Ask the CAA about what is acceptable. I took mefloquine for 5 months with no ill effects.
Also, the most important thing is to realise that the best protection against mossies is to avoid getting bitten -- cover up at dawn and dusk, repellent and medicated bed net. The next most important thing is to seek medical advice immediately if you get a fever in the tropics, irrespective of whether you're on prophylaxis or not. If you're in a very remote place and get a fever, start treatment for malaria immediately on spec.
QDM