Tablet splitting is a highly inaccurate and potentially dangerous practice according to a study in the January issue of the Journal of Advanced Nursing. Pill splitting is a common practice among people who try to cut medication costs or dosage. It is not often possible to split a pill 50-50. There are drugs with a very low therapeutic index. Therapeutic index, a measure of the relative safety of the drug for a particular treatment, is the ratio between the toxic dose and the therapeutic dose of a drug. Pill splitting in drugs with a narrow margin between therapeutic and toxic doses can result in serious clinical consequences.
Not all pills are suitable for splitting. Drugs such as digoxin (commonly prescribed for cardiac conditions), lithium carbonate (used to treat psychiatric conditions like mania), warfarin (anticoagulant) and theophylline (used in respiratory ailments like asthma) have narrow therapeutic indices. Splitting such drugs lead to large dose deviations. The effects produced can be disastrous. †††††††
Tablet splitting is attempted by people for a number of reasons:
∑†††††††† To increase dose flexibility
∑†††††††† To make tablets easier to swallow
∑†††††††† To save money for both patients and healthcare providers
Split tablets are often unequal sizes. A substantial amount of the tablet can be lost during splitting. In the study performed at Faculty of Pharmaceutical Sciences at Ghent University, Belgium, five volunteers were asked to split eight different-sized tablets using three techniques commonly used in nursing homes: a kitchen knife, scissors/hands, or a pill splitter. The drugs used were the ones prescribed for a range of health conditions, including Parkinson's, congestive heart failure, thrombosis and arthritis.
Each fragment was weighed to see how much they deviated from the theoretical weight. It was found that 31 per cent of the tablet fragments deviated from their theoretical weight by more than 15 per cent and that 14 per cent deviated by more than 25 per cent. Even the most accurate means of pill splitting, the pill splitter, was associated with margins of error.† Handling the raw surface of split drug can also cause loss of its property† and its efficacy.
There is no clear-cut consensus on which pills you can, or can't, split. Extended-release tablets and capsules can't be cut. It is wise to ask a pharmacist or a physician before you split any pill. Using a splitting device is the most accurate method available howwevereven this can produce errors. Sometimes when splitting cannot be avoided, for example when the prescribed dose is not commercially available or where there is no alternative formulation, such as a liquid - this exercise should be undertaken by a qualified pharmacist.
The only solution to bring down the practice of pill splitting is to call on manufacturers to produce greater dose options and liquid alternatives. It is also important to increase public awareness, make people aware of the risks involved with the common practice.