Drug calculations: are they safer with or without a calculator?

The safe administration of medicines is a key nursing activity. The most common type of medication error is administering the wrong dose (Armitage, 2006). To administer medicines correctly, nurses must apply appropriate knowledge specific to the patients receiving medication, and execute the skills required to administer medicines to a high degree of accuracy. This may include mathematical calculations. The potential for errors in child health settings is compounded by the complex calculations often required to ensure children receive the appropriate dose. Nurse educators face dilemmas in both pre- and post-registration settings relating to students' lack of ability to undertake drug calculations without a calculator. This means that students may not be able to follow the Nursing and Midwifery Council (NMC) Guidelines for the Administration of Medicines (NMC, 2004b). Medication dosage calculations continue to be problematic for qualified nurses. It is too early to assess whether changes in state education will improve pre-registration students' abilities to apply skills in basic mathematical principles to drug calculations. In the meantime, it is important that nurses who appear to have a weakness in applying mathematical principles to drug calculations seek, and are offered, the opportunity to develop these skills.