Undertaking drug calculations for oral medicines and suppositories
Intended for healthcare professionals
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Undertaking drug calculations for oral medicines and suppositories

Jane Brindley Senior lecturer in Adult nursing, School of Nursing, Canterbury Christ Church University, Canterbury, England

Nurses are required to demonstrate knowledge and competence in undertaking drug calculations as part of their practice. This article aims to assist nurses in identifying their competence in undertaking drug calculations for oral medications and suppositories. Although nurses enter their professional register with an assessed level of medicines competence, nursing is a dynamic profession and competency can decrease over time, with literature demonstrating that nurses often have suboptimal drug calculation skills. This article enables nursing students to continue to enhance their knowledge and understanding of drug calculations, and registered nurses to revisit this element of an essential nursing skill. It provides examples of drug calculations, alongside methods and formulas that should be used. It also discusses issues that potentially compromise safe practice, and relates drug calculations to the professional standards outlined in UK nurses’ code of practice.

Nursing Standard. 32, 7, 56-63. doi: 10.7748/ns.2017.e10953




Peer review

This article has been subject to external double-blind peer review and checked for plagiarism using automated software

Conflict of interest

None declared


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Received: 13 July 2017

Accepted: 21 August 2017

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