Malaria Prophylaxis Recommendations
The choice of malaria prophylaxis depends entirely on whether you are traveling to an area with chloroquine-resistant P. falciparum—use chloroquine 300 mg base weekly for chloroquine-sensitive areas, or atovaquone-proguanil, doxycycline, or mefloquine for chloroquine-resistant regions.
Risk Assessment and Drug Selection Algorithm
The first critical step is determining the resistance pattern in your destination:
For chloroquine-sensitive areas (Central America west of Panama Canal, Haiti, parts of Middle East): Use chloroquine 300 mg base (500 mg chloroquine phosphate) once weekly 1, 2, 3
For chloroquine-resistant areas (most of Africa, Southeast Asia, South America): Choose from three first-line options based on patient factors 1, 2, 4:
- Atovaquone-proguanil (preferred for short trips, best tolerability)
- Doxycycline 100 mg daily (alternative for mefloquine-resistant areas, contraindicated in pregnancy and children <8 years) 1, 5
- Mefloquine 250 mg weekly (effective but neuropsychiatric side effects in 0.01%-higher; avoid in those with seizure history, psychiatric disorders, or need for precision movements) 1, 2
Timing and Duration
Critical timing varies by medication and starting early allows assessment of side effects before departure 1:
- Chloroquine/mefloquine: Start 1-2 weeks before travel, continue weekly during travel, and for 4 weeks after leaving the malarious area 1, 3
- Doxycycline: Start 1-2 days before travel, continue daily during travel, and for 4 weeks after departure 1, 5
- Atovaquone-proguanil: Can start 1-2 days before travel and continue for only 7 days after leaving (though emerging evidence suggests even 1 day post-exposure may suffice) 2, 6
Special Populations
Pregnant women and young children require specific considerations 1:
- Pregnant women: Chloroquine is the safest option; carry Fansidar for presumptive self-treatment if fever develops and medical care unavailable 1
- Children <15 kg: Chloroquine preferred; mefloquine and doxycycline contraindicated 1
- Children >8 years: Doxycycline 2 mg/kg daily (up to adult dose) is acceptable 5
Critical Pitfalls to Avoid
Most malaria deaths in U.S. travelers occur due to non-adherence—among U.S. residents with malaria in 2018,95% did not adhere to or did not take recommended chemoprophylaxis 7:
- Never stop prophylaxis early: Continue for full 4 weeks post-exposure (except atovaquone-proguanil at 7 days) even if you feel well 1, 2
- Chloroquine side effects: Take with meals or split into twice-weekly doses if gastrointestinal upset occurs; hydroxychloroquine may be better tolerated 1, 8
- Mefloquine neuropsychiatric effects: Occur in first three doses (70% of cases); discontinue immediately if severe mood changes, hallucinations, or seizures develop 1
- Doxycycline photosensitivity: Avoid excessive sun exposure; can be severe and prolonged 1
Relapsing Malaria Prevention
For P. vivax and P. ovale exposure, liver stages can cause relapses up to 4 years later 1, 8:
- Primaquine 30 mg base daily should be given during the last 2 weeks of the 4-week post-exposure prophylaxis period to prevent relapses 1, 8, 9
- Mandatory G6PD testing before primaquine use; contraindicated in pregnancy 8, 9
- Primaquine offers 85-93% protective efficacy and causes only mild, transient methemoglobinemia (<13%, typically <6%) 9
Personal Protection Measures
No chemoprophylaxis provides 100% protection—combine with mosquito avoidance 2, 8, 3:
- Remain in well-screened areas between dusk and dawn when Anopheles mosquitoes feed 3
- Use DEET-containing repellents on exposed skin 2, 3
- Wear long sleeves and pants after sunset 2, 3
- Sleep under permethrin-treated bed nets 3
- Apply permethrin spray to clothing for additional protection 1, 3
When Prophylaxis Fails
Seek immediate medical evaluation if fever develops during or within 1 year after travel 2, 3:
- Malaria symptoms can appear 8 days to several months post-exposure 3
- Delayed treatment can be fatal—mortality is 0.3% in the U.S. but preventable with prompt diagnosis 4
- Severe malaria (14% of U.S. cases) requires IV artesunate, now FDA-approved and commercially available 4, 7
- For urgent consultation, call CDC Malaria Hotline at 770-488-7788 (business hours) or 770-488-7100 (after hours) 7