Remember: Prevention is better than cure and over two million people die from malaria every year. It is a very serious illness! Side Effects of Anti-Malarials Like all medicines, anti-malarials can sometimes cause side-effects: Proguanil (Paludrine) can cause nausea and simple mouth ulcers. Chloroquine (Nivaquine or Avloclor) can cause nausea, temporary blurred vision and rashes. Patients with a history of psychiatric disturbances (including depression) should not take mefloquine as it may precipitate these conditions. It is now advised that mefloquine be started two and a half weeks before travel. Doxycycline does carry some risk of photosensitisation i.e. can make you prone to sunburn. Malarone is a relatively new treatment and is virtually free of side effects. It is licensed for use in stays of up to 28 days but there is now experience of it being taken safely for up to three months. No other tablets are required with mefloquine or doxycycline or Malarone. Drug Resistance  It is the plasmodia that cause malaria that develop resistance to anti-malarial drugs not the mosquitoes that transmit the disease. Resistance to antimalarial drugs is proving to be a challenging problem in malaria control in most parts of the world. Since the early 60s the sensitivity of the parasites to chloroquine, the best and most widely used drug for treating malaria, has been on the decline. Drug resistance is the ability of a parasite species to survive and multiply despite the administration of a drug in doses equal to or higher than those usually recommended but within the limit of tolerance. Newer antimalarials have been developed in an effort to tackle this problem, but all these drugs are either expensive or have undesirable side effects. The discovery of chloroquine revolutionalised the treatment of malaria, pushing quinine to the sidelines. However, after a variable length of time, the parasites, especially the falciparum species, have started showing resistance to these new drugs. Resistance is most commonly seen in P. falciparum whereas only sporadic cases of resistance have been reported in P. vivax malaria. Resistance to chloroquine is most prevalent, while resistance to most other antimalarials has also been reported. Resistance to chloroquine began from two epi-centres; Colombia (South America) and Thailand (South East Asia) in the early 1960s. Since then, resistance has been spreading world wide. Recently, cases of mefloquine resistance have been reported from areas of Thailand bordering with Burma and Cambodia (see map above). Travellers to Thailand are therefore advised to avoid using mefloquine when travelling to these risk areas. Because mefloquine is structurally similar to chloroquine, cross resistance is possible due to the prolonged half life of mefloquine.