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 conditions such as rheumatoid arthritis and systemic lupus erythematosus due to anti-inflammatory properties.

Mechanism of Action:

• Chloroquine accumulates in the food vacuole of the malaria parasite within red blood cells.

• It inhibits heme polymerization, causing a buildup of toxic heme, which kills the parasite.

• Its immunomodulatory effects help reduce inflammation in autoimmune diseases.

Administration:

• Taken orally, with or without food.

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

• For malaria prevention, it is 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, abdominal discomfort, headache, dizziness.

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

• Rare but serious:

  • Retinopathy or vision problems with long-term use

  • Heart rhythm disturbances (QT prolongation)

  • Severe allergic reactions

  • Blood disorders

Precautions:

• Avoid in patients with pre-existing eye disease, liver or kidney impairment.

• Long-term use requires regular eye exams.

• Use cautiously in patients with heart conditions.

• Not recommended during pregnancy or breastfeeding unless prescribed.

• Monitor for potential interactions with other drugs that affect heart rhythm.

Summary:
Chloroquine Phosphate is an oral antimalarial and immunomodulatory drug used to treat and prevent malaria and manage certain 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 rare serious effects such as retinopathy and heart problems require monitoring, especially during long-term use.