Flying in Sierra Leone last year, was advised by the local doc just to take sensible precautions with bug spray, mosie nets etc. Malarone won't stop you contracting Malaria, and upon any symptoms, his first action would be to give me Malarone anyway. Had no problems at all.
I have to add that, the year before, I was in Mali with wife. We started Malarone prior to going and after about 3 days in country I came down with terminal screaming ab-dabs. That night as wife gave me my Malarone, I noted that they no longer had "Malarone" inscribed..........yep, she was giving me the wrong pills ffs! I did note that she was not affected by taking the laxatives she was feeding us???? or at least, feeding me!
Tam