Malaria Chemoprophylaxis Mode of Action

Hi, Apologies if this is a dumb question, but 1) What is the mode of operation of malaria chemoprophlaxis (it seems to me, the drugs are the same as those used to treat malaria, so is the mechanism of action just to have your body filled with drugs which will destroy any plasmodium which comes into the system?) 2) Why do you have to start prophylaxis a week or so before going into the malaria area Thanks in advance
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums