Anti Malarial Drug Therapy needs the advice of an expert because of drug resistance, and side effects, and you must do this well before leaving on vacation. This article gives a brief summary of the popular anti malarials, and their potential side effects.
Chloroquine and Proguanil known as Paludrine are the oldest and most widely used. They are safe to take long-term, however, annual eye check-ups are recommended after three years of chloroquine use. The wealth of experience suggests that they are safe to use during pregnancy although it is recommended that folic acid 5 mgs daily is added to the regimen during pregnancy when proguanil is taken. Unfortunately, there is now widespread resistance to these drugs, rendering them much less effective in some parts of the world.
Depending on the area to be visited, they are either taken alone or together. Travellers should start anti-malarials at least a week before travel, mainly to make sure that they do not react to the medication, continue whilst there and for at least four weeks after leaving a malaria area. The usual adult dose is chloroquine two tablets once a week together with proguanil two tablets daily, making a total of sixteen tablets per week.
The main side-effects of the chloroquine/proguanil combination, apart from an unpleasant taste, are nausea, stomach upsets and mouth ulcers. Chloroquine should not be taken by people who are currently suffering from epilepsy or have had epilepsy in the past, or by people who suffer from psoriasis, a common skin disorder.
There has been a lot of controversy surrounding the use of mefloquine known as Larium for malaria prophylaxis. Publicity in the media and conflicting medical advice have led to confusion, and subsequently some travellers are not taking any drug prophylaxis at all for countries where it is recommended. This could lead to potentially life-threatening malaria infection. Every traveller needs to consider the pros and cons of mefloquine and decide if the drug is suitable for them.
All drugs have side effects, and studies have shown that mefloquine can cause problems such as dizziness, headache, insomnia, vivid dreams and depression in a few people, and that these problems seem to affect women more than men. A recent study showed that around a quarter of those people taking mefloquine and an eighth taking chloroquine and proguanil experienced problems. Some studies have shown that, in about one in ten people, the side effects interfered with planned activities and in one in 10,000 people a severe side effect occurred.
Some of the side effects experienced with mefloquine, especially headaches and vivid dreams, may be helped by taking half a tablet twice a week. The majority of side effects with mefloquine start within three weeks of starting the drug and stop within three weeks of stopping. It is recommended that you start mefloquine at least two weeks before travelling so that if any side-effects occur you can change to an alternative drug.
Studies from Africa show that mefloquine is more effective at preventing malaria infection then a combination of chloroquine and proguanil, 90 per cent compared to 60-70 per cent. Mefloquine is also convenient to take as it is a weekly dose, and it is now licensed to be used for up to one year. However, it is relatively expensive. If travellers are tolerating mefloquine and remain at high risk of malaria infection, it is advisable to continue for 2-3 years. Mefloquine has now been used by over 6,000 Peace Corps workers for 2-3 years without evidence of serious adverse reaction.
Mefloquine is first choice for areas where there is widespread chloroquine resistance, such as sub-Saharan Africa, the Amazon basin and parts of South-East Asia. Mefloquine is not suitable for everyone and it is not recommended for the following women in the first 12 weeks of pregnancy, women who are breast-feeding or women who might become pregnant within three months of taking the last tablet. However, evidence is accumulating that women who have taken mefloquine in the early stages of pregnancy, or just prior to becoming pregnant, do not appear to have an increased risk of having a child with congenital problems compared to the background risk.
People with a history of epilepsy or a strong family history of epilepsy. People who have any mental health problems, e. g. depression, anxiety attacks or mood disturbances. People who have cardiac rhythm problems. People whose jobs depend on a high degree of co-ordination, such as airline pilots or professional divers.
It is not suitable for young children under 5 kg. For children between 5-13 kg it is difficult to break up the tablets to get the correct dose, which is 5 mg/kg, since the tablet contains 250 mg of mefloquine, and therefore less than a quarter of a tablet is required. As yet there are no paediatric formulations available. Finally people with liver problems or severe kidney disease.
The third alternative is an antibiotic called doxycycline, a form of tetracycline. This is particularly popular with Australian travellers, but British authorities mainly recommend it for travellers to the border areas of Thailand/Myanmar (Burma) and Thailand/Cambodia, as well as the western province of Cambodia, where falciparum malaria is often resistant to both chloroquine and mefloquine. Studies show that doxycycline gives around 85 per cent protection against malaria infection, though this effectiveness quickly falls if compliance is poor. Doxycycline is increasingly being used by the higher risk traveller to sub-Saharan Africa if mefloquine is contra-indicated or if there is a reluctance to take it.
Doxycycline is recommended for short term prophylaxis, for 3-4 months, and concern about possible side effects restricts its use for longer. Balancing these side effects, doxycycline provides good anti-malarial protection and also reduces the incidence and duration of travellers’ diarrhoea.
Doxycycline should not be taken by pregnant women or children under the age of ten. American recommendations allow its use in children aged eight or over. It should be taken with liberal quantities of fluid to prevent ulceration and discomfort in the oesophagus. The main side-effect is that some people become very sensitive to the sun and become sunburnt easily. Doxycycline interferes with the contraceptive pill and it is recommended that women also use barrier methods of contraception in the first 2 weeks of starting doxycycline. Women taking regular doxycycline maybe prone to recurrent vaginal thrush.
Malarone is a combination of atovaquone and proguanil, and you should not take it if you are allergic to either proguanil or atovaquone. People with kidney disorders, should not take Malarone. The same applies for people suffering from depression, mental illness and epilepsy. If you are pregnant or planning on becoming pregnant, talk to your doctor, but the best advice is probably to stay away from Malaria regions.
Finally even if you have taken every precaution you can think of, if you feel feverish go to a doctor, even if it is some time after you return. You can’t be too careful, and just remember no medication works 100% of the time so don’t forget all the other preventative measures.