Anthelmintic drugs are used to kill or expel parasitic worms. Common anthelmintics discussed include mebendazole, albendazole, pyrantel pamoate, piperazine, levamisole, diethylcarbamazine citrate, ivermectin, niclosamide, and praziquantel. These drugs have different mechanisms of action and are used to treat a variety of helminth infections that are prevalent globally, especially in developing areas with poorer hygiene. Common side effects include gastrointestinal upset.

1. Anthelmintic Drugs

2. Anthelmintic are drugs that either
kill(vermicide) or expel (vermifuge) infesting
helminths.
Helminthiasis Is Prevalent Globally
More Common In Developing Countries
With Poorer Personal And Environmental
Hygiene

3. Drugs :
1) MEBENDAZOLE
2) ALBENDAZOLE
3) THIABENDAZOLE
4) TRICLABENDAZOLE
5) PYRANTEL PAMOATE/OXANTEL PAMOATE
6) PIPERAZINE
7) LEVAMISOLE/ TETRAMISOLE
8) DIETHYLCARBAMAZINE CITRATE
9) IVERMECTIN
10)NICLOSAMIDE
11)PRAZIQUANTEL

4. Mebendazole
Benzimidazole, congener of thiabendazole
Broad-spectrum anthelmintic activity
Less toxicity
Effective against Enterobius,Trichinella
Spiralis,Echinococcus and Trichuris infestations
Less active on Strongyloides

5. Mechanism of Action
1) It binds to β-tubulin of susceptible worms with high
affinity and inhibits its polymerization. Intracellular
microtubules in the cells of the worm are gradually
lost.
2) Blocks glucose uptake in the parasite and depletes its
glycogen stores.
3) Ovicidal against hookworms, roundworms and
whipworms

6. Pharmacokinetics
Poorly absorbed from GIT
Absorption is increased with fatty meal
Undergoes high first pass metabolism
t1/2 2-6 hrs
Adverse effects
Diarrhoea, nausea, abdominal pain .
High doses: Allergic reactions, loss of hair,
granulocytopenia
Contraindicated in Pregnancy

7. Uses and administration
For children above 2 years as for adults; ½ dose for 1–2 yr
age.
Roundworm
 Hookworm
Whipworm
 Upto 7 day treatment may be needed in heavy
trichuriasis.
100 mg twice a day for 3 days.

8. Pin worm (Enterobius) :100 mg single dose, repeated
after 2–3 weeks
Trichinosis: 200 mg BD for 4 days.; less effective
than albendazole.
 Hydatid disease: 200–400 mg BD or TDS for 3–4
weeks; less effective than albendazole.

9. Albendazole
congener of mebendazole
Spectrum of activity same as mebendazole with additional
larvicidal action against echinococcus, cysticerci, ascaris,
ancylostoma
Pharmacokinetics
Absorption increased with fatty meal
converted by first pass metabolism to its sulfoxide
metabolite which has potent anthelmintic action.
widely distributed in the body, enters brain
excreted in urine
 t½ of 8.5 hours.

10. Adverse effect
Dizziness
headache, fever, alopecia, jaundice, and neutropenia seen
on prolonged use
Uses
For intestinal worms it should be given on empty
stomach, while for cysticercosis, hydatid and cutaneous
larva migrans it should be given with fatty meal.
Ascaris, hookworm, Enterobius and Trichuris: a single
dose of 400 mg

11. Tapeworms and strongyloidosis: 400 mg daily for 3 days.
Neurocysticercosis: Usually 8–15 days course of 400 mg
BD (15 mg/kg/day).
Cutaneous larva migrans: Albendazole 400 mg daily for 3
days.
Hydatid disease: 400 mg BD for 4 weeks, repeat after 2
weeks (if required), up to 3 courses.

12. Lymphatic Filariasis: 400mg single dose Added to
diethylcarbamazine or ivermectin
Embryotoxic, hence contraindicated in pregnancy
Given with caution to patients with hepatic or renal
disease.

13. Thiabendazole
Broad spectrum benzimidazole
anthelmintic, not in much use due to
toxicity
Adverse effects: allergy, nausea, vomiting,
abdominal pain, diarrhoea, giddiness,
impairment of alertness etc
Drug of choice for strongyloidiasis and
cutaneous larva migrans

14. Triclabendazole
Effective only against fasciola hepatica and paragonimus
species
Rapidly absorbed, food increases bioavailability
More than 99% plasma protein bound
Adverse effects: abdominal cramps, diarrhoea, biliary
colic and transient headache
Indication: Fascioliasis and Paragonimiasis

15. Pyrantel Pamoate
Effective against Ascaris, Enterobius and Ancylostoma
Inactive against Trichuris.
Mechanism of action
Pyrantel causes activation of nicotinic cholinergic
receptors in the worms resulting in persistent
depolarization → slowly developing contracture and
spastic paralysis
Only 10-15% of drug absorbed, partly metabolised and
excreted in urine

16. Use and administration
For Ascaris, Ancylostoma, Enterobius: a single dose of 10
mg/kg
For Necator, Strongyloides: 10mg /kg for 3 days
Adverse effects: occasional G.I symptoms, headache and
dizziness
Oxantel pamoate
Very effective against Trichuris Trichiura
10mg/kg single dose

17. Piperazine
Highly active drug against Ascaris and Enterobius.
It blocks ach at neuromuscular junction and produces
neuromuscular block leading to flaccid paralysis in worms
and worms are expelled alive
Antagonistic with pyrantel pamoate
Readily absorbed, excreted in urine
Adverse effects : nausea, vomiting, abdominal discomfort
urticaria , dizziness.
Dose
For roundworm infestation 4 g OD for 2 days.

18. Levamisole, Tetramisole
Active against many nematodes, but use is restricted to
ascariasis and ancylostomiasis as a second line drug.
The ganglia in worms are stimulated causing tonic
paralysis and expulsion of live worms.
Interferes with carbohydrate metabolism
Dose
Ascariasis:150mg single dose
Ancylostomiasis: Two doses at 12 hrs intervals

19. Adverse effects
Nausea
Abdominal pain
Giddiness
Fatigue
Drowsiness or insomnia

20. Diethylcarbamazine citrate DEC
Effective against adult worm and microfilaria of
Wuchereria bancrofti, Brugia malayi, Loa Loa and also
microfilaria of onchocerca volvulus.
DEC causes alteration of organelle membranes of the
Mf promoting cell death. It is also suggested that
muscular activity of Mf and adult worms is affected so
that they are dislodged.
Readily absorbed, metabolised in liver
Excreted in urine
t½ 4-12hrs

21. Use
Filariasis: 2mg/kg tds after meals for 3 weeks
Tropical pulmonary eosinophilia: DEC (2-4mg TDS) for 2-3
weeks.
Adverse effects
Nausea, loss of appetite, headache, weakness and
dizziness

22. Ivermectin
Extremely potent semisynthetic derivative of the
antinematodal principle obtained from Streptomyces
avermitilis.
 Causes opening of chloride channels causing influx of cl
followed by worm paralysis and death
Microfilarial,not macrofilirial
Effective in cutaneous larva migrans and ascariasis, also
active against enterobius, trichuris
Only drug effective orally in scabies,pediculosis

23. Pharmacokinetics
Well absorbed orally
Highly plasma protein bound
Accumulates in tissues and liver
T1/2 16hrs
Excreted in faeces
Adverse effects
Fever,myalgia,light headedness,postural hypotension
Dose :Filariasis 10-15mg SD with 400mg albendazole
Scabies 0.2mg/kg SD

24. Niclosamide
Effective against adult tapeworms; T.saginata, T.solium,
Hymenolepsis.nana and Diphyllobothrium.latum
Inhibits mitochondrial oxidative phosphorylation, stops
ATP synthesis, energy depletion and cell death
Indication: Taeniasis 2g SD,
Hymenolepiasis 2g for 7days

25. Praziquantel
Effective against cestodes and trematodes
It increases the Ca permeability in the worms,
thereby increasing the muscle contraction, leading to
paralysis and detachment of worms
Interferes with glucose metabolism in Schistosoma
Rapidly absorbed, food increases bioavailability
Pronounced first pass effect
Crosses blood brain barrier

26. Adverse effects
Nausea, vomiting, headache, pruritus
Indication
Taeniasis, cysticercosis, fasciolliasis,
Paragonimiasis, schistosomiasis,
Hymenolepsis, diplyllobothriasis
Dose: 5-25mg/kg SD