1. Kaukab Azim, MBBS, PhD Modified by :Israa
Anthelminthic
Kaukab Azim, MBBS, PhD
Modified by :Israa

2. Commonly encountered nematode (roundworm) infections
Onchocerciasis (river blindness)
Enterobiasis (pinworm)
Ascariasis (roundworm)
Filariasis
Trichuriasis (whipworm disease )
Hookworm (ancylostoma duodanale)
Strongyloidiasis (threadworm)

5. Commonly encounterd trematode (Flukes) infections
Schistosomiasis

6. Commonly encounterd cestode (Tapeworms) infections
Echinococosis (hydatid disease).
Taeniasis
Cysticercosis

8. Drugs Benzimidazoles Mebendazole Albendazole Thiabendazole
Pyrantel pamoate / Oxantel pamoate
Ivermectin
Diethylcarbamazine (table salt)
Praziquantel

9. 1. Benzimidazole: Mebendazole
Mechanism Of Action:
Inhibits polymerization of tubulin protein by binding to β-tubulin of intestinal & tegumental cells of worm
Also inhibits fumarate reductase important in anaerobic respiration.
Loss of cytoplasmic microtubules leads to loss of up-take of microtubule dependent glucose & depletion of glycogen stores; no glucose no ATP; no oxidation-phosphorylation in mitochondria
Result: No energy, no mobility, death of worm

10. Mebendazole
Low bioavailability due to poor absorption and due to first pass effect
Co-administration with cimetidine increases mebendazole plasma levels
Decrease dose in liver impairment
Metabolites are active
Contraindicated in pregnancy due to teratogenicity & embryotoxicity in animals
USES:
Effective against 5 nematodes Pin, Round, Whip and hook worms (Necator americanus and Ancylostoma duodenale)

11. 2. Pyrantel Pamoate USE: For pin worm, round worm & hook worm
Oxantel pamoate (1dose) for Trichuriasis
MOA:
Depolarizing neuromuscular blockers, induce marked persistent activation of nicotinic (Ach) receptors of worm; open the cationic channels resulting in irreversible, spastic paralysis of worm;
it also inhibits cholinesterases
Low absorption (>85% passes in feces unaltered)
Safe for pregnant woman

12. 3. Ivermectin (Nippon Y. Zasshi, 2003 & Gyatt H, De S
3. Ivermectin (Nippon Y. Zasshi, 2003 & Gyatt H, De S. N Bundy,1997 May)
A semisynthetic anthelmintic
MOA:
Binds selectively and with strong affinity to GABA or glutamate-gated chloride ion channels in invertebrate nerve and muscle cells
Binding leads to Hyperpolarization of cell membrane
due to influx of chloride ions (glutamate)
due to GABA (direct release) & its receptor stimulation
Result: Paralysis of muscles & death of parasite

13. Ivermectin 93% plasma protein-bounded Excretion via GI route only
Poor CSF distribution
P-glycoprotein efflux pump
Resistance: Widespread use in sheep & cattle

14. Ivermectin Uses Strongyloidiasis Elephantiasis (mass treatment)
Onchocercus volvulus (DOC)
Cutaneous larva migrans
Scabies

16. Ivermectin
Adverse effects: not much; minimal in absence of parasitic infection
In filariasis: Fever, myalgia, lightheadedness, malaise & postural hypotension
Mazotti reaction in heavy infection due to dying microfilariae
In onchocerciasis: Skin edema, pruritus & mild eye irritation, headache, dizziness, abdominal pain
In combine onchocerciasis & heavy Loa-loa infection: Encephalopathy, do not use)
Don’t use in trypanosomiasis or meningitis

17. 4. Diethylcarbamazine Piperazine derivative
DOC for lymphatic filariasis (adult of W. bancrofti, Brugia malayi & loasis (best for loasis), tropical pulmonary eosinophilia of W. bancrofti and B. malayi, can be used in visceral larva migrans
MOA: Arachidonic acid metabolism interference
Adjust dose in renal dysfunction
Mazotti reaction in onchocerciasis

18. 5. Praziquantel Treatment of cestodes & trematodes
Increases Ca++ influx in tegumental cells causing tetanic contracture & loss of adherence to host’s tissue
Food & cimetidine facilitate absorption;
Extensive first pass metabolism
Anticonvulsants in cysticercosis & spasmolytic in abdominal pain

19. The End