Dose omissions in hospitalized patients in a UK hospital: an analysis of the relative contribution of adverse drug reactions

Drug Saf. 2012 Aug 1;35(8):677-83. doi: 10.1007/BF03261964.


Background: The omission of charted (prescribed) doses for hospitalized patients is an important problem in the UK. Inappropriate drug omission can clearly lead to harm from lack of therapeutic effect. However, healthcare professionals administering medicines may decide that omission of a dose is appropriate in certain circumstances, e.g. when patients show signs of a possible adverse drug reaction (ADR).

Objective: The aim of this study was to characterize dose omissions to understand the factors that influence non-administration of therapy and to determine the proportion of doses that are appropriately omitted due to ADRs.

Methods: We used data from a bespoke hospital-wide electronic prescribing and administration system at University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK. We extracted data on 6.01 million drug administrations during 2010 and then randomly selected four 7-day periods, concentrating on doses that were charted but not given. Omitted medicines were counted if either there was a charted 'non-administration' (i.e. an active acknowledgement of the omitted dose) or there was no charting of that dose (i.e. no record of either administration or omission). Paused medicines were not counted. When a dose was omitted, staff indicated the reasons for non-administration using codes ('hard coded') or free text in the electronic system. We used both to compare the contribution of different factors, including ADRs, to the total rates of dose omissions.

Results: In the four 7-day periods analysed, 60 763 (12.4%) of the 491 894 charted doses were omitted. The most common code was 'patient refused drug' (45.4%). Only 1.6% of doses were omitted for reasons of patient safety, of which 4 in 1000 omissions were coded as directly due to an ADR.

Conclusions: Measures to improve the quality of care should seek to reduce dose omissions, but in some cases omission may be rational. Electronic medication administration records allow for detailed analysis of decisions made by healthcare professionals at the point of administration. While dose omissions related to ADRs are uncommon, they are important both for patient safety and for therapeutic decision making.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adverse Drug Reaction Reporting Systems*
  • Drug Dosage Calculations
  • Electronic Prescribing / statistics & numerical data
  • Hospitalization*
  • Humans
  • Medication Errors*
  • Medication Systems, Hospital / statistics & numerical data*
  • Patient Safety / statistics & numerical data*
  • Pharmaceutical Preparations / administration & dosage*
  • United Kingdom


  • Pharmaceutical Preparations