Adverse effects to anti-malarial drugs are often unpredictable in incidence and intensity. Chloroquinine and mefloquinine have been known to cause neuropsychiatric reactions such as dizziness, sleep disturbances, anxiety and depression.

Dr. Jacquerioz and her co-investigator Dr. Ashley Croft with the Surgeon General’s Department in London reviewed eight trails including 4,240 participants to compare the effects of various prophylactic anti-malaria drugs in adult and child travelers.

"Atovaquone-proguanil and doxycycline are well tolerated by most travelers, and their profile of common neuropsychiatric adverse outcomes is better than that of mefloquine," said Dr. Jacquerioz. "However, the randomized controlled trials included in the review were not able to confirm or ease the concerns about mefloquine safety, such as serious neuropsychiatric adverse effect that threaten life, require or prolong hospitalization, or result in permanent disability.  Further research is needed to clarify this issue."

Drugs that are well-tolerated for malaria prevention should increase the likelihood of patient adherence and lead to better rates of prevention. Anti-malarial drugs are the best preventive measure for travelers to an endemic area. An estimated 10,000 to 30,000 travelers develop malaria each year, with about 150 dying from the disease.