(2003; 77 pages)
Praziquantel 'dose pole' for large scale deworming
The usefulness of dose poles, used to decide the appropriate drug dose on the basis of people's height instead of their weight, has been demonstrated in the Onchocerciasis Control Programme in West Africa, where it has been used extensively for ivermectin administration. The same type of dose pole has now been developed for the administration of praziquantel in sub-Saharan Africa and validated in 12 data sets from ten African countries, totalling 25 688 people.
Of the 25 688 individuals in the data sets, 1055 (or 4.1%) had a height that did not fit the interval identified by the pole (110-178 cm). Of the remaining 24 633 people, 81.6% would have received a dose of praziquantel between 40 mg/kg and 60 mg/kg, and 98% a dose between 30 mg/kg and 60 mg/kg, had the number of tablets been determined with the dose pole. The dose pole performed particularly well in school age children, where 84.7% would have received a dose of praziquantel between 40 mg/kg and 60 mg/kg, and 98.6% a dose between 30 mg/kg and 60 mg/kg (1).
For the control of morbidity due to schistosomiasis and soil-transmitted helminthiasis, WHO currently recommends that good quality anthelminthic drugs, including praziquantel, be available at all levels of the health care system in endemic areas, and that groups at a high risk of morbidity should have access to regular treatment. Regular deworming, particularly in school age children, will help to avoid the worst effects of infection even if there is no improvement in safe water supply or sanitation. Treatment with any of the anthelminthic drugs on the WHO Model List of Essential Medicines (albendazole, levamisole, mebendazole, or pyrantel for soil-transmitted helminths, and praziquantel for all types of schistosomiasis) is safe, even when given to uninfected children. There is therefore no need to examine each child for the presence of worms. Individual sceening offers no safety benefits. And it is not cost-effective; costing four to ten times more than the anthelminthic treatment itself. The WHO recommendations on how frequently to deliver targeted treatment to high risk groups in different endemic situations have recently been revised (2).
It is expected that the newly developed praziquantel dose pole will greatly facilitate the delivery of regular treatment in endemic areas, particularly to school age children, and help to consolidate large-scale control efforts (3).
1. Montresor, A., Engels, D., Chitsulo, L. et al. Development and validation of a 'tablet pole' for the administration of praziquantel in sub-Saharan Africa. Transactions of the Royal Society of Tropical Medicine and Hygiene, 95: 542-544 (2001).
2. World Health Organization. The Prevention and Control of Schistosomiasis and Soil-transmitted helminthiasis. Report of a WHO Expert Committee. Technical Report Series, No. 912 (2002).
3. Savioli, L., Stansfield, S., Bundy, D.A.P. et al. Schistosomiasis and soil-transmitted helminth infections: forging control efforts. Leading Article. Transactions of the Royal Society of Tropical Medicine and Hygiene, 96: 577-579 (2002).