This document provides information on various anthelmintic drugs used to treat helminth infections. It begins by introducing that anthelmintics are drugs that kill or expel helminths. Around 1/3 of the world's population is affected by helminthiasis, most commonly in developing countries with poor sanitation. Some common anthelmintic drugs discussed include mebendazole, albendazole, piperazine, pyrantel pamoate, and their mechanisms of action and use against specific helminth infections. Side effects and important considerations for each drug are also summarized.

1. ANTHELMINTICDRUGS
Ms Shivani Thakur
Associate Professor

2. Life cycle of Helminths

4. INTRODUCTION
• Anthelmintics are drugs that either kill (vermicide) or
expel (vermifuge) infesting helminths.

5. • Helminthiasis is prevalent globally (1/3rd of world’s
population), but is more common in developing
countries with poorer personal and environmental
hygiene. In the human body, GIT is the abode of
many helminths, but some also lives in tissues, or
their larvae migrates into tissues.
• Helminthiasis is rarely fatal, but is the major cause of
ill health.

6. The various Anthelmintic Drugs are:
• Mebendazole
• Albendazole
• Pyrantel pamoate
• Piperazine
• Levamisole, Teramisole
• Diethyl carbamazine citrate (DEC)
• Ivermectin
• Niclosamide
• Praziquantel

7. Common worm infestations and
drug of choice are:
WORM FIRST CHOICE DRUG
1. Round worm
2. Hook worm
3. Thread worm
4. Whip worm
5. Trichinella spiralis
6. Filarial
7. Guinea worm
8. Tape worm
9. Hydatid disease
 Mebendazole, Albendazole, Pyrantel
 Pyrantel, Mebendazole, Albendazole
 Pyrantel, Mebendazole, Albendazole
 Mebendazole
 Albendazole
 Diethyl carbamazine, Ivermectin
 Metronidazole
 Praziquantel, Niclosamide, Albendazole
 Albendazole

8. 1. MEBENDAZOLE:
• It is a broad spectrum anthelmintic and
produce nearly 100% cure rate/reduction in
egg count in roundworm, hookworm,
Enterobius and Trichuris infestations, but is
much less active on Strongyloides.
• Action of mebendazole will takes 2-3 days to
develop.
• It blocks the glucose uptake in parasites and
deplete its glycogen stores. Intracellular
microtubules in the cells of the worm are
gradually lost. It binds to Beta-tubulin of
susceptible worms with high affinity and
inhibits its polymerization.

9. DRUG MECHANISM OF ACTION INDICATIONS,
CONTRAINDICATIONS &
SIDE-EFFECTS
1. TRADE NAME:
Vermox
PHARMA NAME:
Mebendazole
CLASS:
Anthelmintic
Irreversibly blocks
glucose uptake by
susceptible helminths,
depleting glycogen
stores needed for
survival and
reproduction of the
helminths, causing
death.
INDICATIONS:
Treatment of;
•Trichuris trichiura
(whipworm)
•Enterobius vermicularis
(pinworm)
•Ascaris lumnricosides
(roundworms)
• Ancylostoma duodenale
(common hookworm)
• Necator americanus
(American hookworm)

10. DRUG MECHANISM OF
ACTION
INDICATIONS,
CONTRAINDICATIONS & SIDE-
EFFECTS
DOSAGE:
Adult:
Trichuriasis, Ascariasis,
hookworm infections:
100 mg twice a day for 3
consecutive days.
Enterobiasis: 100 mg
single dose, repeat after
2-3 weeks.
Paediatrics:
Safety and efficacy for use
in children <2 year not
established.
CONTRAINDICATIONS:
Allergy to mebendazole
Pregnancy (embryotoxic
and teratogenic; avoid
use, especially during 1st
trimester)
Lactation

11. DRUG MECHANISM OF
ACTION
INDICATIONS,
CONTRAINDICATIONS & SIDE-
EFFECTS
SPECIAL PREPARATION AND
ADMINISTRATION:
•Chew or swallow whole or
crushed and mixed with food.
•Arrange for 2nd course of
treatment if patient is not
cured 3 wks after treatment.
•Treat all family members for
pinworm infestation.
•Use strict hand washing and
hygiene measures.
•Disinfect toilet daily.
•Report fever, return of
symptoms, severe diarrhoea.
SIDE EFFECTS:
GI: Transient abdominal
pain, diarrhoea
General: Fever

12. 2. ALBENDAZOLE:
• It has broad-spectrum activity and excellent tolerability.
It is having single dose treatment in many cases.
• One dose treatment has produced cure rates in
Ascariasis, Hookworm and Enterobiasis, which are
comparable to 3 days treatment with Mebendazole.It is
more effective than Mebendazole.

13. • 3 days treatment has been found necessary for
Tapeworms including Hymenolepis nana.
• Absorption: After oral administration, Albendazole is
converted to its sulfoxide metabolite, which is active.
Albendazole sulfoxide is widely distributed in the body,
enters brain and is excreted in urine a t ½ of 8.5 hours.
Thus, Albendazole is able to exert antihelmintic activity in
tissue as well.
• Albendazole is well tolerated; only gastrointestinal side-
effects have been noted.

14. DRUG MECHANISM OF ACTION INDICATIONS,
CONTRAINDICATIONS &
SIDE-EFFECTS
2. TRADE NAME:
Albenza
PHARMA NAME:
Albendazole
CLASS: Anthelmintic
DOSAGE IN
PAEDIATRICS:
400 mg orally once as
a single dose ( in
Ascariasis,
Trichostrongylosis,
Pinworm Infection)
Inhibit the polymerization
of the parasite tubulin into
microtubules. The loss of
the cytoplasmic
microtubules leads to
impaired uptake of glucose
by the larval and adult
stages of the parasites. The
worm is then unable to
maintain energy
production, which leads to
immobilization and
eventual death .
INDICATIONS:
Used to treat certain
tapeworm infections
(e.g.,
neurocysticercosis).
Hydatid Disease
CONTRAINDICATIONS:
Allergy to albendazole
or other benzimidazole
anthelmintic drugs
(e.g., mebendazole)
Pregnancy and
lactation

15. DRUG MECHANISM OF
ACTION
INDICATIONS,
CONTRAINDICATIONS &
SIDE-EFFECTS
Tapeworm, Trinchinosis &
Strongyloidosis: 400 mg daily
for 3 consecutive days.
Neurocysticercosis: 1 month
treatment with 15 mg/kg
daily.
Hydatid disease: 400 mg BD
for 1 month, repeat after 2
weeks (if required), upto 3
courses.
SIDE EFFECTS:
CNS: Headache,
dizziness/vertigo, raised
intracranial pressure,
meningeal signs.
GI: Abdominal pain,
nausea and vomiting
Hepatic: Hepatic
abnormalities, acute liver
failure, elevations of
hepatic enzymes and
hepatitis

16. DRUG MECHANISM OF
ACTION
INDICATIONS,
CONTRAINDICATIONS &
SIDE-EFFECTS
SPECIAL PREPARATION AND
ADMINISTRATION:
•Take on an empty stomach, 1 hr
before or 2 hr after meals.
•Tell your doctor your medical
history, especially of: liver
disease, biliary tract problems
(e.g., blockage), blood/bone
marrow disorders. This
medication may cause liver
problems.
•Use strict hand washing and
hygiene measures. Disinfect
toilet daily.
•Dizziness, tremors, weakness
may occurs, so avoid driving or
operating dangerous
equipments.
Renal: Acute renal failure
Derm: Alopecia, Erythema
multiforme and Stevens-
Johnson syndrome
Misc: Hypersensitivity side
effects have included
hypersensitivity reactions
(including rash and
urticaria)

17. 3. Piperazine citrate
• Introduced in 1950, it is highly active drug against Ascaris and
Enterobius.
• Now a days it is considered as a second line drug for these
worms.
• It causes flaccid paralysis of these worms and then worms
expelled alive.
• No fasting or patient preparation is required.
• It is safe and well tolerated.

18. DRUG MECHANISM OF
ACTION
INDICATIONS,
CONTRAINDICATIONS &
SIDE-EFFECTS
3. TRADE NAME: Entacyl
PHARMA NAME:
Piperazine citrate
CLASS: Anthelmintic
DOSAGE IN PAEDIATRICS:
Ascariasis: 75 mg/kg PO as
a single daily dose for 2
consecutive days. Max.
daily dose of 3.5 gm.
Enterobiasis: 65 mg/kg PO
in a single daily dose for 7
consecutive days (max.
daily dose of 2.5 gm). In
severe infections, repeat
treatment after 1 wk.
Paralyzes ascarids by
hyperpolarizing
ascarid muscles; the
ascarids are then
dislodged and
expelled from the
intestine through
peristalsis.
Mechanism of action
against Enterobius is
not understood.
INDICATIONS:
Treatment of;
•Enterobius (pinworm)
•Ascaris (roundworms)
CONTRAINDICATIONS:
•Allergy to piperazine
•Renal or hepatic
disfunction
•Convulsion disorders
•Pregnancy and lactation
USE CAUTIOUSLY WITH;
•Anemia
•Malnutrition

19. DRUG MECHANISM OF
ACTION
INDICATIONS,
CONTRAINDICATIONS &
SIDE-EFFECTS
SPECIAL PREPARATION AND
ADMINISTRATION:
•Take on an empty stomach, 1
hr before or 2 hr after meals.
•Treat all family members for
pinworm infestation.
•Use strict hand washing and
hygiene measures. Disinfect
toilet daily.
•Dizziness, tremors, weakness
may occurs, so avoid driving or
operating dangerous
equipments.
•Take small and frequent
meals.
•Report skin rash, joint pain,
headache, weakness, tremors,
vision changes, severe GI
upset.
SIDE EFFECTS:
CNS: Headache, vertigo,
ataxia, tremors, muscular
weakness, seizures, ECG
abnormalities, memory
defect, cataract, blurred
vision, nystagmus, paralytic
strabismus
GI: Nausea, vomiting,
abdominal cramps, diarrhoea
Hypersensitivity reactions:
Urticaria, erythema, purpura,
fever, eczematous skin
reactions, lacrimation,
rhinorrhea, cough,
bronchospasm

20. 4. Pyrantel pamoate
• This polyanthelmintic has high efficacy against Ascaris, Enterobius
and Ancylostoma comparable to that of mebendazole.
• Low cure rates in case of Necator infestation.
• Less active against Strongyloides and inactive against Trichuris or
other worms.
• It causes hyperpolarization and flaccid paralysis of the worm.

21. DRUG MECHANISM OF
ACTION
INDICATIONS,
CONTRAINDICATIONS &
SIDE-EFFECTS
4. TRADE NAME: Antiminth,
Combantrin (CAN)
PHARMA NAME: Pyrantel
pamoate
CLASS: Anthelmintic
DOSAGE:
Ascaris, Ancylostoma and
Enterobius: 10 mg/kg single
dose.
Necator & Strongyloides: 3
days course of Pyrantel
pamoate 10 mg/kg.
Safety and efficacy not
established for children <2
yrs.
A depolarizing
neuromuscular
blocking agent that
causes spastic
paralysis of
Enterobius
vermicularis and
Ascaris
lumbricoides.
INDICATIONS:
Treatment of;
Enterobius vermicularis
(pinworm)
Ascaris lumnricosides
(roundworms)
CONTRAINDICATIONS:
Allergy to Pyrantel
pamoate
Pregnancy
Lactation

22. DRUG MECHANISM OF
ACTION
INDICATIONS,
CONTRAINDICATIONS &
SIDE-EFFECTS
SPECIAL PREPARATION AND
ADMINISTRATION:
•Administer drug with fruit
juice or milk; ensure that
entire dose is taken at once.
•Treat all family members for
pinworm infestation.
•Use strict hand washing and
hygiene measures. Disinfect
toilet after patient use.
•Launder bed linens, towels,
night clothes & undergarments
daily.
•Report skin rash, joint pain,
severe GI upset, severe
headache, dizziness.
•Take small & frequent meals.
•Avoid driving.
SIDE EFFECTS:
CNS: Headache, dizziness,
drowsiness, insomnia
GI: Anorexia, nausea,
vomiting, abdominal cramps,
diarrhoea, gastralgia,
tenesmus, transient elevation
of SGOT.
DERM: Rash