The scored tablet--a source of error in drug dosing?

To determine the weight deviation of scored tablets after breaking we took 100 tablets of each of 34 brands of commercially available antihypertensive drugs and broke them into two, using the scored line. We graded the weights of the tablet halves according to their deviation from the expected weight (1 = less than or equal to +/- 5%, 11 = +/- 6-10%, 111 = greater than or equal to +/- 10%). The brands were ranked by the proportion of tablet halves (n = 200) in each category. Only seven brands divided very accurately and 11 brands divided reasonably accurately. Despite the scored line the remainder were either moderately (n = 10) or absolutely (n = 6) unsuitable for breaking, by hand or otherwise. A high proportion of these tablet halves showed weight deviations of 6-10% or more than 10% when compared to the expected weight. These findings show that a great number of antihypertensive drugs do not break evenly despite a scored line. This leads to inaccuracy of dosage.