Antiparasitics

Question 1

Mebendazole:

Answer 1

Uses: -Effective against many intestinal roundworms.

• Kills some ova.
• Low systemic bioavailability causes low incidence of SEs.

Question 2

Albendazole:

Answer 2

Uses: -Echinococcus.

• Neurocysticercosis due to pork tapeworm.
• Great against cutaneous larval migrans.

Question 3

Thiabendazole:

Answer 3

Uses:-Strongyloidiasis.

• Cutaneous larva migrans.
• Also effective against roundworms.

Question 4

Pyrantel pamoate:

Answer 4

Uses: -Pinworm, roundworm.

-Poorly absorbed.

Question 5

Praziquantel:

Answer 5

Uses: -Drug of choice for all species of Schistosoma.

• Some activity against other trematodes.
• Use for pork tapeworm, prevention of neurocysticercosis (also hits tapeworm eggs).

Question 6

Paromomycin sulfate:

Answer 6

Use: -Tapeworm infections, especially those who can’t tolerate other drugs.
-Luminal amebicide for intestinal amebiasis.

Question 7

Chloroquine:

Answer 7

MOA: Blood schizonticide. Selectively target intraerythrocytic trophozoites – inhibits heme polymerization within trophozoite, allowing heme to accumulate to toxic levels.

Uses: -Prevents attacks of all 4 species of malaria (except chloroquine-resistant P. falciparum).
-Hits P. malariae and chloroquine-sensitive P falciparum, but does not completely cure vivax and ovale.

SEs: Visual impairment.

Question 8

Mefloquine:

Answer 8

MOA: Blood schizonticide. Selectively target intraerythrocytic trophozoites – inhibits heme polymerization within trophozoite, allowing heme to accumulate to toxic levels.

Uses:-Treatment of multi-drug resistant P. falciparum.
-Used as prophylaxis in areas where organisms are chloroquine-resistant.

SEs: CNS effects, vestibular effects.
Contraindicated in patients with epilepsy or other psych disorders.

Question 9

Atovaquone + proguanil:

Answer 9

MOA: both drugs block pyrimidine synthesis.

Uses:Prevention and treatment of chloroquine-resistant P. falciparum.

Question 10

Quinine:

Answer 10

MOA: Blood schizonticide. Selectively target intraerythrocytic trophozoites – inhibits heme polymerization within trophozoite, allowing heme to accumulate to toxic levels.

Uses: -Blood schizonticide against all four malarial parasites (even chloroquine-resistant P. falciparum).
-Agent of choice against severe acute attacks.

SEs: -Cinchonism: headache, visual disturbance, dizziness, tinnitus.

• Cardiac effects.
• GI effects.

Question 11

Doxycycline:

Answer 11

MOA: Decrease malarial protein and pyrimidine synthesis.

Uses: -Multidrug-resistant P. falciparum

SEs: -GI effects.

• Candida superinfection.
• Photosensitization.
• -teeth discoloration – avoid use in kids.
• Contraindicated in pregnancy.

Question 12

Primaquine:

Answer 12

Uses: -Drug of choice for vivax and ovale; will kill dormant liver schizonts.

• Should be used in conjunction with blood schizonticide.
• Used in combination with clindamycin to treat pneumocystis pneumonia in AIDS patients.

SEs: -Hemolytic reactions in those with G6PD deficiency.

Question 13

Metronidazole:

Answer 13

• Tissue amebicide – for symptomatic infections of E. histolytica.
• Giardia
• Trichomonas vaginalis

Question 14

Iodoquinol:

Answer 14

-Use in combination with metronidazole for mild to severe infections of E. histolytica.

Question 15

Atovaquone:

Answer 15

MOA: Selective inhibitor of protozoal mitochondrial electron transport, ultimately affecting pyrimidine synthesis.

Uses: -Alternate treatment/prophylaxis for Pneumocystis.
-Toxoplasma gondii infections.

Question 16

Nitazoxanide:

Answer 16

MOA: Interferes with anaerobic energy metabolism.

Uses: -Giardia.
-Cryptosporidium parvum.