Community based ivermectin therapy for onchocerciasis: Comparison of three methods of dose assessment

A new method of assessment based on mid-upper arm circumference (MUAC) is described for dosage adjustment for community-based ivermectin distribution. We studied 878 subjects eligible for ivermectin dosing in Awhum, Nigeria. In a previous preliminary study of 40 persons, MUAC (in cm) correlated with weight (kg) in the first 20 male (r = 0.97, r(2) = 0.95, P < 0.0001) and the first 20 female subjects (r = 0.94, r(2) = 0.88, P < 0.0001). We therefore studied the use of height, physical appearance, and MUAC for calculating the dose of ivermectin. The MUAC-based schedule underdosed only 4.1% of the population. The methods based on height underdosed 3.3% and 21.1%, and assignment based on physical appearance underdosed 10.2% of the population studied. This MUAC-based method (13-15 cm, 0.5 tablet; 16-20 cm, 1.0 tablet; 21-27 cm, 1.5 tablets; greater than or equal to 28 cm, 2.0 tablets) is more convenient and corresponds closely to dosing by weight. An adaptation of this method with reference to other prevalent tropical diseases and their respective drugs is therefore advocated.