Mefloquine (brand name Lariam®) is a prescription medication used in the prevention or treatment of some types of malaria, a life-threatening illness spread by mosquitoes. This drug, which is also known as mefloquine hydrochloride, belongs to the class of medications known as antimalarial agents that includes five other medicines commonly used in malaria treatment or prevention. Its use as a chemical prophylactic decreases the risk of malaria infection but is not a guaranteed block to transmission of the disease. Mefloquine is not recommended for certain types of individuals, including pregnant or breastfeeding women, people with a history of psychiatric disorders, and those who might be prone to seizures.
With a long half-life in the body, this drug is generally taken once a week and could still exist in trace amounts in the bloodstream months later. The majority of the drug is usually excreted through feces and bile within 15 to 33 days of ingestion. For individuals who will be traveling in areas of the world where malaria infection is possible, doctors typically recommend beginning the course of mefloquine between one and three weeks before travel. This allows the antimalarial agent to accumulate in the bloodstream before potential exposure to malarial mosquitoes, and it also provides an opportunity to discover any serious side effects before beginning travel.
Mefloquine and other antimalarial agents are believed to reduce the likelihood of contracting malaria from an infected mosquito, but their use does not guarantee full protection. Individuals who travel to areas with malarial mosquitoes are encouraged to take additional precautions, such as using effective mosquito repellent, wearing long sleeves and pants, and using a bed net between dusk and dawn when mosquitoes are most active. Travelers should also have a plan for the procurement of alternative antimalarial drugs in the event that they develop serious reactions to mefloquine. Some of the more serious potential side effects can include seizures, uncontrollable shaking, depression, tingling in the fingers or toes, and hallucinations or other psychotic symptoms. There is also a chance of damage to the eyes or liver when taking mefloquine long-term.
Approximately 1 million people die from malaria annually. Symptoms often include fever and indications of an influenza-like infection, such as headache or chills. Malaria symptoms might develop within two weeks of exposure but can also manifest months later. Individuals who have had malaria in the past are not protected from contracting the disease again.