The WHO dose pole for the administration of praziquantel is also accurate in non-African populations

Abstract

SummaryIn 2001, WHO developed a pole for the administration of praziquantel without the use of weighing scales with encouraging results in African populations. In the present study, the pole was tested on height/weight data from 9,354 individuals from 11 non-African countries. In more than 98% of the individuals (C.I. 97.8-98-4) the pole estimated an acceptable dosage (30-60 mg/kg) -a performance not statistically different from the one observed in African populations. Reproducing the present pole in the form of a strip of paper and including it in each container of praziquantel would greatly facilitate the administration of the drug in large-scale interventions. Keywords Praziquantel administration; WHO dose poleThe regular treatment of vulnerable groups with praziquantel is WHO's principal strategy for schistosomiasis control (WHO 2003). The drug administration is simple, but, as the individual dose of praziquantel is given according to body weight, reliable weighing scales are necessary in the field, which can be problematic and expensive. Hall et al (1999) therefore suggested the use of a pole, which estimates the number of tablets needed for treatment according to an individual's height. Three poles based on data from Ghana, Malawi and Tanzania were developed and tested in each country (n=1,803, n=2,069 and n= 2,078 respectively) with positive results (Hall et al. 1999 The present study was conducted to investigate the validity of the WHO dose pole to indicate dosage of praziquantel in non-African populations. Our analysis was conducted on height-weight data previously randomly collected from 11 countries. The total number of records was 9,356, of which 7,453 were children aged between 6 and 15 years (school age).Seven data sets originated from schistosomiasis-endemic countries (including all major nonAfrican endemic countries). Four data sets, from non-endemic countries were, also included in the analysis to further confirm the worldwide validity of the WHO dose pole. Sixteen records (0.17%) were excluded from the analysis as suspected data entry errors since the weight was more than 3 standard deviations from the expected value for height.Two height intervals: between 94 cm and 110 cm (corresponding to 1 tablet) and over 178 cm (5 tablets) were added to the WHO pole (Figure 1). These new thresholds were calculated using the same equation used to define the original thresholds between 110 and 178 cm [y = 0.005x 2 -0.7909x + 44.647] .Each person's height was classified using the pole's intervals and the number of tablets and the total dose (in mg) indicated by the pole was recorded. The individual dosage was then calculated by dividing the total dose by the weight of each individual registered in the data set (in mg/kg).A dosage between 40 -60 mg/kg was considered optimal (WHO 2004) and a dosage between 30-60 mg/kg was considered acceptable for the significant activities demonstrated by praziquantel at this dosage (Taylor et al 1988).The average dose provided by the WHO pole was 44.74 mg/Kg (range 42.06 mg/...

Dosing of Praziquantel by Height in Sub-Saharan African Adults

“…An optimal dose of praziquantel was defined as 40-60 mg/kg, with an acceptable dose defined as 30-60 mg/kg. 2,3,9 We reasoned that adults could easily be classified as overweight or obese by fieldworkers using a pictogram (Figure 1). 10,11 Adults with body mass index (BMI) 25 kg/m 2 were estimated to require an additional 25% of the average adult dose (2,400 mg), translating to one extra 600 mg tablet ( (Figures 2 and 3).…”

“…1 Given the challenges of using a weighing scale in rural households, praziquantel dosing for children has been simplified by use of a vertical "dose pole" that uses height as a surrogate for weight to estimate the correct dose of praziquantel for each child. 2,3 This dose pole has recently been modified for preschool-age children, a vulnerable target group previously excluded from mass drug administration (MDA) programs. 4,5 Adults are generally dosed according to body weight, despite the logistical challenge of accurate weight measurement in rural areas of developing countries.…”

Schistosomiasis: challenges for control, treatment and drug resistance

“…One innovation that has simplified the task of delivery of the correct dosage of PZQ to school-aged children is the development and validation of a 'dose pole' specific for PZQ [16]. The pole is marked off in tablets so that teachers and community health workers can determine the dosage to be dispensed to every child according to his/ her height rather than weight.…”

“…The pole is marked off in tablets so that teachers and community health workers can determine the dosage to be dispensed to every child according to his/ her height rather than weight. Montresor et al [16] demonstrated that by using the dose pole, children are given the correct dosage within an acceptable range. This means that weighing children (on often unreliable scales) and calculating the numbers of tablets (which is prone to error) are no longer necessary.…”

Morbidity due to Schistosoma mansoni: an epidemiological assessment of distended abdomen syndrome in Ugandan school children with observations before and 1-year after anthelminthic chemotherapy

“…An appropriate medication of 40 mg/kg praziquantel for S. mansoni, as calculated by child's height according to the amended WHO height pole (Montresor et al, 2005), and a single 400 mg albendazole tablet for intestinal helminths were administered to each child. Children were monitored after treatment for any immediate adverse reactions.…”