It depends on the guidelines. If you're a pregnant woman or breastfeeding, it's probably the first line still, based on the CDC guidelines from a little while ago. So it gets down to these individual kinds of ideas. Of course, there's a lot of literature and a lot of concern about mefloquine right now. Say, we go to a patient or soldier who's going to a malaria endemic area, who sits down with a physician and asks him what he thinks because they need to pick something. If the soldier says, “Doc, I don't want that one I hear about on TV”, then we'll go somewhere else.
But there are other factors. Doxycycline is an antibiotic in the tetracycline class. If you have an allergy to that, that's out. If you have a G6PD abnormality, you take the other one out. There are reasons for using these drugs, and the ultimate reason should really be to prevent malaria in the safest way possible.