Anti-malarials

Question 1

What are the three stages in treatment of malaria?

Answer 1

• prophylaxis
• treatment of acute attack
• radical cure

Question 2

How do the quinoline derivatives work?

Answer 2

Accumulates in parasite’s food vacuoles, disrupts heme polymerization, causes oxidative damage to membranes and digestive proteases

Question 3

What allows the quinoline derivatives to stay in the food vacuole?

Answer 3

Gradient of decreasing pH (quinolines are basic drugs)

Question 4

What is the mechanism of chloroquine resistance?

Answer 4

Point mutations enable PfCRT to expel chloroquine through an energy-dependent efflux mechanism

Question 5

What is amantidine used for and how does it work?

Answer 5

Positive charge prevents chloroquine efflux from a chloroquine resistant parasite.

Question 6

What is primaquine used for and how does it work?

Answer 6

Treatment of relapses of malaria and a radical cure

• works by forming quinoline-quinone intermediates that oxidize schizont membranes

Question 7

How do pyrimethamine and chloroguanide work?

Answer 7

Inhibit dihydrofolate reductase, used as combination with atovaquone to treat malaria

Question 8

How does atovaquone work?

Answer 8

Depolarizes parasitic mitochondria and inhibits their electron transport. Used in combination with chloroguanide for prophylaxis and treatment of malaria

Question 9

How does artesunate work?

Answer 9

specific inhibitor of SERCA in P. falciparum

Question 10

One of your patients is taking primaquine for malaria and quickly becomes anemic. What underlying condition do you suspect they have?

Answer 10

G6PD deficiency

Question 11

What antimalarials are used in chloroquine-resistant regions?

Answer 11

mefloquine, doxycycline, atovaquone/proguanil

Question 12

A patient presents with severe malaria. What are your treatment options?

Answer 12

• IV quinidine + tetracycline + doxycyclin or clindamycin
• IV artesunate followed by atovaquone/proguanil, doxycyclin, or mefloquine
• exchange blood transfusion (parasite density > 10%, altered mental status, pulmonary edema, or renal complications)

Question 13

What is the main treatment of uncomplicated malarial infection of chloroquine sensitive strains of P. falciparum, P. malariae, or P. knowlesi?

Answer 13

Chloroquine

Question 14

What is the main treatment of uncomplicated malarial infection of chloroquine sensitive strains of P. vivax or P. ovale?

Answer 14

Chloroquine + primaquine

Question 15

What is the main treatment of uncomplicated malarial infection of chloroquine resistant strains of P. falciparum?

Answer 15

Atovaquone/proguanil

Question 16

What is the main treatment of uncomplicated malarial infection of chloroquine resistant strains of P. vivax?

Answer 16

Quinine + either doxycyclin or tetracycline + primaquine

Question 17

What is unique and awesome about primaquine?

Answer 17

Only drug that inhibits exoerythrocytic schyzogeny

Question 18

Your patient started anti-malarial treatment a few days ago and keeps calling you because he CANNOT stop itching, and his eyes feel a little funny. Which antimalarial drug is he taking?

Answer 18

Chloroquine

Question 19

You patient started anti-malarial treatment a few days ago and is complaining because he is feeling light headed and his wife keeps asking why he looks so yellow. What antimalarial drug is he taking?

Answer 19

Quinine