Laurence Goldberg, an independent pharmaceutical consultant, discusses the effectiveness and also the potential for harm of unit-dose medicines distribution.
In unit-dose dispensing, medication is dispensed in single doses in packages that are ready to administer to the patient. It can be used for medicines administered by any route, but oral, parenteral, and respiratory routes are especially common.
The system provides a fully closed-loop process where the patient, the drug and the healthcare professional are identified by machine readable codes and the drug administration process is linked directly to the electronic prescription and is fully recorded
There are many variations of unit-dose dispensing. As just one example, when doctors write orders for inpatients, these orders are sent to the central pharmacy. Pharmacists verify these orders and technicians place drugs in unit-dose carts. The carts have drawers in which each patient's medications are placed by pharmacy technicians—one drawer for each patient. The drawers are labelled with the patient's name, ward, room and bed number. Sections of each cart containing all medication drawers for an entire nursing unit often slide out and can be inserted into wheeled medication carts used by nurses during their medication administration cycles.
Alternatively, electronic medicine storage cabinets can be located on wards and these are attached to medicine carts which are then filled from the cabinets.
Studies often compare unit-dose dispensing to a ward stock system. In a ward stock system, bulk supplies are issued from the pharmacy; the drugs are stored in a medication room on the ward. The correct number of doses must be taken out of the correct medication container for each cycle and taken to the patient for administration. Liquids must be poured by the nurse from the appropriate bottle and each dose carefully measured.
Evidence for effectiveness of the practice
Though the practice of unit-dose dispensing is generally well accepted and has been widely implemented, the evidence for its effectiveness is modest. Most of the published studies reported reductions in medication errors of omission and commission with unit-dose dispensing compared with alternative dispensing systems such as ward stock systems.
Potential for harm
Unit-dosing shifts the effort and distraction of medication processing, with its potential for harm, from the ward to central pharmacy. It increases the amount of time nurses have to do other tasks but increases the volume of work within the pharmacy. Like the nursing units, central pharmacies have their own distractions that are often heightened by the unit-dose dispensing process itself and errors do occur.
Overall, unit-dose appears to have little potential for harm. The results of most of the observational studies seem to indicate that it is safer than other forms of institutional dispensing. However, the definitive study to determine the extent of harm has not yet been conducted.
A major advantage of unit-dose dispensing is that it brings pharmacists into the medication use process at another point to reduce error. Yet about half of the hospitals in a national survey indicated that they bypass pharmacy involvement by using floor stock, borrowing patients' medications and hiding medication supplies.
Unit dose drug distribution is being introduced across Europe. In Germany, a recent study showed a saving of 2.61 WTE nurses per 100 beds. There is now growing interest in UK hospitals and pilot sites to develop the system are being established.
What are your thoughts on unit-dose dispensing?
About the Author
Laurence is an independent pharmaceutical consultant working broadly in areas that are designed to reduce medication errors such as IV compounding robots, planning and organising seminars with a focus on medication error reduction, medical devices and environmental monitoring for hazardous drugs. He is a former NED of the National Patient Safety Agency.