Chloroquine ( CQ) Uses, Side Effects, and More

 Chloroquine(CQ) 

Brand name:- Resochin, cloquin, lariago,Nivaquin-p 250mg tab.

Chloroquine is an antiparasitic medication that treats malaria. It works by increasing the levels of haeme in the blood, a substance toxic to the malarial parasite. This kills the parasite and stops the infection from spreading.

Pharmacodynamic:- 

Chloroquine inhibits the action of heme polymerase, which causes the buildup of toxic heme in Plasmodium species. It has a long duration of action as the half life is 20-60 days.10 Patients should be counselled regarding the risk of retinopathy with long term usage or high dosage, muscle weakness, and toxicity in children.

Pharmacokinetics:- 

Oral absorption of CQ is excellent. About 50% gets bound in the plasma. It has high affinity for melanin and nuclear chromatic: gets tightly bound to these tissue constituents and is concentrated in liver , spleen, kidney,lungs (several hundred -fold), skin , leucocytes and some other tissues. It's selective accumulation in retina is responsible for the ocular toxicity seen with prolonged Use.

Chloroquine is partly metabolized by liver and slowly excreted in urine. The early plasma t½ varies from 3-10 days . Because of tight tissue binding, small amounts persist in the body with a terminal t½ of 1-2 months.

Mechanics of action:-  

The quinolines mostly exert their antimalarial effect during the blood stages or liver stages of the life cycle of the parasite . As a protonated, weakly basic drug, CQ increases pH and accumulates in the food vacuole of parasites, where the host erythrocyte hemoglobin degrades, leading to the release of the toxic products. Iron (II) protoporphyrin IX (FeIIPPIX) is automatically oxidized to toxic iron (III) protoporphyrin IX (FeIIIPPIX) or hematin, but the parasites can survive by detoxifying hematin to a dimerized nontoxic hemozoin form. CQ inhibits the polymerization and detoxification of hematin and interferes with the degradation of host erythrocyte hemoglobin, preventing Plasmodium growth . Therefore, CQ causes the accumulation of free hematin that is highly toxic to Plasmodium, resulting in dissolution of the cell membrane and, ultimately, death of the parasites.

Moreover, the peroxidation of parasite lipid membranes, inhibition of lactate dehydrogenase and tyrosine kinase, oxidation of proteins, and damage to DNA also have important roles in the viability of the parasites . CQ can insert into the DNA double helix structure of Plasmodium to form a stable DNA-CQ complex. This complex affects DNA replication and RNA transcription, thus inhibiting Plasmodium growth and reproduction . However, the exact antimalarial mechanisms involved remain controversial.

used:- 

used to prevent or treat malaria caused by mosquito bites. Chloroquine belongs to a class of drugs known as antimalarials.

side effects:-

Nausea, vomiting, abdominal cramps, headache, and diarrhea may occur.

 Dose:- As Directed by your doctor.