Antimalarial Drugs

Question 1

Plasmodium Vivax

Answer 1

Low parasite burden, easier to take care of, mild anemia, can go into latent form for years, need radical tx. Most common outside Africa. Schuffner’s dots 48 hour recurring fever

Question 2

Plasmodium Ovale

Answer 2

Low parasite burden, easier to take care of, mild anemia, can go into latent form for years need radicle tx. Schuffner’s dots, 48 hour recurring fever

Question 3

Plasmodium Malariae

Answer 3

Low parasite burden, easier to take care of, mild anemia 72 hour recurring fever

Question 4

Plasmodium falciparum

Answer 4

Most deadly, most common in africa, high parasite burden, severe anemia, cerebral and multi-organ symptoms. gametes look like a sickle or curved banana shape. Forms a rosette and causes small vessels to clog off due and ischemia. Produces cytokine response, and can infect RBCs of any age. 24 hour recurring fever

Question 5

Order of infection

Answer 5

Sporozites from mosquito injected into body, migrate to liver. Enters hepatocytes and become schizonts, multiply and lyse the hepatocyte as merozoites and infect RBCs. They then enter the ring form, become trophozites, then Schizont, and lyse the RBC as Merozoites which can mature and produce gametes, or can reinfect another RBC. The Gametes reproduce in the mosquito.

Question 6

Schuffner’s dots

Answer 6

Dots seen in the cytoplasm of cells infected by P. ovale or P vivax

Question 7

Binding site for the merozoite to enter the RBC.

Answer 7

Glycophorin Receptor

Question 8

Fever waxing and waining

Answer 8

Is due to merozoite release from the RBCs.

Question 9

Chloroquine

Answer 9

Prophylaxis agent or tx. inhibits heme polymerase preventing the conversion of ferriptotoporphyrin to hemozolin causing toxic buildup in the cell. Can have dizzyness, headache, skin rashes, can cause serious eye dameage in extended large doses.

Question 10

Quinine

Answer 10

More toxic than chloroquine, but no resistance developed, used for resistant P. falciparum. Inhibits heme polymerase. AE: tinnitus, blurred vision, nausea, headache, decreased hearing aacuity, damage to vision balance and hearing.

Question 11

Quinidine

Answer 11

Often combined with Quinine. Antiarrhythmic drug which blocks Na and K currents. IV for severe malaria, AE: Cardiac problems

Question 12

Mefoquine

Answer 12

Inhibits heme polymerase. AE: neuropsychiatric reactions (disorientation, hallucinations, depression). Used only for chloroquine resistant P. falciparum.

Question 13

Atovaquone

Answer 13

MOA: depolarizes parasitic mitochondria and inhibits electron transport. Usually given with proguanil. Has drug interactions.

Question 14

Proguanil

Answer 14

Metabolite inhibits the plasmodial Dihydrofolate reductase. Enhances mitochondrial toxicity of atovaquone. Becomes concentrated in erythrocytes.

Question 15

Atovaquone-proguanil

Answer 15

Combination acts to depolarize parasitic mitochondrial ETC and DHFR. Has slow onset, expensive, GI disturbances. Replacing mefoquine for prophylaxis.

Question 16

Artemisinins

Answer 16

Heme iron in the malarial pigment acts on the drug to produce free radicals that damage parasite proteins. Inhibits calcium ion ATPase in P. falciparum, rapid and potent effect against all. Do not use alone to prevent resistance.
Often combined with lumefantrine

Question 17

Primiquine

Answer 17

“radicle Care” used to treat hepatic forms of P. vivax and P. Ovale. Unknown MOA. SEE HEMOLYTIC ANEMIA IN PTs With G6P deficiency.

Question 18

Doxycycline

Answer 18

Used for chloroquine resistant P. Vivax in combination with Quinine. binds 16S subunit of the ribosome to prevent translation.