anti-parasitics

Question 1

Chloroquine

Answer 1

Anti-Malarial

Concentrated in acidic vacuoles of intraerythrocytic parasites –> inhibits heme polymerase –> damage to cell membrane via ferriprotoporphyrin IX

P falciparum resistance

AE: headache, confusion, N/V, dizziness

Question 2

Quinine

Answer 2

Anti-malarial

Unknown MOA (may be similar to chloroquine); oral

Use for chloroquine resistant malaria

AE: cinchonism (headache, tinnitus, N/V, blurred vision, flushing), rash, hemolysis (falciparum - “blackwater fever”)

Quinidine is IV version not in US

Question 3

Mefloquine

Answer 3

Anti-malarial

Inhibits protein synthesis of P. falciparum by targeting 80s ribosome

Prophylaxis, chloroquine-resistant malaria

AE: psychosis, anxiety, seizures, N/V, vivid dreams, cardiac conduction disturbances (not used frequently bc side effects!!!)

HL is 14 days!

Question 4

Doxycycline

Answer 4

Anti-malarial

Binds to bacterial ribosome 30S subunit –> inhibits protein synthesis

Doxy + quinine for acute P. falciparum

Prophylaxis

AE: phototoxicity

Question 5

Proguanil/Atovaquone

Answer 5

Anti-malarial

Proguanil: inhibits dihydrofolate reductase, concentrates in RBC

Atovaquone: uncouples oxidative metabolism

Resistance in Africa, SE Asia + expensive

Prophylaxis, chloroquine resistant

AE: pretty well tolerated (N/V, diarrhea @ high dose)

Question 6

Benzimidazole

Albendazole

Answer 6

Inhibits microtubule synthesis in nematodes –> impairs glucose uptake
Larvicidal (hydatid disease, neurocystericosis, ascariasis, hookworm)
Ovicidal (ascariasis, hookworm, whipworm)

Use: BROAD SPECTRUM: roundworm (ascariasis), whipworm (trichuriasis), pinworm (enterobiases), hookworm, taenia solium (tapeworm)

• Intestinal nematodes, T solium cysts in brain (neurocystericosis), echinococcosis (liver hydatid cysts)

AE: N/V

Question 7

Ivermectin

Answer 7

Potentiates opening of glutamate-gated Cl channels (only in nematodes + arthropods)

Nematodes: stronglyoides, onchocerca volvulus
Ectoparasites: scabies

Use: stronglyoidiasis, onchocerciasis (river blindness), scabies

AE: well tolerated (death of microfilaria can cause fever, pruritis, arthraliga, myalgia)

Question 8

Metronidazole

Answer 8

Concentrates within parasite –> acts as electron sink + directly damages DNA due to free radicals

Protozoans: Giardi, entamoeba, trichomonas

Entamoeba histolytica - amoebic liver abscess

AE: N/V, metallic tase, disulfiram like reaction