Chloroquine Phosphate

Category: Antimalarial drug
Form: Oral tablets

Uses:

• Treatment of malaria caused by Plasmodium species (P. vivax, P. ovale, P. malariae, and chloroquine-sensitive P. falciparum).

• Prevention of malaria in travelers to endemic areas.

• Occasionally used in autoimmune disorders like rheumatoid arthritis and lupus due to anti-inflammatory properties.

Mechanism of Action:

• Chloroquine accumulates in the parasite’s food vacuole inside red blood cells.

• Inhibits heme polymerization, causing accumulation of toxic heme that kills the malaria parasite.

• Also modulates the immune system, which accounts for its use in autoimmune diseases.

Administration:

• Taken orally, with or without food.

• Dosage depends on whether it is for treatment or prevention and on the patient’s age/weight.

• For malaria prevention, usually taken once weekly, starting 1–2 weeks before exposure and continued for 4 weeks after leaving the endemic area.

Side Effects:

• Common: nausea, vomiting, stomach upset, headache, dizziness.

• Other: itching (more common in dark-skinned individuals), mild skin rash, loss of appetite.

• Rare but serious:

  • Eye toxicity (retinopathy) with prolonged use

  • Heart rhythm disturbances (QT prolongation)

  • Severe allergic reactions

  • Blood disorders

Precautions:

• Avoid in patients with pre-existing retinal or visual abnormalities, severe liver or kidney disease.

• Long-term users should have regular eye exams.

• Use cautiously in patients with heart problems.

• Not recommended in pregnancy or breastfeeding unless prescribed by a doctor.

• Can interact with medications that affect heart rhythm or liver function.

Summary:
Chloroquine Phosphate is an oral antimalarial drug used to treat and prevent malaria and sometimes for autoimmune conditions. It works by disrupting the malaria parasite’s metabolism inside red blood cells. Common side effects include gastrointestinal upset, headache, and itching, while serious effects like retinopathy and heart rhythm disturbances are rare but require monitoring during prolonged use.