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

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

3. Commonly encounterd trematode infections
Schistosomiasis

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

5. Drugs Benz-imidazoles Mebendazole Albendazole Thiabendazole
Pyrantel pamoate / Oxantel pamoate
Ivermectin
Diethylcarbamazine (table salt)
Praziquantel

6. 1. Benzimidazole: Mebendazole
Mechanism Of Action:
Inhibits polymerization of tubulin protein by binding to β-tubulin of intestinal & tegumental cells of worm(The tegmentum (from Latin for "covering") is a general area within the brainstem.;)
also inhibits fumarate reductase
Loss of cytoplasmic microtubules leads to up-take of microtubule dependent glucose & depletion of glycogen stores; no glucose no ATP; oxidation-phosphorylation in mitochondria
Result: No energy, no mobility, death of worm
(*polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks)*.

7. 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

8. USES:
Effective against 4 nematodes like, Pin, Round, Whip and hook worms (both variety)
For all these four types remember the DOC is mebendazole; with some exceptions

9. Now we want to know what these names, pin, round, whip and hooks are like.
1. Remember you can collect these pins on one sticky tape (associate it with children who are afraid of pins and needles and these vermicelli are as thin as pins and needles)
2. Now round is your ball Ascaris lumbricoides’ ball formation causing intestinal obstruction
3. Whip is TRICky (Trichiuris trichuria) and shapes just like the whip you use to make the horse run fast 4. Hooks are usually two; Necator americanus (nectar of flowers is sucked by insects) and Ancylostoma duodenale are hooked to intestinal wall to suck the blood

10. 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

11. 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

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

13. Ivermectin Uses Strongyloidiasis (due to Nematodes )
Elephantiasis (mass treatment) Elephantiasis is a disease that is characterized by the thickening of the skin and underlying tissues, especially in the legs, male genitals.
Onchocercus volvulus (DOC-Tropical disease of skin & underlying connective tissue)
Cutaneous larva migrans
Scabies

14. 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 (*A severe, potentially life-threatening allergic response that occurs within seven days of treatment of microfilariasis *)
In onchocerciasis: Skin edema, pruritus & mild eye irritation, headache, dizziness, abdomina pain
In combine onchocerciasis & heavy Loa-loa infection: Encephalopathy (Pion SD 2006),so do not use)
Don’t use in trypanosomiasis or meningitis

15. 4. Diethylcarbamazine Piperazine derivative
DOC for lymphatic filariasis (adult of W. bancrofti, B. 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

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

17. The End