antimalarials Flashcards

1
Q

Chloroquine (ARALEN) and hydroxychloroquine (PLAQUENIL) MOA

A

“go-to drug”, for most sensitive forms
blood schizonticides, interferes with parasite’s feeding mechanisms, related to the drug’s ability to concentrate in and raise the pH of the parasite’s acidic food vacuoles
-clinical cure for all forms; radical cure for P. falciparum and P. malariae
-ppx if sensitive

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2
Q

Chloroquine (ARALEN) and hydroxychloroquine (PLAQUENIL) toxicity/SEs

A

CNS - dizziness, headache, tinnitus
GI upset - should be taken with food
retinal and corneal toxicity - monitor visual function in patients.
immunologic - skin rashes; blood dyscrasias; lupus - like symptoms; contraindicated in patients with psoriosis and porphyria.

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3
Q

Chloroquine (ARALEN) and hydroxychloroquine (PLAQUENIL)

A

Anti-inflammatory actions at high doses - Hydroxychloroquine (Plaquenil) is used in rheumatoid arthritis and lupus erythematosus.

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4
Q

Quinine and *Quinidine Gluconate MOA

A

acts on erythrocytic forms, (schizonticidal), older, for chloroquine-resistant P. falciparum
gametocytocidal (P. vivax and P. malariae)
MOA similar to chloroquine
-resistant P. falciparum

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5
Q

Quinine and *Quinidine Gluconate SEs

A

analgesia and antipyretic actions similar to aspirin
b. GI irritation, nausea, vomiting, etc..
c. blurred vision and auditory disturbances (tinnitus, deafness)
d. cardiovascular - quinidine-like depressant effect on heart
e. birth defects and abortion
f. skeletal muscle relaxation from mild neuromuscular blockade -used in low
doses for nocturnal leg cramps (e.g. Legatrim)
g. “Cinchonism” - syndrome of quinine toxicity that resembles salicylism
(headache, nausea, dizziness, blurred vision, tinnitus).

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6
Q

Mefloquine (LARIAM)

A

Acts on erythrocytic forms of the parasite (schizonticidal) like chloraquine
-for chloroquine-resistant and multidrug resistant
strains of P. falciparum

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7
Q

Mefloquine (LARIAM) SEs

A

can cause seizures and may aggrevate latent psychoses. It should not be used in patients with a history of mental illness or epilepsy.
Because of potential cardiac and CNS toxicities, the drug should be used with extreme caution in patients with CV disorders, psyciatric problems, or epilepsy

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8
Q

pyrimethamine (DARAPRIM) and proguanil (AKA chloroguanide) (PALUDRINE)

A

inhibits parasites’ dihydrofolate reductase, main effect is on erythrocytic forms.
sporozoite and pre-erythrocytic stages, and cryptomerozoites (secondary tissue forms).

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9
Q

pyrimethamine (DARAPRIM) and proguanil (AKA chloroguanide) (PALUDRINE) use

A

ppx, particularly for chloroquine resistant strains of P. falciparum

  • combo w. sulfa: pyimethamine plus sulfadoxine (Fansidar) for presumptive tx
  • lso used on conjunction with artemisinin analogs for treatment of chloroquine-resistant P. falciparum
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10
Q

Atovaquone + proguanil (Malarone)

A

newer

  • acts by depolarizing the parasite’s mitochondria and inhibiting electron transport
  • alternative to mefloquine or doxycycline for prophylaxis against chloroquine-resistant P. falciparium. It is fairly expensive and must be taken daily.
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11
Q

Primaquine

A
  • tissue forms* (exoerythrocytic) of all species of plasmodia
  • gametocytocidal
  • little effect on erythrocytic forms
  • not good ppx bc of fox
  • tried in combo w. clindamycin for PJP tx
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12
Q

Primaquine SEs

A

hemolytic anemia (esp. G6PD def. -may confer resistance to malaria)
teratogen
GI
CNS

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13
Q

doxycycline (and other tetracyclines)

A

antimalarial activity and are used as alternate or adjunctive drugs for the treatment and prophylaxis of malaria.

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14
Q

focus on the chart

A

at the end

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15
Q

P. falciparum

A

fever recurs every third day; no secondary tissue forms; drug resistant forms are becoming a serious problem.
-may be mixed infection w. P. vivax

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16
Q

P. vivax -

A

benign tertian malaria, most common form; fever every third day; secondary tissue forms; relapses; resistant strains are becoming more widespread.
P. ovale v. similar
-can be asymptomatic for months

17
Q

P. malariae

A

quartan malaria; fairly rare; fever every fourth day; no secondary tissue forms.

18
Q

life cycle

A

sporozoites from anopheles mosquito saliva–>enter the hepatic parenchymal cells (exoerythrocytic stage)–>ndergo asexual replication to be liberated as merozoites–>invade RBCs (erythrocytic stage) where they enlarge and multiply to form schizonts (schizogony)–>RBCs lyse–>releasing merozoites along with various metabolites and toxins which are responsible for the fever and chills–>free merozoites can infect more RBCs or differentiate into gametocyte (sexual forms)–>may be ingested by another mosquito where development into sporozoites continues, thus completing the cycle

19
Q

Blood schizonticides vs Tissue schizonticides

A

blood: suppress symptoms and provide a so called “clinical cure”, do not affect the secondary tissue forms of P. vivax and P. ovale
tissue: act on hepatic stages of the parasite, target P. vivax and P. ovale

Gametocytocidal agents - act on gametocytes; helps reduce spread

20
Q

w. P. vivax and P. ovale, some of the hepatic forms of the parasite can become dormant for ??

A

months -years (secondary tissue forms or “crypozoites”). This is why individuals who are infected with P. vivax or P. ovale can suffer relapses

21
Q

Causal prophylaxis

A

not practical; too many toxic effects, act on hepatic form

-primaquine, pyrimethamine and proguanil

22
Q

Suppressive Agents

A

act on erythrocytic forms to suppress symptoms

chloroquine

23
Q

artemether/lumefantrine (Coartem)

A
all forms including chloroquine-
resistant P. falciparum
-rapidly becoming primary drug of choice
-can be given IM
-used in combo
24
Q

artemisinin

A

blood schizonticide