Chloroquine Regimen for Malaria
For chloroquine-sensitive malaria, use chloroquine 1,500 mg total dose over 3 days: 600 mg at 0 hours, 600 mg at 24 hours, and 300 mg at 48 hours for adults; for children, give 25 mg/kg total dose split as 10 mg/kg, 10 mg/kg, and 5 mg/kg at the same intervals. 1, 2
Treatment Dosing Regimens
Adults
- Day 1: 600 mg base (1,000 mg salt) initially, then 300 mg base (500 mg salt) 6-8 hours later
- Days 2-3: 300 mg base (500 mg salt) once daily
- Total dose: 1,500 mg base (2,500 mg salt) over 3 days 1, 2
Children
- Total dose: 25 mg base/kg over 3 days
- Schedule: 10 mg/kg at 0 hours, 10 mg/kg at 24 hours, 5 mg/kg at 48 hours 1, 2
- Critical: Never exceed adult dose regardless of child's weight
Pregnant Women
Treat aggressively using the adult regimen—chloroquine is safe during all trimesters of pregnancy. 1 This is essential as malaria in pregnancy carries high morbidity and mortality risks.
Prophylaxis Dosing
Standard Prophylaxis (Chloroquine-Sensitive Areas)
- Adults: 300 mg base (500 mg salt) once weekly on the same day 3, 2
- Children: 5 mg base/kg once weekly (never exceeding adult dose) 2
- Timing: Begin 1-2 weeks before travel, continue weekly during exposure, and for 4 weeks after leaving the malarious area 3, 2
Loading Dose Option
If unable to start 2 weeks early, give double initial dose: 600 mg base for adults or 10 mg base/kg for children, split into two doses 6 hours apart 2
Critical Contraindications
Absolute contraindications 2:
- Known hypersensitivity to 4-aminoquinoline compounds
- Pre-existing retinal or visual field changes (for chronic use beyond acute malaria)
Relative cautions:
- G6PD deficiency (relevant when adding primaquine for P. vivax/ovale)
- Psoriasis (may be exacerbated) 3
- Prolonged use >6 years cumulative requires periodic ophthalmologic exams 3
Species-Specific Considerations
P. vivax and P. ovale
After completing chloroquine treatment, add primaquine for radical cure to eliminate liver hypnozoites 1:
- Adults: 15 mg base daily for 14 days
- Children: 0.3 mg/kg/day for 14 days
Critical G6PD warning: In populations with severe G6PD deficiency (notably Asians), primaquine should not exceed 5 days due to life-threatening hemolysis risk. Test for G6PD deficiency before primaquine whenever possible. 1
Chloroquine-Resistant P. falciparum
Do not use chloroquine monotherapy. Switch to artemisinin-based combination therapy (artemether-lumefantrine preferred) or alternative regimens 4, 5. If chloroquine is started empirically and patient remains symptomatic after 48-72 hours, immediately switch to second-line drugs 1.
Monitoring and Follow-Up
Treatment Monitoring
- If symptoms persist >3 days, repeat thick blood smear 1
- If parasitemia hasn't markedly decreased by day 3, institute alternative therapy immediately 1
- Common pitfall: Assuming fever is always malaria—rule out pneumonia, meningitis, and other causes even with positive smears 1
Administration Tips
- First dose can be given when blood smear is obtained (don't wait for results) 1
- If supervised 3-day therapy impossible, give first dose supervised and provide remaining doses with instructions 1
- Can be administered via nasogastric tube in comatose patients (well absorbed) 6
Safety Profile
Minor side effects (common but rarely require discontinuation) 3:
- Gastrointestinal disturbance
- Headache, dizziness
- Blurred vision
- Pruritus
Serious adverse effects (rare at prophylactic/treatment doses):
- Retinopathy (only with chronic high-dose use, not standard malaria dosing) 3
- Cardiovascular effects (hypotension with rapid IV/IM administration—avoid bolus dosing) 6
Drug interaction: Chloroquine may interfere with intradermal rabies vaccine antibody response 3
Geographic Applicability
Chloroquine remains effective only in limited areas 5:
- Haiti (only area in Western Hemisphere)
- Limited parts of Central America
- Some Middle Eastern countries
- Most of sub-Saharan Africa and Southeast Asia have widespread resistance
Always verify current resistance patterns before prescribing chloroquine for prophylaxis or treatment. The default assumption should be resistance unless proven otherwise in 2024.