.... particularly if scuba is involved.
From his post above: "There are lots of horror stories about Lariam, mostly exaggeration. The majority of people (and especially children, who haven't heard the stories) tolerate it quite well."
Here is an unedited version of a piece from my "Ask RSD" column in the Nov '99 issue of "Rodale's Scuba Diving":
"Lariam (mefloquine) is a very effective drug in preventing and treating malaria, but can give rise to unwanted side effects, including vivid & disquieting dreams, hallucinations, anxiety, depression, confusion and forgetfulness. The US package insert directs that "...caution should be exercised with regard to driving, piloting an airplane, and operating machinery as dizziness, a disturbed sense of balance, neurological or psychiatric reaction have been reported during and following the use of Lariam," and states that "dizziness, sensory & motor abnormalities, headache and fatigue have been recorded in patient's taking the drug."
These cautions are consistent with suggestions by some in the medical and dive communities that mefloquine may produce side effects which mimic DCS.
Of most concern to the diver are the positions of some medical professionals that the drug simply should not be taken for malaria prophylaxis by those who are actively diving. These sources include Rodale's Diving Doc," Dr. Samuel Shelanski, and the German Society for Tropical Diseases. This later group, whose policies can be used as a basis for professional and legal action in cases of harm resulting from a physician's failure to follow them, states that people with a special need for three-dimensional orientation, for example pilots, scuba divers and others, should not take mefloquine as prophylaxis. Similar advice regarding scuba diving is provided by Dr Bridget Farham, B.Sc (hons), Ph.D, MB.ChB., an expert on tropical medicines, and appears in the package insert accompanying mefloquine dispensed in South Africa.
The above information suggests it would be prudent to take this drug only after detailed discussion with a physician who is fully aware of its current status, and to closely monitor for any adverse reaction."
Since I wrote this, our FDA has gone so far as to write a special guide for it's use---->
http://www.fda.gov/bbs/topics/NEWS/2003/NEW00921.html
Finally, I have run across dive ops in the Australasia region that will not let you dive if you indicate that you are taking Lariam.
Obviously, there is much to be considered before using mefloquine, especially during a diving vacation.
DocVikingo