Healthcare workers are being urged to stop splitting tablets in half because it can reduce the dosage of medication by over a quarter.

A study, published in The Journal of Advanced Nursing discovered that splitting tablets affects dosage by at least 15 per cent, which is worrying because some tablets have a very narrow margin between being therapeutic and toxic.

It's important news for those in domiciliary care jobs, who often face splitting tablets to help patients swallow, for example. The study has led to calls for training on how to split pills effectively, if it cannot be avoided, and better education on the medicines which shouldn't ever be split.

That's because, according to Dr Charlotte Verrue, who led the study, split tablets "are often unequal sizes and a substantial amount of the tablet can be lost during splitting". She added: "This could have serious clinical consequences for drugs where there is a small difference between therapeutic and toxic doses."

"Staff who are responsible for splitting tablets should receive training to enable them to split as accurately as possible," added Dr Verrue. "They should also be made aware of the possible clinical consequences of dose deviations."

The study asked volunteers to split eight different sized tablets using the three most common techniques. They had no previous experience of splitting pills, which was done to mimic how people without training halve tablets. Researchers found that one in three tablets saw their weight change by more than 15 per cent. Of those tablets, 14 per cent of tablets had changed weight by over a quarter.

Dr Verrue explained that those in domiciliary care jobs, and other healthcare professionals, split pills: "to increase dose flexibility, to make tablets easier to swallow and to save money both for patients and healthcare providers."