Malaria Prevention: Lariam, Malarone, and what to do

 Stuart G. Garrett, MD · Bend Memorial Clinic

Malaria can be a fatal disease. If you don't die, it can cause long-term disability. It is sometimes hard and costly to treat. It is usually preventable in travelers with proper precautions. There are four types of malaria worldwide. There is no vaccine yet. Medications that prevent malaria are expensive, they have side effects, and are not 100% effective. The dilemma travelers face is how to balance the risk of getting malaria with the benefits and risks of measures to prevent it. Obviously, simple measures such as proper clothing, bed nets, repellents, and avoiding malarious areas and times are relatively cheap and easy and essential to do (see cdc.gov website, very good for prevention ideas). Taking medications to prevent malaria adds expense and risk, but also provides higher levels of protection. A number of medications are effective in preventing malaria. The use of an antimalarial regimen should involve balancing the potential adverse effects against the risk of acquiring malaria. 

LARIUM (mefloquine)

Mefloquine (Lariam) is the drug of choice for most travelers to chloroquine-resistant regions.  The traveler takes one 250-mg tablet once per week for two weeks before departure, one tablet per week during travel, and one tablet per week for four weeks after returning home. Significant side effects seem to occur about 0.5% of the time. Seizures are reported in 1/1100 and hospitalization in 1/650. Most side effects occur by the third dose, so if you take it 21/2[.1]  weeks prior to departure, you should know how you will respond. Alcohol consumption seems to increase the incidence of side effects. Scuba divers may want to be sure they tolerate it in order to avoid underwater reactions. Persons with seizures, mood disorders, depression, liver problems, pregnancy, or breast-feeding shouldn't take Lariam. Caution is urged if you have psychiatric illness. In the past decade, reports of neuropsychological adverse effects have raised concerns about this drug. However, adverse effects are similar in frequency and severity to those reported with weekly chloroquine use. The most commonly reported side effects include nausea, dizziness, headaches, and vivid dreams. Mefloquine should be used with caution in patients with a history of psychosis, seizure disorder, or cardiac conduction defects. It is the safest option for the prevention of malaria in pregnant women traveling to areas with chloroquine-resistant P. falciparum.

 MALARONE (atovaquone/proquanil))

In 2000, the U.S. Food and Drug Administration approved a fixed-combination tablet of atovaquone and proguanil (Malarone) for the prevention of malaria. Travelers need only take the medication during periods of exposure and for one week after departure from the malarial region. This regimen has an advantage over that of mefloquine and doxycycline, which have to be taken for four weeks following exposure. Atovaquone/proguanil has been found to be useful against strains of malaria that are resistant to other agents. The adult dosing regimen for prevention consists of one tablet (250 mg atovaquone/100 mg proguanil) per day starting two days before travel, one tablet per day during travel, and one tablet per day for seven days after leaving an endemic area. The most common adverse effects are abdominal pain, nausea, and headaches. Because of insufficient data on its safety, pregnant or lactating women should not take it. Atovaquone/proguanil also is contraindicated in persons with severe renal impairment. This drug combination generally is well tolerated and effective in the prevention of P. falciparum infection. Expensive ($6.20 per tablet!) Coverage for a 10-day trip costs $115.

 CHLOROQUINE

Because of the emergence of drug-resistant P. falciparum strains, chloroquine (Aralen) is no longer the recommended preventative medication in most parts of the world. Chloroquine is still recommended for prevention in travelers to Central America west of the Panama Canal, Hispaniola (Haiti and the Dominican Republic), Argentina, parts of China, and parts of the Middle East (primarily Syria, Jordan, and Iraq).

The antimalarial dosage for a traveler to these areas is one 500-mg tablet (300 mg base) per week beginning two weeks before departure, with one tablet per week during exposure, and one tablet per week for four weeks after the trip. The most common side effect is heartburn, but chloroquine also can cause itching (especially in dark-skinned persons), exacerbations of psoriasis, agranulocytosis, photosensitivity and, rarely, neuropsychiatric disturbances such as vertigo or insomnia. The drug is a safe option during pregnancy. Inexpensive.

 DOXYCYCLINE (tetracycline)

Doxycycline (Vibramycin), a tetracycline, continues to be the preferred agent for persons unable to tolerate mefloquine and for those traveling to areas where mefloquine resistance is present. The drug is taken in a dosage of 100 mg daily during exposure and continued for four weeks after the traveler returns home. No loading dose is required. Doxycycline has been shown to have prophylactic efficacy comparable to mefloquine, but the need for daily dosing may reduce adherence and, therefore, effectiveness. Side effects of doxycycline include heartburn, vaginitis, abdominal pain, diarrhea, and skin problems. It can't be taken by pregnant or women or kids under 12 or those allergic to tetracycline. Because the drug can be photosensitizing (3%), its use requires adequate sunscreen protection. Doxycycline is contraindicated in pregnant or breastfeeding women and in children younger than eight years. Long-term administration of tetracyclines generally has been well tolerated. Mefloquine should be used with caution in patients with a history of psychosis, seizure disorder, or cardiac conduction defects. It is the safest option for the prevention of malaria in pregnant women traveling to areas with chloroquine-resistant P. falciparum. Inexpensive.

 Other options: 

Medications commonly used in the UK are not available in the US and are less effective (70% vs. 90%). Carrying treatment and treating if you get a high fever is too risky and you may be treating the wrong ailment. Self-diagnostic kits are on the market, but are only good for one of the 4 types of malaria.

 Web sites:
CDC Travelers' Health Information: www.cdc.gov/travel
World Health Organization International Travel and Health: www.who.int/ith
International Society of Travel Medicine: www.istm.org
American Society of Tropical Medicine and Hygiene: www.astmh.org
Pan American Health Organization: www.paho.org
Malaria Foundation International: www.malaria.org