Wrongly Prescribed Half Tablets in a Swiss University Hospital


Background: Prescription of 1/2 tablets is a widespread practice, mainly to achieve dose flexibility and to facilitate swallowing. However, tablet splitting includes several disadvantages, like destruction of galenic formulation, stability problems, and unequal amount of active ingredient that may reduce effectiveness or result in a greater risk of toxicity. Objective: To assess the rate of wrongly prescribed 1/2 tablets in discharge prescriptions at the University Hospital in Basel (UHBS, 600 beds) and to evaluate its consequences for community pharmacists. Setting: Discharge prescriptions written between January 1st and December 31st 2011 and containing the term “1/2” were extracted from the electronic patients’ data management system of the UHBS. Presence of a score line and suitability for splitting were retrieved from two official sources of drug information. Main Outcome Measure: Wrong prescription was assigned for tablets with no score line or not suitable for dose splitting. Results: Of the 36,751 discharge prescriptions that were recorded in 2011 at the UHBS, 3724 (10.1%) contained at least one prescription item with the term “1/2”. The recipient patients were on average 72.9 ± 14.8 years old (median 76 years), 50.9% were women. Of the 4517 analysed items, 49% had a corresponding lower dosage strength available on the market, making splitting unnecessary. Rate of wrongly prescribed 1/2 tablets reached 16.4% (2.8% of all prescriptions) and concerned predominantly unscored tablets. When the lack of information on splitting suitability (5.6%) and on score lines (0.5%) was taken into account, the rate reached 22.4%. Half of all wrong prescriptions could be assigned to 14 different products that were prescribed with an overall rate between 3.1 and 0.2%. Quetiapine (Seroquel?) at all strengths was the most often wrongly prescribed tablet to split (3.1%; no score line), followed by atorvastatin (Sortis?) at all strengths (1.3%; no score line) and oxazepam (Seresta?) 15 mg (1.2%; with decorative score line). Conclusion: Prescribing of 1/2 tablets is common and concerns every 10th discharge prescriptions. It represents a pharmaceutical care issue, since in almost every second case, an identical drug with half the dosage strength is commercially available and a substitution could be offered by the community pharmacist. Further, one out of 5 prescribed 1/2 tablets is wrong or untraceable in the official sources of drug information and represents a safety issue. In all cases, time consuming and costly clarifications must be undertaken, ultimately the physician must be consulted, in order to modify the prescription or to dispense the prescribed 1/2 tablets as off-label use. If splitting is allowed, the patient’s cognitive and physical capacities have to be clarified and appropriate aids have to be offered, e.g. a pill splitter, in order to insure the safe use of the drug.

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I. Arnet, M. Moos and K. Hersberger, "Wrongly Prescribed Half Tablets in a Swiss University Hospital," International Journal of Clinical Medicine, Vol. 3 No. 7, 2012, pp. 637-643. doi: 10.4236/ijcm.2012.37114.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] B. Dean, N. Barber and M. Schachter, “What Is a Prescribing Error?” Quality in Health Care, Vol. 9, 2000, pp. 232-237. doi:10.1136/qhc.9.4.232
[2] R. Quinzler, C. Gasse, A. Schneider, P. Kaufmann-Kolle, J. Szecsenyi and W. Haefeli, “The Frequency of Inappropriate Tablet Splitting in Primary Care,” European Journal of Clinical Pharmacology, Vol. 62, No. 12, 2006, pp. 1065-1073. doi:10.1007/s00228-006-0202-3
[3] N. Rodenhuis, P. De Smet and D. Barends, “The Rationale of Scored Tablets as Dosage Form,” European Journal of Pharmaceutical Sciences, Vol. 21, No. 2-3, 2004, pp. 305-308. doi:10.1016/j.ejps.2003.10.018
[4] R. Quinzler and W. Haefeli, “Tabletten Teilen,” Therapeutische Umschau, Vol. 63, 2006, pp. 441-447. doi:10.1024/0040-5930.63.6.441
[5] R. Quinzler, W. Haefeli, “Zerkleinern von Tabletten,” TMJ, 2008, pp. 44-47.
[6] E. van Santen, D. Barends and H. Frijlink, “Breaking of Scored Tablets: A Review,” European Journal of Pharmaceutics and Biopharmaceutics, Vol. 53, No. 2, 2002, pp. 139-145. doi:10.1016/S0939-6411(01)00228-4
[7] P. Gupta and K. Gupta, “Broken Tablets: Does the Sum of the Parts Equal the Whole?” American Journal of Health-System Pharmacy, Vol. 45, No. 7, 1988, p. 1498.
[8] Australian Pharmaceutical Advisory Council, “Guidelines for Medi-cation Management in Residential Aged Care Facilities,” 3rd Edition, Commonwealth of Australia, 2002.
[9] J. G. Schier, M. A. Howland, R. S. Hoffman and L. S. Nelson, “Fatality from Administration of Labetalol and Crushed Extended-Release Nifedipine,” Annals of Pharmacotherapy, Vol. 37, No. 10, 2003, pp. 1420-1423. doi:10.1345/aph.1D091
[10] “Summary of Product Information of Puri-Nethol? Tablets 50 mg,” 2012. www.compendium.ch
[11] D. Bates, D. J. Cullen, N. Laird, L. Petersen, S. Small, D. Servi, G. Laffel, B. Sweitzer, B. Shea and R. Hallisey, “Incidence of Adverse Drug Events and Potential Adverse Drug Events: Implications for Prevention,” Journal of American Medical Association, Vol. 274, No. 1, 1995, pp. 29-34. doi:10.1001/jama.274.1.29
[12] J. K. Aronson, “Medica-tion Errors: Definitions and Classification,” British Journal of Clinical Pharmacology, Vol. 67, No. 6, 2009, pp. 599-604. doi:10.1111/j.1365-2125.2009.03415.x
[13] P. J. Lewis, T. Dornan, D. Taylor, M. P. Tully, V. Wass and D. M. Ashcroft, “Prevalence, Incidence and Nature of Prescribing Errors in Hospital Inpatients: A Systematic Review,” Drug Safety, Vol. 32, 2009, pp. 379-389. doi:10.2165/00002018-200932050-00002
[14] American Society of Health-System Pharmacists, “ASHP Standard Definition of a Medication Error,” American Journal of Hospital Pharmacy, Vol. 39, No. 2, 1982, p. 321.
[15] T. Lesar, L. Briceland and D. Stein, “Factors Related to Er-rors in Medication Prescribing,” Journal of the American Medical Association, Vol. 277, 1997, pp. 312-317. doi:10.1001/jama.277.4.312
[16] E. Arques-Armoiry, D. Cabelguenne, C. Stamm, A. Janoly-Dumenil, I. Gros-set-Grange, N. Vantard, P. Maire and B. Charpiat, “Most Frequent Drug-Related Events Detected by Pharmacists during Prescription Analysis in a University Hospital,” La Revue de Médecine Interne, Vol. 31, No. 12, 2010, pp. 804-811. doi:10.1016/j.revmed.2010.08.001
[17] Arzneimittelkompendium der Schweiz Online, 2012. www.compendium.ch
[18] D. Bornand, “Zerm?rserbar-keit und Verabreichungshinweise von Tabletten,” 2008. www.spitalpharmazie-basel.ch/dienstleistungen/pdf/Zermoerserbarkeit_Tabletten.pdf
[19] Anonymous, “Teilbarkeit von Tabletten und Filmtabletten,” Swissmedic, Merkblatt, 2004.
[20] R. Quinzler, S. Schmitt, M. Pritsch, J. Kalt-schmidt and W. E. Haefeli, “Substantial Reduction of Inappropriate Tablet Splitting with Computerised Decision Support: A Prospective Intervention Study Assessing Potential Benefit and Harm,” BMC Medical Informatics and Decision Making, Vol. 9, 2009, p. 30.
[21] T. Lesar, L. L. Briceland, K. Delcoure, J. Parmalee, V. Masta-Gornic and H. Pohl, “Medication Prescribing Errors in a Teaching Hospital,” Journal of the American Medical Association, Vol. 263, 1990, pp. 2329-2334. doi:10.1001/jama.263.17.2329
[22] N. Drewett, “Stop Regular Medicines Error,” Journal of Pharmacy Practice, Vol. 8, 1998, pp. 193-196.
[23] S. Dobrzanski, I. Hammond, G. Khan and H. Holdsworth, “The Nature of Hospital Prescribing Errors,” British Journal of Clinical Governance, Vol. 7, No. 3, 2002, pp. 187-193. doi:10.1108/14664100210438271
[24] S. O. Delgado, P. J. Nicolás, L. I. Martínez, F. A. Serrano, J. L. Anoz and C. F. Fernández, “Reconciliation Errors at Admission and Departure in Old and Polymedicated Patients. Prospective, Multicenter Randomized Study,” Medicina Clínica, Vol. 133, 2009, pp. 741-744.
[25] G. Schumock, A. Guenette, T. Keys and R. Hutchinson, “Prescribing Errors for Patients about to Be Discharged from a University Teaching Hospital,” American Journal of Hospital Pharmacy, Vol. 51, No. 18, 1994, pp. 2288- 2290.
[26] K. B. Johnson, J. K. Butta, P. K. Donohue, D. J. Glenn and N. A. Holtzman, “Discharging Patients with Prescriptions Instead of Me-dications: Sequelae in a Teaching Hospital,” Pediatrics, Vol. 97, No. 4, 1996, pp. 481-485.
[27] R. Shawahna and Nisar-Ur-Rahman, “Prescribing Errors Involved Splitting of Tablets: A Two-Hospital Case Analysis,” Pakistan Journal of Medical and Health Sciences, Vol. 2, 2008, pp. 54-58.
[28] M. Rupp, M. DeYoung and S. Schondel-meyer, “Prescribing Problems and Pharmacist Interventions in Community Practice,” Medical Care, Vol. 30, No. 10, 1992, pp. 926-940. doi:10.1097/00005650-199210000-00005
[29] I. Arnet and K. Hersberger, “Misleading Score-Lines on Tablets: Facilitated Intake or Fractional Dosing?” Swiss Med Weekly, Vol. 140, 2010, pp. 105-110.
[30] J. Bachynsky, C. Wiens and K. Melnychuk, “The Practice of Splitting Tablets: Cost and Therapeutic Aspects,” PharmacoEconomics, Vol. 20, 2002, pp. 339-346. doi:10.2165/00019053-200220050-00005
[31] R. S. Stafford and D. C. Radley, “The Potential of Pill Splitting to Achieve Cost Savings,” American Journal of Managed Care, Vol. 8, 2002, pp. 706-712.
[32] Royal Pharma-ceutical Society, “Guidance on the Pharmaceutical Issues When Crushing, Opening or Splitting Oral Dosage Forms,” 2011. www.rpharms.com/pharmacy-practice-resource/specials.asp
[33] A. Maher, M. Maglione, S. Bagley, M. Suttorp, J. Hu, B. Ewing, Z. Wang, M. Timmer, D. Sultzer and P. Shekelle, “Efficacy and Comparative Effectiveness of Atypical Antipsychotic Medications for Off-Label Uses in Adults: A Systematic Review and Meta-Analysis,” Journal of the American Medical Association, Vol. 306, 2011, pp. 1359- 1369. doi:10.1001/jama.2011.1360
[34] J. Devlin, R. Roberts, J. Fong, Y. Skrobik, R. Riker, N. Hill, T. Robbins and E. Garpestad, “Efficacy and Safety of Quetiapine in Critically Ill Patients with Delirium: A Prospective, Multicenter, Randomized, Double-Blind, Placebo-Controlled Pilot Study,” Critical Care Medicine, Vol. 38, No. 2, 2010, pp. 419-427. doi:10.1097/CCM.0b013e3181b9e302
[35] B. Maneeton, N. Maneeton and M. Srisurapanont, “An Open-Label Study of Quetiapine for Delirium,” Journal of the Medical Association of Thailand, Vol. 90, 2007, pp. 2158-2163.
[36] C.-U. Pae, S.-J. Lee, C.-U. Lee, C. Lee and I.-H. Paik, “A Pilot Trial of Quetiapine for the Treatment of Patients with Delirium,” Human Psycho-pharmacology, Vol. 19, No. 2, 2004, pp. 125-127. doi:10.1002/hup.559
[37] Y. Sasaki, T. Matsuyama, S. Inoue, T. Sunami, T. Inoue, K. Denda and T. Koyama, “A Prospective, Open-Label, Flexible-Dose Study of Quetia-pine in the Treatment of Delirium,” Journal of Clinical Psychiatry, Vol. 64, 2003, pp. 1316-1321. doi:10.4088/JCP.v64n1106
[38] M. Onor, M. Saina and E. Aguglia, “Efficacy and Tolerability of Quetiapine in the Treatment of Behavioral and Psychological Symptoms of Dementia,” American Journal of Alzheimer’s Disease & Other Dementias, Vol. 21, No. 6, 2007, pp. 448-453. doi:10.1177/1533317506294775

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