antihelminths

Question 1

Classification of helminths and possible targets for helminths (3)

Answer 1

• Nematodes – roundworms
• Trematodes - flukes
• Cestodas – tapeworms

Possible drug targets in helminths

• neuromuscular coordination
• carbohydrate metabolism
• mikrotubule integration

Question 2

Benzimidazoles, name 3.
mechanism:
good against: 2
Given:
Adverse- 4

Answer 2

Albendazole, mebendazole, tiabendazole

mechanism: inhibit the polymerization of the β-tubulin of microtubules → paralysis
- good against roundworms (nematodes) and tapeworms (cestodas)
- orally given
- adverse effects: GI, hepatotoxicity, visual disturbances
- teratogenic

Question 3

Ivermectin (Avermectin-Nobel prize!):
Mechanism:
Given:
ADverse effects- 
Effective against

Answer 3

• enhances GABA effect in the worm → paralysis
• orally given, does not cross BBB
• adverse effects: mild, due to the disintegration of the worms (fever, headache, dizziness, itching, joint pain)
• effective against certain roundworms: filarial Loa loa, Ascaris lumbricoides, Ancylostoma duodenale, Trichuris trichiura

Question 4

Levamisol.
mechanism
Given
adverse- 2
good against

Answer 4

• depolarizing neuromuscular blockade → paralysis
• orally given
• adverse effects: GI, mild neurological
• effective against some roundworms: Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale

Question 5

Praziquantel
mechanism
given
adverse
indicated

Answer 5

increases Ca++ permeability → spastic paralysis

• orally given, penetrates BBB
• adverse effects: GI, dizziness (mild)
• indicated mainly againts flukes and tapeworms: Schisostoma, Fasciola hepatica, Taeniatel

Question 6

Niclosamide
mechanism
given
effective against

Answer 6

• inhibits oxidative phosphorilation
• orally given, poor absorbtion
• side effects: GI, dizziness (mild)
• effective againts tapeworms: Taenia solium, Taenia saginata

Question 7

Pyrantel pamoat
mechanism
given
side effects- 2
good against

Answer 7

• releases acetylcholine in the worm, inhibits acetylcholinesterase →
  depolarizing blockade → spastic paralysis
• given orally, poor absorbtion
• side effects: GI (middle severe), CNS (mild)
• good againts: Ascaris, Necator, Ancylostoma, Enterobius

Question 8

Bithionol
mechanism
given
Side effects- 3
indicated

Answer 8

• inhibits oxidative phosphorylation
• orally given, penetrates BBB
• side effects: GI, CNS (dizziness, headache), toxic hepatitis
• indicated in fascioliasis (Fasciola hepatica