We are in our 70s and will be on a cruise from Siem Reap to Ho Chi Minh. Which anti malarial would be most effective for these areas?
The main thing to consider when travelling to south-east Asia is that there are areas where some of the malaria is resistant to mefloquine (commonly sold as Lariam), and therefore this drug is not appropriate as an anti-malarial in these regions.
Chloroquine resistance is also rife throughout the region, although this drug is rarely used as a malaria prophylactic drug. However, apart from this, the choice of anti-malarial depends to a large extent on personal preferences.
The two main types recommended by the CDC for travel to south-east Asia are atovaquone-proguanil (marketed commonly as Malarone) and doxycycline. The former is associated with very few side effects, is taken once a day, and needs to be taken for a week after returning from the malarial area. However it is also very pricey! Doxycycline, on the other hand, is very cheap, but many people experience high sun sensitivity which can lead to severe sun burn if sufficient care is not taken. It also has to be taken for a full four weeks after returning from the malarial area.