What affects anticoagulation control in patients taking warfarin?
Source: British Journal of General Practice, Volume 59, Number 565, August 2009 , pp. 590-594(5)
Publisher: Royal College of General Practitioners
The ageing population is taking an increasing number of both prescribed and non-prescribed medication. Little is known of the potential for adverse drug reactions between these. Warfarin is a commonly prescribed medication, well known for its potential to cause serious adverse reactions in combination with many prescription medicines. It has been suggested that herbal medicines such as garlic, either as a dietary supplement or in cooking, may also interact with warfarin, resulting in poor international normalised ratio (INR) control.
To determine whether, for patients who take garlic as well as warfarin, the proportion of the INR tests in range is lower than in comparable patients who do not take garlic.
Design of the study:
Retrospective study of patients taking prescribed warfarin.
Primary care practices in Somerset and Devon.
Three controls (not taking garlic) matched for age, sex, and general practice were compared with each patient self-reporting taking garlic as a supplement. INR results were assessed for the preceding 12 months. Potentially confounding factors were considered, for example diabetes mellitus; all prescribed medication; any bleeding episodes.
No evidence was found to suggest that garlic consumption either as a supplement or in cooking is associated with more frequent haemorrhagic complications or less control of INR. Poor INR control may, however, be associated with taking larger numbers of prescription medicines, particularly during prescription changes.
Further research would be warranted into whether increased INR monitoring is needed when drug changes are made. These data render clinically significant interactions between warfarin and garlic intake unlikely.
Document Type: Research Article
Affiliations: 1: East Somerset Research Consortium, Westlake Surgery, West Coker, Somerset BA22 9AH 2: Peninsula Medical School, Universities of Exeter and Plymouth, Exeter 3: Research Design Service, National Institute for Health Research, Taunton 4: Taunton and Somerset R&D Consortium, Taunton and Somerset NHS Foundation Trust, Taunton 5: East Somerset Research Consortium, West Coker
Publication date: 2009-08-01
- The British Journal of General Practice (BJGP) is an international journal publishing articles of interest to family practitioners and primary care researchers worldwide. The journal's 2012 Impact Factor is 2.034, making it one of the world's most highly cited journals of general practice and primary health care.
Members of the Royal College of General Practitioners receive complementary access to recent issues of the BJGP. Access is via the members' login area using RCGP membership details. All users can find access help for current and archive articles at Accessing BJGP.
- Editorial Board
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Information for Advertisers
- BJGP Current Issue
- BJGP Archive
- BJGP Discussion Forum
- ingentaconnect is not responsible for the content or availability of external websites