I wonder where you on chloroquine — that sounds more like the side effect profile. Hyrdoxycholorquine has very few side effects according to the people for whom I have given the drug. I have no experience with chloroquine, but I am under the impression that it was a rougher drug in terms of side effects.
The military had moved to hydroxychloroquine by the end of the Carter administration, but the dosage was much higher than today’s civilian dosage.
Hydroxychloroquine has a half life of forty to sixty days. After two weeks at 400mg it’s effective for malaria for maybe forty days if you stop, but much longer if you keep taking 400mg per week.
A Marine line battalion on a little island in the Philippines might not be able to dose its personnel for a three month stretch. That requires filling up the troops till they almost puke.
I think logistics is much better now, so it’s unlikely that they still use such heavy doses.
Probably someone still in will read this thread and give a current update if the thread doesn’t get buried.
VietNam malaria pill was Acloriquine-primaquine-phosphate.