This was reported in February 1995 in the journal of the Canadian Medical Association. It's a report that would have been read by all Canadian doctors, including military doctors.
It was a case where two buddies were in a tent. One of them was taking mefloquine and the other was taking nothing, because he was a tough guy. They were prospecting for rocks in Tanzania. The guy taking mefloquine took it every Sunday, and everything was going fine. He was getting no side effects.
Then one day, three weeks into the trip, they shared a bottle of whisky on a Saturday night. The effect of that was to make the one who was taking the mefloquine psychotic, while the other one experienced nothing. He started getting auditory and visual hallucinations and was convinced his buddy was going to murder him, so he was going to murder him in exchange, but he controlled himself.
The next day he got very depressed for a day, and then he recovered. He felt a bit strange but by Tuesday he was all right, so everything was fine during the week.
The following weekend—this is all in the paper, by the way; these were Canadian geologists—exactly the same thing happened. They shared a bottle of whisky. The one taking mefloquine became psychotic and had hallucinations, was convinced his buddy was trying to murder him, and wanted to murder him in exchange. The next day, he took his mefloquine tablet and went into deep depression for a day, and by Tuesday was all right.
He decided it had to be the interaction between the mefloquine and alcohol. He decided to stop drinking whisky at the weekend and the rest of the trip he was fine. He came back to Canada and was seen at the Ottawa Civic Hospital. They said this looks like a serious interaction with intense alcohol exposure. They published the report, and of course, that didn't go down at all well with the drug company, because they didn't want a drug that was meant for tourists to have a precaution against alcohol with it.
They set up their own—what I call bogus—alcohol study, which they published the following year, which they carried out to discredit this very important, and in my view, very persuasive Canadian report. In the Dutch study, they got a population of 40 very healthy young people who were more or less teetotallers. They gave them a thimbleful of alcohol— 50 grams—in orange juice, over two hours. Some of them were taking mefloquine and some weren't, but they hadn't taken any mefloquine for a day. Then they put them out on the road and made them drive around and do some other tests and they published it as showing there was no effect of alcohol and mefloquine at all, at least not at low doses.
By that strategy, Roche were able to discredit this very important, in my view, hazard to taking mefloquine. It is one that the troops will inevitably face because that's the way soldiers drink. They don't drink moderately. They drink heavily once a week and if it happens to coincide with the day they take mefloquine, it seems to be a great risk, based on this Canadian study.
During my 20 years in the army I saw it again and again. It was very often the influence of taking alcohol at the same time as mefloquine that made soldiers act irrationally and completely out of character.
After some time, I persuaded to have a policy change in the British Army, which was introduced in December 2005. A policy letter came out: Soldiers taking mefloquine were not to take alcohol; female soldiers were not to take the oral contraceptive pill—it seems to have the same kind of effect— and they were not to take other prescription drugs.
That seemed to mitigate the risk. After that date we observed many fewer episodes of mefloquine-related events, if I may call them that.