What are the recommended medications for malaria prophylaxis?

Recommended Medications for Malaria Prophylaxis

The recommended medications for malaria prophylaxis include chloroquine, mefloquine, doxycycline, and atovaquone-proguanil, with the choice depending primarily on the region of travel and the presence of drug-resistant Plasmodium strains. 1, 2, 3

Regional Considerations for Prophylaxis

Chloroquine-Sensitive Areas

• Chloroquine (300 mg base weekly) remains the first-line prophylactic medication for travel to areas without chloroquine-resistant P. falciparum, such as parts of Central America west of the Panama Canal 3
• Chloroquine should be started 1-2 weeks before travel, continued during travel, and for 4 weeks after leaving the malarious area 3, 4
• For those who cannot tolerate chloroquine, hydroxychloroquine may be a better-tolerated alternative 3

Areas with Limited to Moderate Chloroquine Resistance

• Chloroquine (300 mg base weekly) combined with proguanil (200 mg daily) provides substantial protection in areas with limited to moderate chloroquine resistance 1
• This combination has fewer neuropsychiatric side effects than mefloquine but may cause mouth ulcers, gastrointestinal upset, and skin eruptions 1

Areas with High Chloroquine Resistance

• Mefloquine is recommended for areas with high risk of chloroquine-resistant falciparum malaria 1, 5
• For adults, the dosage is one 250 mg tablet weekly, starting 1 week before arrival in the endemic area and continuing for 4 weeks after leaving 5
• Doxycycline is a first-line alternative in areas with mefloquine-resistant falciparum malaria, particularly in East Asia 2
• Atovaquone-proguanil is effective against drug-resistant strains of P. falciparum and has fewer side effects than other regimens 6, 7

Specific Antimalarial Medications

Mefloquine

• Effective against chloroquine-resistant P. falciparum but associated with neuropsychiatric side effects 1, 5
• Contraindicated in those with history of convulsions, epilepsy, or serious psychiatric disorders 1
• Pediatric dosage is weight-based: 20-25 mg/kg for treatment 5
• Not suitable for those with liver impairment 1

Doxycycline

• Recommended as an alternative regimen for travelers to areas with chloroquine-resistant P. falciparum 2
• Particularly useful in areas with mefloquine resistance 2
• Not recommended for children under 8 years, pregnant women, or lactating mothers 2, 8
• Side effects include photosensitization; excessive sun exposure should be avoided 2, 8
• Drug interactions with phenytoin, carbamazepine, and barbiturates may shorten its half-life 2, 8

Chloroquine

• Standard dose is 300 mg base weekly for prophylaxis 1, 4
• May cause hemolysis in glucose-6-phosphate dehydrogenase (G-6-PD) deficiency 4
• Should be used with caution in patients with hepatic disease or alcoholism 4
• May increase the risk of convulsions in patients with a history of epilepsy 4

Atovaquone-Proguanil

• Highly effective against drug-resistant strains of P. falciparum 6, 9
• Both components are active against hepatic stages of P. falciparum, allowing for shorter post-travel prophylaxis (7 days) 6, 10
• Generally well tolerated with fewer gastrointestinal adverse events than chloroquine plus proguanil, and fewer neuropsychiatric adverse events than mefloquine 6, 11

Important Considerations for Prophylaxis

Compliance and Timing

• Compliance is essential; most malaria deaths occur in travelers who do not fully comply with prophylaxis regimens 1, 2
• Start prophylaxis 1-2 weeks before travel (except atovaquone-proguanil which can be started 1-2 days before) 1, 2, 6
• Continue prophylaxis for 4 weeks after leaving the malarious area (except atovaquone-proguanil which can be stopped 7 days after leaving) 1, 10

Additional Protective Measures

• Use insect repellents containing DEET on exposed skin 2
• Wear long-sleeved clothing and long trousers if outdoors after sunset 1, 2
• Use pyrethrum-containing flying-insect spray in living and sleeping areas 2
• Consider permethrin-treated clothing and mosquito nets for additional protection 2

Special Populations

• Pregnant women should avoid travel to malaria-endemic areas if possible; if travel is necessary, consult a travel medicine specialist 3
• Children's dosages are weight-based; mefloquine and doxycycline have specific age restrictions 5, 8
• Patients with renal or hepatic impairment may require dosage adjustments or alternative medications 4

Common Pitfalls and Caveats

• No prophylactic regimen guarantees 100% protection against malaria 3
• P. vivax and P. ovale can cause relapsing malaria due to persistent liver stages (hypnozoites) that can remain dormant for up to 4 years 12
• Symptoms of malaria can develop as early as 8 days after exposure or as late as several months after leaving the malarious area 3
• Prompt medical evaluation is essential if symptoms develop, as delayed treatment can have serious or fatal consequences 3, 7
• Malaria prophylaxis should be selected based on the specific travel destination, duration of stay, and individual patient factors 1, 2, 3