Evaluation of the ability of pharmacy and medicine students to calculate drug dosage


  • Lynne Meyler School of Pharmacy, Royal College of Surgeons in Ireland, York St., Dublin 2.
  • Zevunnssa Ramtoola
  • James Barlow School of Pharmacy, Royal College of Surgeons in Ireland, York St., Dublin 2.


Drug dose calculations, pharmacy, medical students


Background:Theskillsandcompetenciesofhealthcareprofessionalshavebecomeanincreasingfocusofhealthcareresearch. It has been reported that many newly graduated healthcare professionals have low levels of competency in the area of drug dose calculation.
Aims: To assess the ability of healthcare students at our institution to perform drug dose calculations and to obtain the opinions of those students regarding perceived calculations competency and training.
Methods: First and final year pharmacy students and final year medicine students were invited to complete a questionnaire, consisting of drug dose calculations and opinion questions.
Results: The results showed that final year students were competent in calculating dosages based on body surface area and those expressed in international units (IU). They were competent in calculating renal function and the number of tablets required for a prescription. However, 83.5% of students had difficulties interpreting strengths or doses of drugs.
Conclusion: Drug dose calculation continually provides challenges among healthcare graduates, and additional and varied learning resources may enable students to attain and retain an acceptable standard of skill throughout their professional careers.


Degnan, B. A., Murray, L.J., Dunling, C.P., Whittlestone, K.D., Standley, T.D.A., Gupta, A.K., Wheeler, D. (2006) The effect of additional teaching on medical students’ drug administration skills in a simulated emergency scenario. Anaesthesia, 61, 1155-1160.

Glover, M.L., Sussmane, J.B. (2002) Assessing pediatriatics residents’ mathematical skills for prescribing medication: a need for improved training. Academic Medicine, 77, 1007-1010.

Oldridge, G.J., Gray, K.M., McDermott, L.M., Kirkpatrick, C.M.J. (2004) Pilot study to determine the ability of health-care professionals to undertake drug dose calculations. Internal Medicine Journal, 34, 316-319.

Preacher, K. J. (2001) Calculation for the chi-square test: An interactive calculation tool for chi-square tests of goodness of fit and independence [Computer software]. Available from http:// www.quantpsy.org.

Rolfe, S., Harper, N.J.N. (1996) Ability of hospital doctors to calculate drug doses. British Medical Journal, 310, 1173-1174.

Smith, N.A., Wheeler, D.W. (2010) Intensive teaching of drug calculation skills: the earlier the better. Quality and Safety in Health Care, 19, 158.

Wheeler, D.W., Degnan, B.A., Murray, L.J., Dunling, C.P., Whittlestone, K.D., Wood, D.F., Smith, H.L., Gupta, A.K. (2008) Retention of drug administration skills after intensive teaching. Anaesthesia, 63, 379-384.

Wheeler, D.W., Remoundos, D.D., Whittlestone, K.D., Palmer, M.I., Wheeler, S.J., Ringrose, T.R., Menon, D.K. (2004) Doctors’ confusion over ratios and percentages in drug solutions: the case for standard labelling. Journal of the Royal Society of Medicine, 97, 380-383.

Wheeler, D.W., Wheeler, S.J. (2004) Dose calculation and medication error – why are we still weakened by strengths? European Journal of Anaesthesiology, 21, 929-931.

Wheeler, D.W., Wheeler, S.J., Ringose, T.R. (2007) Factors influencing doctors’ ability to calculate drug doses correctly. International Journal of Clinical Practice, 61, 189-194.

Wright, K. (2006) Barriers to accurate drug calculations. Nursing Standard, 20, 41-45.

Wright K. (2007) Student nurses need more than maths to improve their drug calculating skills. Nurse Education Today, 27, 278-285.



Research Article