Mefloquine is a relatively new anti-malarial drug, developed in the mid-1980's by the Swiss pharmaceutical company Hoffman-LaRoche. It also goes by the trade names of "Lariam", "Mephaquine", and "Mefiam". It is used as both a prophylactic (preventative), and treatment for malaria.
Mefloquine is frequently prescribed to people travelling to areas of the world which are "High-Risk Malaria Zones", such as parts of Africa and Southeast Asia. The traveller will start taking it one week before leaving, once a week while there, continuing until 4 weeks after their return. If the traveller is unable to start one week in advance, their doctor may prescribe a heavier "loading dose" so that it will take effect sooner. Mefloquine has a half life of 3 weeks, so it will remain in your system for a long time.
Although mefloquine has a wide range of side effects, most people rarely experience them, and only approximately 1 in 150 people experience the more severe side effects. Most of mefloquine's side effects are related to the nervous system. From the Lariam product literature:
"The following unwanted effects have been reported to occur with 'Lariam': nausea, vomiting, dizziness, light-headedness or loss of balance, headache, sleepiness, inability to sleep, abnormal dreams, loose stools or diarrhea, and abdominal pain. In rarer cases, loss of appetite, abnormal heart beat, itching of the skin or skin rash, hair loss, eyesight problems, muscle pains, convulsions, and disturbances of mood (depressed mood, mental confusion, anxiety states) may occur."
Because many of these side effects are similar to symptoms of malaria, mefloquine toxicity is often mis-diagnosed as malaria.
I started taking Lariam yesterday in preparation for my trip to Nigeria. Although I'm not leaving until October 14th, I'm taking it early to make sure that I wont have a negative reaction to it. I dont want to be in Nigeria if I come down with mefloquine toxicity.