Antimalarial drugs

ANTIMALARIAL DRUGS

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ANTIMALARIAL DRUGS :

MALARIA

Malaria is a protozoan infection .It is caused by 4 species:

Species causing malaria

Plasmodium vivax benign Plasmodium ovale Plasmodium falciparum

malignant Plasmodium malaria. Benign

tertian.

TRANSMISSION OF MALARIA

BITE OF FEMALE ANOPHELES MOSQUITO

SHARING NEEDLES

BLOOD TRANSFUSION

LIFE CYCLE AND SITES OF DRUG ACTIONS:

CHLOROQUINE

It is a 4- aminoquinoline

It is a rapidly acting erythrocytic schzonticide against all species of plasmodium.

Controls most clinical attacks in 1-2 days with disappearance of parasites from peripheral blood in 1-3 days.

Mechanism of action

It is a basic drug, which is taken by acidic food vacuoles of susceptible plasmodia and inhibits conversion of haeme to haemozoin.

Mechanism of action

chloroquine

concentrated in acidic vacuole of parasite

binds to haeme drug

haeme complex damages

plasmodia membrane

pharmacokinetics

Oral absorption is excellent .absorption after i.m inj is also good

About 50% is bound to plasma

High affinity for melanin and nuclear chromatin : gets tightly bound to these tissue constituents and is concentrated in liver ,spleen,kidney,lungs,skin,leucocytes and some other tissues.

Its selective accumulation in retina is responsible for ocular toxicity seen with prolonged usage. +

Partly metabolised in liver and excreted in urine.

Early plasma half life is 3-10 days.because of tight tissue binding, small amounts persist in body with a terminal half life of 1-2 months.