Malaria Drugs

Question 1

Name the 5 quinolone derivatives used for treatment of malaria or prophylaxis.

Answer 1

Quinine, Chloroquinine, Hydroxychloroquinine, Mefloquinine, Primaquine

Question 2

What is the mechanism of action of Quinine, Chloroquinine, Hydroxychloroquinine, and Mefloquinine?

Answer 2

1. Accumulate in parasite’s food vacuole

2. disrupt heme polymerization to hemozoin yielding oxidative damage to membranes and digestive proteases

Question 3

What is the mechanism of action of Primaquine?

Answer 3

formation of quinolone-quinone intermediates that oxidize shizont membranes
only drug that inhibits exoerythrocytic schyzogony

Question 4

What are some side effects of treatment with quinines?

Answer 4

Cinchonism (overdose of quinines resulting in headache, dizziness, hearing loss and ringing in ears) hypotension, hypoglycemia, abortion, and arrhythmias

Question 5

What are some side effects of treatment with chloroquinines?

Answer 5

itching and retinitis

Question 6

What are some side effects of primaquine treatment?

Answer 6

Hemolysis (G6PD), methemoglobinemia, nausea, vomitting and fever

Question 7

What is the mechanism of Amantadine?

Answer 7

Positive charge helps chloroquine overcome chloroquine-resistant malaria vacuoles and point mutations against amantadine return bacteria to chloroquine-sensitivity

Question 8

What is the mechanism of action of Artesunate and Artemether?

Answer 8

Inhibit SERCA in P. falciparum

Question 9

Which two drugs are often used in combination?

Answer 9

Artemether and lumefantrine

Question 10

Which drug can cause neurotoxicity and QT prolongation?

Answer 10

Artesunate

Question 11

What class of drugs is Atovaquone classified in and what is its mechanism of action?

Answer 11

napthalene; depolarizes the parasitic mitochondria and inhibits electron transport

Question 12

Name the 2 antifolate drugs used to treat Malaria and which enzyme they inhibit.

Answer 12

Chloroguanide and pyrimethamine; inhibit DHFR (human and parasitic)

Question 13

Name 3 antibiotics that can be used to treat malaria and describe why they would need to be used over the chloroquinones.

Answer 13

tetracycline, clindamycin, doxycycline; used for severe malaria and in chloroquinine resistant uncomplicated malaria

Question 14

Which of the 3 antibiotics used to treat malaria can cause photosensitivity?

Answer 14

doxycycline

Question 15

What are the clinical signs of malaria?

Answer 15

chills, fever, hepatosplenomegaly and parasites inn blood smears

Question 16

Name the 3 ways to treat malaria.

Answer 16

prophylaxis, tx acute attack, radical cure

Question 17

Which of the quinolines is used for radical cure of malaria?

Answer 17

Primaquine

Question 18

Why is chloroquine not widely used anymore?

Answer 18

because there was a spread of chloroquine resistant P. falciparum

Question 19

A defect in what enzyme is protective against malarial infections and why?

Answer 19

G6PD; cell dies from oxidative damage before the parasite can mature

Question 20

Which drugs would be used for malaria prophylaxis and in what order?

Answer 20

1. antimosquito measures
2. Chloroquine
3. Mefloquine if chloroquine resistant area
4. Doxycycline or Atovaquone/proguanil in mefloquine resistant area
5. Primaquine

Question 21

Most strains of P. falciparum in Africa are resistant to which drug?

Answer 21

chloroquine

Question 22

In which patients is treatment with Primaquine contraindicated?

Answer 22

G6PD deficient; they can develop a severe anemia