Splitting medication tablets could be dangerous for patients

Kathleen Blanchard's picture

The common practice of splitting medication tablets could have serious consequences.

Medical experts writing in the Journal of Advanced Nursing warn that even when a pill splitter is used there is still a 15 to 25 percent margin of error that the wrong medication dose will be delivered.

Researchers from the Faculty of Pharmaceutical Sciences at Ghent University, Belgium enlisted volunteers who split eight different sized tablets using the three most common techniques - a splitting device, or "pill cutter", scissors and a kitchen knife.

Between the five volunteers, the medications were cut into 3,600 separate quarters or halves. The pills were different shapes. Two were scored (having a groove), an option designed by pharmaceutical companies to allow ease of cutting medications in half or quarters. Three of the drugs were not scored.

Many of the drugs examined were for serious conditions like Parkinson's disease, congestive heart failure, blood clot and arthritis.

The study found using a pill cutter or splitting device was the most accurate, but still resulted in a 15 to 25 per cent error margin 13 percent of the time, meaning the wrong dose of medication would be taken. Eight percent of the time, the deviation was more than 25 percent. The error margin for splitting medication using scissors or a knife was 22 and 17 percent respectively.


A more than 25 percent error occurred 19 per cent of the time using scissors and 17 per cent of the time using a knife.

The researcher say cutting or splitting pills "is done for a number of reasons: to increase dose flexibility, to make tablets easier to swallow and to save money for both patients and healthcare providers. However, the split tablets are often unequal sizes and a substantial amount of the tablet can be lost during splitting."

Lead study author, Dr Charlotte Verrue says pill cutting is a common practice in nursing homes, but even the most accurate method of splitting medications produces errors that were found in the study by weighing the tablet pieces and fragments.

She recommends health care staff receive special training to make them aware of the consequences of pill splitting, also suggesting staff learn how to do so as accurately as possible.

Verrue explains, "...not all formulations are suitable for splitting and, even when they are, large dose deviations or weight losses can occur. This could have serious clinical consequences for drugs where there is a small difference between therapeutic and toxic doses.

The study authors propose that pharmaceutical companies provide liquid medication options to help patients avoid the dangers of trying to split medications in half or quarters that could lead to improper dosing. When it’s necessary to cut pills, the researchers say it should be done with a pill cutter designed to provide the best accuracy. Whenever possible choose a liquid medication.

JAN: DOI: 10.1111/j.1365-2648.2010.05477.x