromuscular blocking agent→ by persistent activation of nicotinic
receptors → resulted spastic paralysis in worms
• Also inhibits cholinesterase's
• Highly effective for roundworm, pinworm & hookworm infections
• Given orally but poor absorption
• USE:-
• Treatment of Ascariasis:- alternative to albendazole
• SE:-Rare nausea, vomiting , Diarrhoea, Headache

15. -:Diethylcarbamazine (DEC):-
• Most effective drug used in the treatment of Wuchereria bancrofti (Adult worm
of filariasis)
• MOA:- it damage the microfilarial membrane structure
• Also ↑ cell mediated immunity of human hosts & prevent resistance
• Pharmacokinetics:-
• Absorption:- rapidly via gastrointestinal tract
• Widely distributed in the body & metabolized by liver
• Excretion-urine ↑by Acidic pH
• Safe in pregnancy
• A/E:- Fever, lymphadenopathy, muscular pain, tachycardia and skin rashes,
allergic reactions( Mazzotti reaction)
• Caution:- start therapy with a small dose and then increase it gradually

16. • USES:-
1. Filariasis-DOC
• DEC 6mg/kg + 400mg Albendazole or 400mg Ivermectin (every 6-12 month)
• Dose-orally 100mg TDS for 3 weeks
• Combination therapy (Triple-drug therapy-IDA) → single dose for 3year
• (Ivermectin, Diethylcarbamazine, and Albendazole )→ 95% parasite cleared was
as safe and well tolerated
• ↓Transmission of filariasis
2. Topical pulmonary eosinophilia→ DEC-100mg TDS
3. Subcutaneous & ocular filariasis
4.Dermal filariasis- high dose 8-10mg/kg for 3-6weeks

17. Pharmacotherapy of Neurocysticercosis/Cysticercosis
• Cysticercus → larval form of tape worm
• Occurs larval form migrates from gut to brain through blood
• Larvae converted to cysts & deposited at various site resulted in
• Dermal cysticercosis , Visceral Cysticercosis, ocular & neuro- Cysticercosis
• Symptoms of neuro- Cysticercosis:-
• Convulsion, & other neurological manifestation
• RX:-
1. Anthelmintic drug:- Albendazole (800mg BD for 8-15 days) & Praziquantel
(15-30 days)
Albendazole is preferred over Praziquantel
• Advantages:-
High cure rate & shorter duration treatment

18. 2. Other drugs:-
A. Prednisolone – 40-60mg daily
• Steroid therapy:- start 2 days before the anthelminthic drug & cont. 1-2 week
after
• Advantages:-
Use to prevent exaggerated host inflammatory response to dying parasites
↑Absorption of Albendazole
B. Anti-epileptic Drugs:- Carbamazepine
Precaution:-
↑Dose of Anthelminthic drug due to Enzyme inducer effect of Carbamazepine
Should be given with food (↑Absorption)

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