Dosing of praziquantel by height in sub-Saharan African adults

Abstract

The cornerstone of schistosomiasis control is mass praziquantel treatment in high prevalence areas. Adults are an important target population, given increasing recognition of the burden of male and female genital schistosomiasis. However, use of weighing scales to calculate praziquantel dosing in rural areas can be challenging. For school-age children, the World Health Organization (WHO) has approved a dose pole to simplify praziquantel dosing based on height. We modified the pediatric dose pole by adding two height categories and incorporating a simple overweight/obesity adjustment, for simplified mass treatment of adults in sub-Saharan Africa. Using the rural Zimbabwean Demographic and Health Survey data, we show that the modified dose pole with body mass index adjustment would result in > 98% of adults receiving an acceptable dose (30-60 mg/kg), with only 1.4% and 0.3% receiving an inadequate dose (< 30 mg/kg) or high dose (> 60 mg/kg), respectively. An adult dose pole may provide a more feasible alternative to weighing scales in community-based praziquantel treatment programs.

Figures

Figure 1.

Body shape pictogram. Pictogram developed originally by Stunkard and others to evaluate body in shape Danish men and women, and subsequently adapted and validated in other populations. The optimal sensitivity and specificity for obesity in a Caucasian population uses the sixth figure for both men and women as the cut-off point; however, the optimal cut-off for overweight was not assessed. To our knowledge, no study to date has evaluated use of this pictogram to categorize body-mass index in sub-Saharan African populations. Reprinted from with permission from Elsevier.

Figure 2.

Dose pole models for praziquantel administration. Original World Health Organization (WHO) pediatric dose pole with height categories and corresponding number of 600 mg tablets to administer (left). Modified dose pole for adults with additional half-tablet categories and new height cut-offs in red (right). The tables below each pole show the percentage of adults who would have received an inadequate dose ( 60 mg/kg) of praziquantel.

Figure 3.

Dosing range of praziquantel in rural Zimabwean adults. Range of theoretical dose received by rural Zimbabwean adults based on their height category as determined by the original World Health Organization (WHO) dose pole (left), which has three height categories, and the modified dose pole (right), which has five height categories, without body mass index (BMI) correction (upper panels) and with BMI correction (lower panels). The dashed lines indicate the acceptable dose range of praziquantel (30–60 mg/kg).