This document discusses anthelmintic drugs used to treat parasitic worm infections. It covers drugs that act on nematodes like benzimidazoles and levamisole, as well as those for cestodes and trematodes including praziquantel. Each drug's mechanism of action, dosing, and common adverse effects are outlined. A variety of anthelmintics are available to treat specific parasitic infections through mechanisms like inhibiting microtubule synthesis, altering parasite membrane permeability, or inducing paralysis. While generally well-tolerated, some drugs can cause gastrointestinal, neurological, or allergic side effects.

1. CHEMOTHERAPY
HIGHLIGHTS
MOHAMED BAHR; MD, PHD
Anthelmintic Drugs

2. Mohamed Bahr; MD, PhD
ANTHELMINTIC
DRUGS

3. Mohamed Bahr; MD, PhD

4. Mohamed Bahr; MD, PhD
I. DRUGS FOR
NEMATODES

5. Mohamed Bahr; MD, PhD
A. BENZIMIDAZOLES
Inhibit microtubules synthesis
→ interfere with glucose
uptake

6. Mohamed Bahr; MD, PhD
MEBENDAZOLE (ASCARIS,
ANCYLOSTOMA,
ENTEROBIUS, TRICHURIUS)
Enterobiasis: single 100-mg chewed tablet, repeated after 2 and
4 weeks.
• All family treated at the same time + general hygienic measures.
• Local application of white precipitate ointment around the anal
canal.
Other nematode infections: 100 mg twice daily for 3 successive
days.
• Fe is given in ankylostomiasis to correct the associated anemia.

7. Mohamed Bahr; MD, PhD
FLUBENDAZOLE
similar to mebendazole but also
effective in strongyloides

8. Mohamed Bahr; MD, PhD
ALBENDAZOLE (BROAD
SPECTRUM FOR NEMATODES
AND CESTODES)
Nematode infection (ascaris, ankylostoma, enterobius,
trichurius):
• Single oral dose 400 mg (repeat for 3 days for ascaris and in
2 wks for enterobius).
Cestode infection 1st choice in
• Hydatid disease.
• Neurocysticercosis: plus corticosteroids to ↓inflammatory
reaction to dying parasites.

9. Mohamed Bahr; MD, PhD
THIABENDAZOLE
Strongyloides (25 mg/kg twice/day for 2
days).
Trichinosis (for 5 days).
Cutaneous larva migrans (for 2 days).

10. Mohamed Bahr; MD, PhD
B. PYRANTEL
PAMOATE
Alternative
to mebendazole in ankylostoma, ascaris
and enterobius.

11. Mohamed Bahr; MD, PhD
C. LEVAMISOLE
Broad spectrum

12. Mohamed Bahr; MD, PhD
D. ANTIFILARIAL
DRUGS
Diethylcarbamazine
• Effective on blood microfilaria of Wuchereria bancrofti and Loa
loa.
• Diethylcarbamazine: alters surface structure of microfilariae
displacing them from tissues → ↑ destruction by host
defense mechanisms.
Ivermectin: well tolerated GABA
• 1st choice for onchocerciasis - strongyloidiasis.

13. Mohamed Bahr; MD, PhD
II. ANTIBILHARZIAL
DRUGS

14. Mohamed Bahr; MD, PhD
A. PRAZIQUANTEL (BROAD-
SPECTRUM FOR TREMATODES
AND CESTODES) CALCIUM
• Schistosomiasis: 1st choice in all species. 20 mg/kg /4-6 hrs (3
doses).
Cestodes
• Taeniasis: 1st choice (single dose of 5-10 mg/kg).
• H nana and D latum infection (1st choice).
• Neurocysticercosis (2nd choice to albendazole) plus
corticosteroids.
• Hydatid disease as an adjunct to albendazole pre- and post-
surgery.

15. Mohamed Bahr; MD, PhD
B. OXAMNIQUINE UK
(MANSONI) –
METRIFONATE OP
(HAEMATOBIUM);
RARELY USED

16. Mohamed Bahr; MD, PhD
III. DRUGS FOR CESTODES:
PRAZIQUANTEL – NICLOSAMIDE -
ALBENDAZOLE

17. Mohamed Bahr; MD, PhD
NICLOSAMIDE
(GLUCOSE)
2nd line to praziquantel for T saginata and solium, D latum
and H nana.
Dose: 2 g (4 chewed tablets), single dose on empty stomach.
inhibits glucose uptake and oxidative phosphorylation →
scolex loosening and worm expulsion

18. Mohamed Bahr; MD, PhD
PARALYSIS
Pyrantel Pamoate: depolarizing NMB → spastic paralysis → worm
expulsion.
Levamisole: depolarizing NMB and immunostimulant.
Ivermectin: ↑ GABA transmission (↑ Cl- influx).
Praziquantel: ↑ Permeability of worm cell membrane to Ca2+ →
contraction followed by spastic paralysis, dislodgement and death.
Metrifonate: organophosphorus ChEI → worm paralysis.
Oxamniquine: UK mechanism → paralysis→ hepatic shift and death.

19. Mohamed Bahr; MD, PhD
Benzimidazoles: inhibit microtubules synthesis → interfere
with glucose uptake.
Niclosamide: inhibits glucose uptake and oxidative
phosphorylation → scolex loosening and worm expulsion.

20. Mohamed Bahr; MD, PhD
ADVERSE EFFECTS
GIT
CNS
Hypersensitivity
Teratogenic

21. Mohamed Bahr; MD, PhD
Drug Adverse effect
Mebendazole/flubendazole
< 10 % absorbed
GIT pain and diarrhea
Teratogenic (mebendazole)
Albendazole GIT disturbances
CNS: headache – dizziness – insomnia
Hepatotoxicity - pancytopenia - alopecia (in treatment of
hydatid cyst)
Thiabendazole
Complete absorption → more toxic
GIT disturbances (ANV)
CNS effects
Skin reactions (fatal)
Teratogenic (CI in pregnancy)
Pyrantel Pamoate GIT disturbances (ANVD) mild
Levamisole GI upset
CNS effects
Hypersensitivity
Diethylcarbamazine GIT upsets (taken after meals).
CNS effects (headache) - arthralgia
Hypersensitivity to dying parasites: fever, rash, leukocytosis.
Praziquantel (well tolerated) GIT disturbances
CNS effects (headache - dizziness - drowsiness)
Hypersensitivity (rash, pruritus, malaise)
Low-grade fever -eosinophilia.
Teratogenic

22. Mohamed Bahr; MD, PhD

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25. Mohamed Bahr; MD, PhD
REFERENCES
Lippincott’s Illustrated Reviews, 5th ed.
Color Atlas of Pharmacology, 2nd ed.
Goodman and Gilman's The Pharmacological Basis of
Therapeutics, 12th ed.