Ability of medical students to calculate drug doses in children after their paediatric attachment

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Kazeem A. Oshikoya
Idowu O. Senbanjo
Ayo Soipe


Drug Dosage Calculations, Clinical competence, Students, Medical Pediatrics, Nigeria


Dose calculation errors constitute a significant part of prescribing errors which might have resulted from informal teaching of the topic in medical schools.

Objectives: To determine adequacy of knowledge and skills of drug dose calculations in children acquired by medical students during their clinical attachment in paediatrics.

Methods: Fifty two 5th year medical students of the Lagos State University College of Medicine (LASUCOM), Ikeja were examined on drug dose calculations from a vial and ampoules of injections, syrup and suspension, and tablet formulation. The examination was with a structured questionnaire mostly in the form of multiple choice questions.

Results: Thirty-six (69.2%) and 30 (57.7%) students were taught drug dose calculation in neonatal posting and during ward rounds/ bed-side teaching, respectively. Less than 50% of the students were able to calculate the correct doses of each of adrenaline, gentamicin, chloroquine and sodium bicarbonate injections required by the patient. Dose calculation was however relatively better with adrenalin when compared with the other injections. The proportion of female students that calculated the correct doses of quinine syrup and cefuroxime suspension were significantly higher than those of their male counterparts (p<0.05 and p<0.01, respectively; Chi-square test). When doses calculated in mg/dose and mL/dose was compared for adrenalin injection and each of quinine syrup and cefuroxime suspension, there were significant differences (adrenaline and quinine, p=0.005; adrenaline and cefuroxime, p=0.003: Fischer’s exact test).  Dose calculation errors of similar magnitude to injections, syrup and suspension were also observed with tablet formulation.

Conclusions: LASUCOM medical students lacked the basic knowledge of paediatric drug dose calculations but were willing to learn if the topic was formally taught. Drug dose calculations should be given a prominent consideration in the undergraduate medical curriculum in Nigeria.


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1. Bates DW, Cullen DJ, Laird N, Petersen LA, Small SD, Servi D, Laffel G, Sweitzer BJ, Shea BF, Hallisey R, et al. Incidence of adverse drug events and potential adverse drug events: implications for prevention. JAMA. 1995;274(1):29-34.

2. Lesar TS, Briceland LL, Stein DS. Factors related to errors in medication prescribing. JAMA. 1997;277:312-317.

3. Wheeler DW, Remoundos DD, Whittlestone KD, House TP, Menon DK. Calculation of drugs in solution: are medical students confuse by different means of expressing drug concentrations? Drug Saf. 2004;27(10):729-734.

4. Rolfe S, Harper NJ. Ability of hospital doctors to calculate doses. Br Med J. 1995;310:1173-1174.

5. Scrimshire JA. Safe use of lignocaine. Br Med J. 1989;298:1494.

6. Wheeler DW, Remoundos DD, Whittlestone KD, Palmer MI, Wheeler SJ, Ringrose TR, Menon DK. Doctors’ confusion over ratios and percentages in drug solutions: the case for standard labelling. J R Soc Med. 2004;97(8):380-383.

7. Oldridge GJ, Gray KM, McDermott LM, Kirkpatrick CM. Pilot study to determine the ability of health-care professionals to undertake drug dose calculations. Int Med J. 2004;34(6):316-319.

8. Oshikoya KA, Ojo OI. Medication errors in paediatric outpatient prescriptions in Nigeria. Niger Quart J Hosp Med. 2007;17:74-78.

9. Lack JA, Stuart-Taylor ME. Calculation of drug dosage and body surface area of children. Br J Anaesth 1997;78:601-605.

10. Wheeler SJ, Wheeler DW. Dose calculation and medication error-why are we still weakened by strength? Eur J Anaesthesiol. 2004;21:929-931.

11. Wheeler DW, Whittlestone KD, Salvador R, Wood DF, Johnston AJ, Smith HL, Menon DK. Influence of improved teaching on medical students’ acquisition and retention of drug administration skills. Br J Anaesth. 2006;96(1):48-52.

12. Parmar CM, Jadav SP. Teaching undergraduate students appropriate dose calculations in relation to intravenous infusion. Indian J Pharmacol. 2006;38:435-437.

13. Degnan BA, Murray LJ, Dunling CP, Whittlestone KD, Standley TD, Gupta AK, Wheeler DW. The effect of additional teaching on medical students’ drug administration skills in a simulated emergency scenario. Anaesthesia. 2006;61(12):1155-1160.

14. Wheeler DW, Carter JJ, Murray LJ, Degnan BA, Dunling CP, Salvador R, Menon DK, Gupta AK. The effect of drug concentration expression on epinephrine dosing errors: a randomized trial. Ann Intern Med. 2008;148(1):11-14.

15. Adams A, Duffield C. The value of drills in developing and maintaining numeracy skills in an undergraduate nursing programme. Nurs Educ Today. 1991;11:213-219.

16. Kozer E, Scolnik D, Jarvis A, Koren G. The effect of detection approaches on the reported incidence of tenfold error. Drug Saf. 2006;29(2):169-174.

17. Timothy SL. Errors in the use of medication dosage equations. Arch Pediatr Adolesc Med. 1998;152:340-344.

18. Potts MJ, Phelan KW. Deficiencies in calculation and applied math skills in paediatrics among primary care interns. Arch Paediatr Adolesc Med. 1996; 150: 748-752.

19. Bayne T, Bindler R. Medication calculation skills of registered nurses. J Cont Educ Nurs. 1988;19:258-262.

20. Durrieu G, Hurault C, Bongard V, Damase-Michel C, Montastruc JL. Perception of risk of adverse drug reactions by medical students: influence of a 1 year pharmacological course. Br J Clin Pharmacol. 2007;64(2):233-236.

21. GMC. Tomorrow’s Doctors. Recommendations on Undergraduate Medical Education. London: General Medical Council, 2003.

22. Tripathi KD. Essential of medical pharmacology. 5th ed. New Delhi, India: Jaypee Brothers Medical Publishers (P) Ltd; 2003.

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