Having had malaria is not a hindrance to holding a Class 1 medical. Nor is malaria quite the bad news that it used to be, however recently new strains have emerged that are more resistant to drugs.
As for preventive medicine, Lariam is a definite no-no. It has all kinds of unpleasant side effects. However pilots can use it as a cure, but donīt even think about flying until the effects have worn off completely (2-3 weeks). Expect some very unusual dreams.
Paludrine is the classic method, but you can only take it for six months, as long term use has various unpleasant effects on kidney and livers, etc.
A relatively new and seemingly very effective drug is Malarone. Is has no known side effects and can also be used to "cure" a case of malaria. It is however quite expensive, although not prohibitively so.
Sensible behaviour (long sleeve shirts, sleeping under mosquito nets, etc) goes a long way as well. I find that cooling my bedroom way down with airconditioning and then spraying with bugspray 30 minutes before I turn in usually kills mossies in the room and keeps the rest of the bastards out for the remainder of the night. They donīt like cold air, and given the choice will go somewhere else.
If you are only in a malaria area for less than 24 hours, it is usually not worth starting a treatment, but you can always get un-lucky.
Y'all have a nice day.