Antihelmintics

Question 1

Mebendazole

Answer 1

Benzimidazole

Inhibits polymerization of helminth beta-tubulin, interfering with microtubule-dependent functions (like glucose uptake)

Pin, whip, round, and hook worms

GI disturbances

Question 2

Tiabendazole

Answer 2

Benzimidazole

Inhibits polymerization of helminth beta-tubulin, interfering with microtubule-dependent functions (like glucose uptake)

Pin, whip, round, and hook worms

GI disturbances

Question 3

Albendazole

Answer 3

Benzimidazole

Inhibits polymerization of helminth beta-tubulin, interfering with microtubule-dependent functions (like glucose uptake)

Pin, whip, round, and hook worms

GI disturbances

Question 4

Nitazoxanide

Answer 4

Also antiviral

Treatment of giardiasis and cryptosporidiosis

Inhibit pyruvate:ferredoxin oxidoreductase enzyme-dependent electron transfer, important for anaerobic energy metabolism

Question 5

Praziquantel

Answer 5

Treatment of flukes and onchocerciasis

Binds to consensus protein kinase C-binding sites in a beta-subunit of schistosome (fluke) voltage-gated calcium channels, inducing Ca2+ influx causing a rapid and prolonged contraction of the musculature, resulting in paralysis and death.

Dizziness
Abdominal distress

Question 6

Piperazine

Answer 6

Roundworm and threadworm treatment

GABA receptor agonist, causing nerve ending hyperpolarization, inducing paralysis

Urticaria
Seizures

Question 7

Pyrvinium

Answer 7

Pin worms only

Inhibition of mitochondrial complex 1 and interference of glucose uptake

GI disturbances

Question 8

Diethylcarbamazine

Answer 8

Derivative of piperazine

Used for elephantiasis

Unknown MOA – Altering helminth surface membrane, interfering with arachidonate metabolism

Allergic side effects related to dying filariae

Question 9

Niclosamide

Answer 9

Used in tapeworm – no activity for roundworms, pinworms, or hookworms

Diminishes potential of the inner mitochondrial membrane and inhibits/uncouples oxidative phosphorylation

Pruritis

Question 10

Levamisole

Answer 10

Roundworm treatment

Blocks neuromuscular junctions through stimulation, paralyzing worm

Agranulocytosis

Not used in North America

Question 11

Ivermectin

Answer 11

First choice for treatment of many filarial infections and onchocerciasis. Some roundworm activity, but no hookworms.

Opens glutamate-gated chloride channels and increasing Cl-, binding to GABA receptors or novel allosteric sites on acetylcholine nicotinic receptor cause increased transmission and paralysis

Skin rash/itching
Post-treatment encephalopathy