. 2016 Jan 12;5:1–10. doi: 10.2147/IPRP.S95733

Table 1.

Description for the identified published studies

Study	Country	Type of study	Duration	Setting	Outcomes
Bohand et al²³	France	Prospective, direct observation by pharmacists and nurses to detect unit dose DEs	(2 months) March–April 2007	Central pharmacy, unit dose for cardiovascular ward (30 beds) of the 354 bed Percy military hospital	179 dispensing errors were detected from 7,249 units dose filled; the most common dispensing error types were incorrect dose 57 (31.8%) and omission 54 (30.2%). 86.6% of the DEs were detected by pharmacists during final check.
James et al²⁰	UK	Retrospective, analyzed prevented and unprevented DEs reported to UK dispensing error analysis scheme (UKDEAS)	(3 months) September–December 2005	17 acute hospitals in Wales	334 dispensing errors reported; 35 unprevented DEs and 339 prevented DEs. 157 (54%) of prevented DEs and 13 (37%) of unprevented DEs were labeling errors, for example, labeling wrong drug (prevented, n=15; unprevented n=6). Dispensed wrong drug strength (prevented, n=46; unprevented n=2). Look-alike/sound-alike, high workload, and inexperienced staff were the most commonly contributed factors reported.
Irwin et al²⁶	UK	Retrospective, analyzed incident reports	(5 years) July 2005–March 2010	25 Scottish hospitals	573 dispensing errors reported; the most frequent dispensing error types were dispensed wrong drug 110 (19.2%) and dispensed strength 96 (16.8%). The most frequent distributed factor reported were the medicines’ similarity in name, high workload, and inexperienced staff.
Bonifacio Neto et al²²	Brazil	Prospective, direct observation	(2 months) July–August 2011	Central pharmacy, unit dose for cardiovascular and pulmonary ward (36 beds) of the 280 bed university hospital	1,611 dispensing errors were detected from 4,837 dispensed items; dispensed medicines without the described pharmaceutical form was the most common error (n=1,396, 86.6%).
James et al²¹	UK	Retrospective, analyzed incident reports	(2 years) January 2003–December 2004	20 Welsh NHS hospital pharmacies	1,005 dispensing errors reported to UKDEAS; the most frequent errors were dispensed incorrect strength 241 (24%), incorrect drug 168 (17%), and wrong form 134 (13%). The most common medicine involved in DEs was insulin (n=34). Look-alike/sound-alike, high workload, low staffing, and inexperienced staff were the most commonly contributed factors reported.
Beso et al²⁵	UK	Prospective by identified DEs in the final check, then interview with pharmacy staff who made the error to explore the causes	(2 weeks) June 17–28, 2002	Teaching hospital in London (450 beds)	The rate of dispensing errors was 2.7% (130/4,849); dispensed wrong quantity was the most common errors (n=38, 29%), then labeling wrong quantity (n=18, 13.8%). High workload, low staff, interruptions, look-alike/sound-alike, and lack of knowledge about the availability of different medicines and formulation were the most common reported contribution factors.
Anacleto et al²⁹	Brazil	Prospective, direct observation	(21 days) September 2002	Unit dose in Belo Horizonte hospital pharmacy (286 beds)	719 dispensing errors were detected from 2,143 dispensed items; the most frequent DEs were dose omission (n=412, 57.3%) and dispensing wrong quantity (n=91, 12.7%).
Rolland³⁴	USA	Retrospective, analyzed incident reports	(4 years) October 1997–September 2001	Eight different sections at Central Arkansas Veteran’s Healthcare System	82 dispensing errors were reported; dispensing wrong medicines (n=31, 37.8%), dispensing to wrong patient (n=24, 29.2%), and dispensing wrong dose (n=21, 25.6%) were the most common DEs types.
Seifert and Jacobitz³²	USA	Retrospective, chart review	(35 months) January 1999–November 2002	All drug exposures reported to Midwest regional poison control centers	40 dispensing errors reported among of 77,992 drug exposures reports; 20 DEs (50%) were substitution errors and 17 DEs (42.5%) were labeling errors.
Rissato and Romano-Lieber³⁰	Brazil	Prospective, direct observation	(16 days) January 4–19, 2010	Central pharmacy, unit dose for surgical ward (30 beds) of university hospital (104 beds)	61 dispensing errors were observed from 1,963 prescribed drug items; the most frequent DEs were dose omission 14 (23%) and dispensed nonprescribed medication.
Cina et al²⁴	USA	Prospective, direct observation	(7 months) February–August 2003	Central pharmacy, unit dose at tertiary academic medical center (725 beds)	5,075 (3.6%) dispensing errors were observed from 140,755 doses; 4,016 DEs prevented and 1,059 were unprevented DEs. The most frequent dispensing error types were dispensing wrong quantity (n=2,978, 59%), wrong strength (n=571, 11%), and wrong drug (n=554, 11%).
Costa et al²⁸	Brazil	Prospective, direct observation	(27 days) 25 August–20 September	Central pharmacy, unit dose at pediatric hospital (96 beds)	300 (11.5%) dispensing errors were observed from 2,620 observed doses. 43.3% missing dose, 25% dose added, and 13.3% omission.
Anto et al³¹	UK	Retrospective, analyzed incident reports	(4 years) January 2005–December 2008	Two main pharmacies at NHS Foundation Hospital Trust in London (1,200 beds)	911 prevented and unprevented dispensing errors; the most frequent DEs were dispensing wrong strength 13.4% (n=122), dispensing wrong drug 7.13% (n=65), and dispensing wrong form 2.6%.
Bohand et al²⁷	France	Prospective, direct observation	(8 months) April–December 2006	Central pharmacy, unit dose Percy military hospital (354 beds)	706 dispensing errors were observed from 88,609 doses; the most dispensing error types were wrong dose (n=265, 37.5%) and omission dose (n=186, 26.3%).
Anto et al³³	UK	Prospective, face-to-face interviews	(3 months) September–November 2008	A 1,200 bed NHS Foundation Trust	42 labeling incidents were recorded. The most common contributed factors were: high workload, limited staff, lack of knowledge, lack of concentration, hurrying through tasks, and illegible handwriting.

Abbreviations: DE, dispending error; NHS, National Health Service.