malaria
"I liked using the medicine as a prophylactic. I used it for a very long period of time. Four years or more with very few lapses at all. I just had to remember to take a daily pill and that was it. I took it for three trips in two years in a foreign country and three months before and after the trips. I took a six month, 11 month, and 9 month trip with only a six month and four month separation. I also took it during the lapses between trips since you should take it 90 days before the trip. I had no side effects during that period except that I did not get a cold very often. By the way, it was all at a high altitude since this was in Afghanistan."