Editor—Croft has written about preventing malaria in travellers.1 Malaria is more common and more severe in children and pregnant women, and clear recommendations regarding prevention in these groups are crucial.
Case reports of potential toxicity caused by diethyltoluamide in children and pregnant women are poorly documented, and in most cases use of the repellent was excessive. A retrospective study of 9086 reports of diethyltoluamide toxicity found that children were no more likely to develop adverse effects than adults.2 Almost two thirds of those exposed had no adverse effects, and 99% had no long term sequelae. Diethyltoluamide is the most effective insect repellent and should be recommended for children and adults, including pregnant women, in concentrations of up to 30%.
Croft does not provide sufficient information about the studies concerning use of mefloquine in childhood and pregnancy.3,4 Luxemburger et al documented the efficacy and tolerability of mefloquine in 417 children aged between 3 months and 5 years.3 The only side effects were gastrointestinal, the major one being early vomiting. This is not a substantial problem, however, in children given prophylactic doses. Serious neuropsychiatric adverse effects have not been described in children given mefloquine for prophylaxis.
One of the preliminary findings from Nosten et al's study in pregnancy was a significant excess of stillbirths in women given mefloquine, although this was not borne out in the overall analysis.4 Moreover, only women in the second and third trimesters of pregnancy were included. Subsequent studies of the use of mefloquine beyond the first trimester have had conflicting results; some data suggest that mefloquine may be safe throughout pregnancy. The excretion into breast milk is minimal.
In conclusion, mefloquine is an acceptable choice for prophylaxis in children from 3 months of age (weighing over 5 kg). Whether it is safe in pregnancy remains unclear, although many authorities recommend its use for prophylaxis beyond the first trimester. It is safe for use during lactation.
Doxycycline forms a stable calcium complex in any bone forming tissue, and a resultant decrease occurs in the growth rate of long bones in the fetus and newborn infant. It is also deposited in teeth, causing discoloration until mineralisation is completed at age 6. Tetracyclines cross the placenta and are excreted in breast milk, but absorption by infants is negligible.5 Doxycycline should not be used in children under 8 years old or in pregnant women. It should also be avoided in lactating women if there is an appropriate alternative.
References
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