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
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
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
