Anti parasites

Question 1

chloroquine

Answer 1

Anti-malaria drug

• historically was drug of choice, now so much resistance - rarely useful
• MOA: inhibits heme polymerase, so that FPP (a byproduct of hemoglobin degradation) does not become crystallized. uncrystallized it is toxic and kills the parasite
• Pharm: bitter taste, well absorbed PO, active against erythrocyte stage
• Tox: safe at prophylactic doses. if given IV, may cause HEART BLOCK

Question 2

ivermectin

Answer 2

treats: onchocerciasis (river blindness) and other nematodes, including intestinal stronyloides
- MOA: potentiates GABA action, inhibits oviposition. In mammals GABA only present in CNS, and this drug cannot cross BBB –> non toxic!

Question 3

mebendazole

Answer 3

treats: intestinal nematodes (not strongyloides)
- MOA: binds tubulin, blocking microtubule assembly (like albendazole)
- Pharm: POORLY ABSORBED FROM GI TRACT –> ineffective against systemic nematodes, but low toxicity :)

Question 4

quinine

Answer 4

anti-malaria drug

• more toxic and less effective than chloroquine (though treats chloroquine-resist strains)
• MOA: inhibits heme polymerase, so that FPP (a byproduct of hemoglobin degradation) does not become crystallized. uncrystallized it is toxic and kills the parasite
• Pharm: oral (bitter taste), active against erythrocyte stage
• Tox: CINCHONISM: reversible tinnitus, dec hearing, HA, visual disturbances; IV: may cause heart block like chloroquine

Question 5

trematode

Answer 5

fluke

Question 6

nemantode

Answer 6

roundworm

Question 7

fansidar (pyrimethamine + sulfadoxine)

Answer 7

anti-malaria drug

• MOA: folate antimetabolites
• not used so much b/c of SJS (very active, but TOXIC)
• Tox: SJS! is a sulfa drug!

Question 8

mefloquine

Answer 8

anti-malaria drug

• best drug for prophylaxis of chloroquine-resistant strains. erythrocyte form only
• Tox: psychosis (rarely)

Question 9

atavaquone + proguanil (malarone)

Answer 9

anti-malaria drug

• active against many resist strains
• MOA: inhibits pyrimidine synthesis
• Pharm: short t1/2
• Tox: no neurologic SEs (unlike mefloquine)

Question 10

thiabendazole

Answer 10

treats: DISSEMINATED strongyloides infection
- better absorbed (and thus more toxic) than mebendazole
- Tox: nausea, anorexia, other SEs

Question 11

cestode

Answer 11

tapeworm

Question 12

praziquantel

Answer 12

treats: most trematodes and cestodes; drug of choice for shistosomiasis)
- MOA: makes worms leaky to calcium, causing spastic paralysis
- well absorbed, well tolerated
- high cost (limiting for 3rd world countries)

Question 13

albendazole

Answer 13

treats: intestinal nematodes, neurocysticercosis, hydatid cyst disease, and echinococcal disease
- MOA: binds tubulin, blocking microtubule assembly (like mebendazole)
- Tox: rare, unless given at high dose (BM suppr)

Question 14

doxycycline

Answer 14

anti-malaria drug

• active against both chloroquine and mefloquine resistant strains
• prophylaxis and treatment
• Pharm: short t1/2 (daily dosing)
• Tox: stains teeth, photoxicity
• MOA: unknown … lol

Question 15

pyrimethamine

Answer 15

anti-malaria drug

• MOA: folate antimetabolite - inhibits dihyrdofolate reductase (DHFR) of parasite
• used as prophylaxis or in combo for treatment for cholorquine-res strains
• Tox: BM suppression (anti-folate. can be rescued w/ folinic acid – Leucovorin!)

Question 16

primaquine

Answer 16

anti-malaria drug

• MOA: kills liver hypnozoites (not active against erythrocyte forms)
• Pharm: oral (bitter taste), LIVER forms only!
• Tox: hemolysis in ppl w/ G6PD deficiency