Physicians frequently recommend that caregivers split pills to give patients smaller doses than are available by prescription, but that process can produce wide variation in dosages, particularly if a commercial pill-splitter is not used and often even if one is employed, Belgian researchers say. The practice can be a particular problem for drugs in which a precise dosage is crucial with measured dosages off by 25% or more in some cases, they reported in the Journal of Advanced Nursing, and they called on drug manufacturers to make more dosages of some of the more problematic drugs available.
Pharmaceutical scientist Charlotte Verrue of Ghent University and her colleagues asked five volunteers to split 10 samples each of eight different medicines commonly split in nursing homes. Three were unscored, three had one score line and two had two scores. They were split with a commercial splitter, scissors and a kitchen knife. The drugs included Marevan, Lanoxin, Merck-Metformine, Sinemet, Marcoumar, Aldactone, Medrol and Zestril.
Using the splitting device was simplest, but it still produced a 15% to 25% error in 13% of the cases. That was lower than the 22% of cases for scissors and 17% for the knife, however.
The splitter produced an error of more than 25% in 8% of cases, compared with 19% for the scissors and 17% for the knife.
Tablet splitting is widespread in all healthcare sectors, the authors said, and a study in Germany showed that about a quarter of all drugs are split, either to titrate dosage or to reduce cost. “We would...like to see manufacturers introduce a wider range of tablet doses or liquid formulations so that tablet splitting becomes increasingly unnecessary,” they wrote.