Antimalarial drug therapy
Antimalarial drug therapy needs expert advice due to drug resistance and side effects, and you should do it right before you go on vacation. This article provides a brief overview of popular antimalarials 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 checkups are recommended after three years of chloroquine use. Extensive experience suggests that its use is safe during pregnancy, although it is recommended that 5 mg of folic acid daily be added to the regimen during pregnancy when taking proguanil. Unfortunately, there is now widespread resistance to these drugs, making them much less effective in some parts of the world.
Depending on the area to visit, they are taken alone or together. Travelers should start taking antimalarials at least a week before travel, primarily to ensure they don’t react to the medication, continue while there and for at least four weeks after leaving a malarial area. The usual dose for adults 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, aside from an unpleasant taste, are nausea, upset stomach, and mouth ulcers. Chloroquine should not be taken by people who currently have epilepsy or who have had epilepsy in the past, or by people who have psoriasis, a common skin disorder.
There has been much controversy surrounding the use of mefloquine known as Larium for malaria prophylaxis. Media publicity and conflicting medical advice have led to confusion, and subsequently some travelers do not take any pharmacological prophylaxis in countries where it is recommended. This could lead to a life-threatening malaria infection. Every traveler should consider the pros and cons of mefloquine and decide if the drug is right for them.
All medications have side effects, and studies have shown that mefloquine can cause problems such as dizziness, headache, insomnia, vivid dreams, and depression in some people, and that these problems seem to affect women more than men. A recent study showed that about a quarter of people taking mefloquine and an eighth of those taking chloroquine and proguanil experienced problems. Some studies have shown that in about 1 in 10 people, side effects interfered with planned activities, and in 1 in 10,000 people a serious side effect occurred.
Some of the side effects experienced with mefloquine, especially headaches and vivid dreams, can be relieved by taking half a tablet twice a week. Most side effects of mefloquine start within three weeks of starting the drug and go away within three weeks of stopping it. It is recommended that you start taking mefloquine at least two weeks before you travel so that if side effects occur, you can switch to an alternative drug.
Studies from Africa show that mefloquine is more effective in preventing malaria infection than a combination of chloroquine and proguanil, 90 percent compared to 60 to 70 percent. Mefloquine is also convenient to take, as it is a weekly dose, and is now licensed for up to one year. However, it is relatively expensive. If travelers tolerate mefloquine and remain at high risk of malaria infection, it is recommended to continue for 2 to 3 years. Mefloquine has been used by more than 6,000 Peace Corps workers for 2-3 years with no evidence of serious adverse reactions.
Mefloquine is the first choice for areas where there is widespread resistance to chloroquine, such as sub-Saharan Africa, the Amazon basin, and parts of Southeast Asia. Mefloquine is not suitable for everyone and is not recommended for the following women in the first 12 weeks of pregnancy, women who are breastfeeding, or women who could become pregnant within three months of taking the last tablet. However, evidence is accumulating that women who took mefloquine in early pregnancy, or just before becoming pregnant, do not appear to have an increased risk of having a child with birth defects compared to background risk.
People with a history of epilepsy or a strong family history of epilepsy. People who have any mental health problems, for example depression, anxiety attacks or mood disorders. People who have heart rhythm problems. People whose work depends on a high degree of coordination, such as airline pilots or professional divers.
It is not suitable for small children under 5 kg. For children between 5 and 13 kg it is difficult to break the tablets to obtain 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 needed . So far no pediatric formulations are 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 the UK authorities recommend it primarily for travelers to the Thailand/Myanmar (Burma) and Thailand/Cambodia border areas, as well as to the Western Province of Cambodia, where falciparum malaria is usually resistant to both chloroquine and mefloquine. Studies show that doxycycline provides about 85 percent protection against malaria infection, although this effectiveness declines rapidly if compliance is poor. Doxycycline is increasingly being used by higher-risk travelers to sub-Saharan Africa if mefloquine is contraindicated or if there is reluctance to take it.
Doxycycline is recommended for short-term prophylaxis, for 3-4 months, and concerns about potential side effects restrict its use any longer. By balancing these side effects, doxycycline provides good protection against malaria and also reduces the incidence and duration of traveler’s diarrhea.
Pregnant women or children under the age of ten should not take doxycycline. American recommendations allow its use in children from eight years of age. It should be taken with copious amounts of fluid to prevent ulceration and discomfort in the esophagus. The main side effect is that some people become very sensitive to the sun and burn easily. Doxycycline interferes with the contraceptive pill and it is recommended that women also use barrier methods of contraception in the first two weeks of starting doxycycline. Women who take doxycycline regularly may be prone to recurrent vaginal yeast infection.
Malarone is a combination of atovaquone and proguanil, and you should not take it if you are allergic to proguanil or atovaquone. People with kidney disorders should not take Malarone. The same applies to people suffering from depression, mental illness and epilepsy. If you are pregnant or planning to become pregnant, talk to your doctor, but the best advice is probably to stay away from regions with malaria.
Finally, even if you have taken all the precautions you can think of, if you have a fever see a doctor, even if it is some time after your return. You can’t be too careful, and remember that no medication works 100% of the time, so don’t forget all other preventive measures.