This document summarizes a lecture on anthelminthic and anti-protozoal drugs. It discusses how these drugs work, how they are classified based on the organisms they target, and provides examples of specific drugs. Key drugs discussed are albendazole and metronidazole. Albendazole works by paralyzing helminths through binding to microtubule proteins. Metronidazole kills protozoa by interfering with their energy production. Both drugs are generally well tolerated though can cause gastrointestinal side effects.

1. Anthelminthic & Anti-
Protozoal Drugs
Dr. Pravin Prasad
M.B.B.S., MD Clinical Pharmacology
Lecturer, Lumbini MedicalCollege &TH
12 April 2019 (29 Chaitra 2075)
Friday

2. By the end of this class, BSc. Nsg. I
year students will be able to:
Classify anthelminthic and anti-protozoal
drugs
Explain the mechanism of action of
albendazole and metronidazole
List the uses and adverse effects of
albendazole and metronidazole

3. Anthelminthic drugs
These drugs are active against helminths
(worms)
Acts by:
Kills the worm (Vermicidal)
Expels the worm (Vermifuge)
Classified on the basis of organism
susceptible

4. Anthelminthic drugs: classification
For roundworm, hookworm, pinworm
Albendazole, mebendazole, pyrantel
pamoate, piperazine, levamisole
For threadworm
Ivermectin, albendazole
For whipworm, Trichinella spiralis
Albendazole, Mebendazole

5. Anthelminthic drugs: classification
For Filariasis
Diethylcarbamazine, Ivermectin,
Albendazole
ForTapeworm
Praziquantel, Niclosamide,Albendazole
For Hydatid disease
Albendazole, Mebendazole

6. Albendazole
Broad spectrum anthelmintic
Acts by:
Binds to microtubular protein β-tubulin of
the parasite
Inhibits polymerization of microtubules
Microtubules gradually lost and
paralysed

7. Albendazole
Additional actions:
Blocks glucose uptake by parasite
Depletes glycogen stores by inhibiting
mitochondrial enzymes

8. Albendazole: Uses
Drug of choice:
Roundworm (Ascaris lumbricoides)
Hookworm (Ancyclostoma duodenale)
Tapeworm (Neurocysticercosis)
Pinworm (Enterobius vermicularis)
Hydatid disease (Echinococcous sps.)
Cutaneous larva migrans (Ancyclostoma
caninum)
Trichinella spiralis

9. Albendazole: Uses
Alternative drug for:
Threadworm (Strongyloides stercoliasis)
Whipworm (Trichuris trichiura)
Filaria (Wuchereria bancroftii, Brugia
malayi)
Tapeworm (Taenia sps., Hymenolepsis
nana)

10. Albendazole: Side effects
Excellent tolerability
Gastrointestinal side effects:
Nausea, diarrhoea, abdominal pain
Dizziness
On prolonged use:
Headache, fever, alopecia, jaundice,
neutropenia

11. Anti-protozoal drugs
These agents are active against protozoa
Unicellular
Non-photosynthetic
Belongs to the phylum Protozoa
Acts by killing the organism
Classified according to the organism
susceptible and site of action

12. Anti-protozoal drugs: Classification
Anti-amoebic drugs
Tissue amoebicides, Luminal amoebicides
Drugs for giardiasis
Metronidazole, Nitazoxanide, Quiniodochlor,
Furazolidine
Drugs for trichomonas
Metronidazole, Diiodohydroxyquin, Quiniodochlor,
Povidone-iodine
Drugs used in Leishmaniasis
Amphotericin B, Miltefosine, Sodium
stibogluconate,Paromomycin

13. Anti-amoebic drugs: Classification
Tissue amoebicides:
For intestinal + extraintestinal amoebiasis
Nitroimidazoles (-dazole)
Metronidazole,Tini-, Secni-, Orni-,
Satrani-

14. Anti-amoebic drugs: Classification
Tissue amoebicides:
For intestinal + extraintestinal amoebiasis
Alkaloids:
Emetine, Dihydroemetine

15. Anti-amoebic drugs: Classification
Tissue amoebicides:
For intestinal amoebiasis only
Chloroquine

16. Anti-amoebic drugs: Classification
Luminal amoebicides:
Amides
Diloxanide furoate, Nitazoxanide
8-hydroxyquinolines
Quinidochlor, Iodoquinol
Antibiotics
Tetracyclines, Paromomycin

17. Metronidazole
Broad spectrum amoebicidal drug
Not effective in aerobic bacteria and
aerobic environment

18. Metronidazole
Acts by:
Enters into cells by diffusion
Gets reduced to highly reactive nitro
radical
Competes with biological electron
acceptors for electrons generated by
pyruvate oxidation (PFOR pathway)
Cells become energy deficient and dies

19. Metronidazole: Uses
Amoebiasis (Entamoeba histolytica)
Giardiasis (Giardia lambia)
Trichomonas (Trichomonas vaginalis)
Anaerobic bacterial infection
Pseudomembranous enterocolitis
Acute necrotizing ulcerative gingivitis
(Trench mouth)
H. pylori gastritis

20. Metronidazole: Adverse effects
Frequent and unpleasant, but not serious
Anorexia, nausea, metallic taste,
abdominal cramps
Thrombophlebitis of injected vein
Dilute solution properly
Allergic reactions

21. Metronidazole: Adverse effects
Frequent and unpleasant, but not serious
Headache, glossitis, dryness of mouth
and impairment of concentration
Peripheral neuropathy and CNS effects on
prolonged administration
Seizures in high dose
Leukopenia on repeated doses

22. Conclusion
Anthelminthic and anti-protozoal drugs are
mainly classified on the basis of organism
susceptible
Albendazole acts by paralysing the
helminths
Metronidazole acts by making the protozoa
energy deficient

23. Conclusion
Albendazole is used as alternative drugs for
threadworm, whipworm and filaria
Metronidazole is active against anaerobic
organisms
Both drugs are well tolerated
Gastro intestinal side effects are common
for both

24. Any queries??
Lets have a break
With this, we have completed HIS-2
Next class will be taken by Dr. Naresh
Thank you!!