Chloroquine is the medication of choice in the following malarious areas:
- Central America west of the Panama Canal Zone.
- Mexico (Mainly in forested Yucatan Peninsula)
- Dominican Republic: Mainly along Haitian border. Occasional outbreak in tourist areas.
- Most of the Middle East (chloroquine resistance has been reported in Yemen, Oman and Iran).
- All other areas of the world exhibit chloroquine resistance and other medications should be used to prevent malaria.
Chloroquine comes in the following forms:
- Chloroquine phosphate (Aralen): 250 or 500 mg salt/tablet = 150 or 300 mg base/tablet.
- Hydroxychloroquine sulfate (Plaquenil): 200 mg salt/tablet = 155 mg base/tablet.
- Adults: 500 mg chloroquine phosphate (300 mg base) once/week with food.
- Children: 5 mg/kg base (maximum 300 mg base) once/week with food.
Begin one week before travel to a malaria region and continuing weekly for duration of stay and for four weeks after leaving malaria region.
- Stomach upset with vomiting. Can be minimized by taking the medication with food.
- Rarely it can make psoriasis, eczema worse.
- Headache, confusion, depigmentation of hair, skin eruptions, Clouding of cornea, weight loss, partial hair loss, muscle pains, sensitivity to light are all known rare side effects.
- Rare: irreversible retinal injury (especially when total dosage exceeds 100 grams in a life time). Persons on chronic chloroquine should have their eyes examined by an ophthalmologist every year while they are on the medication.
Chloroquine appears to be safe for use in all trimesters of pregnancy.
Interaction with Other Drugs
- Acetaminophen (Tylenol, and others): may cause chloroquine toxicity
- Cimetidine (Tagamet): Decreases metabolism of chloroquine and may cause toxicity
- Chlorpromazine: Possible chlorpromazine toxicity due to decreased metabolism
- Cyclosporine: Possible cyclosporine toxicity due to decreased metabolism
- Kaolin or Kaolin-pectin: Possible decreased chloroquine effect due to decreased absorption
- Methotrexate used for rheumatoid arthritis: Possible decreased methotrexate effect due to decreased absorption
- Metronidazole (Flagyl): Abnormal stiffness
- Praziquantel (Biltricide): Possible decreased praziquantel effect
- Promethazine : Possible chloroquine toxicity
- Rabies Vaccine: Decreased antibody response to human rabies vaccine when the intradermal route is used instead of the intramuscular route.