CHLOROQUINE

One must be thorough with malarial parasite life cycle to understand about the chloroquine well . So i advice the readers to learn about the life cycle of plasmodium before reading this post.

CHLOROQUINE IS THE DRUG USED WIDELY FOR TREATING MALARIA . BEFORE WE SEE ABOUT THE DRUG IN DETAIL . LET'S REVIEW ABOUT THE DIFFERENT STAGES OF MALARIAL LIFE CYCLE AND THE SCHEMA OF TREATING MALARIA .

IN HUMANS MALARIAL PARASITE UNDERGOES 2 STAGES

1) PRE - ERYTHROCYTIC STAGE ( parasite is inside the liver ) 

2) ERYTHROCYTIC STAGE ( parasite is inside the RBC )

SCHEMA FOR TREATING MALARIA:

1. DRUGS TO TREAT THE ACUTE ATTACK : These drugs kill the plasmodium in the RBC .eg- chloroquine , mefloquine, artemisnin derivatives . 
2. DRUGS FOR RADICAL CURE :  For radical cure , combination of drugs that kill the erythrocytic stage + drugs that kill the exo-erythrocytic(liver) stage is used .
   eg- chloroquine + primaquine
3. DRUGS FOR PROPHYLAXIS : These drugs kill the plasmodium in the exo-erythrocytic(liver) stage.
   eg- primaquine , proguanil 
4. DRUGS FOR PREVENTING TRANSMISSION: These drugs kill the gametes . eg - chloroquine  

                                   CHLOROQUINE

MECHANISM :

                          Chloroquine accumulates in the food vacuole of PLASMODIUM ,  thus it is selective for erythrocytic stage of malaria ( food vacuole in the plasmodium is found only in the erythrocytic stage ). 

Then it inhibitis the conversion of heme to hemozoin .

Heme is toxic to the parasite , thus the parasite in the rbc gets killed.

OTHER ACTIONS of chloroquine:

1. Anti-inflammatory 
2. Anti-histamine
3. Anti-arrythmic
4. Local anesthetic 
5. Active against Giardia lamblia and Entamoeba histolytica

PHARMACOKINETICS :

1. Given orally 
2. Partly metabolized in liver
3. 70% excreted in urine unchanged
   30% excreted in urine as a metabolite .

USE:

1. R - Rheumatoid arthritis
2. E - Extra-intestinal amoebiasis
3. D- Discoid Lupus Erythromatosis
4. L - Lepra reaction
5. I - Infectious mononucleosis
6. P - Photogenic reaction
7. M - Malaria 
8. G - Giardiasis

   RED LIP Mahatma Gandhi is the mnemonic to remember the uses of chloroquine .

ADVERSE EFFECTS:

1. Skin rashes ( Lichenoid eruptions )
2. Peripheral neuropathy
3. Auditory impairment 
4. Blindness due to retinal damage ( bull's eye maculopathy)
5. Porphyria

BULL'S EYE MACULOPATHY