IJPP 2003, 11: 217-223
© 2003 Int J Pharm Pract
Received May 10, 2003
Accepted September 30, 2003
ISSN 0961-7671

Faculty of Pharmacy, University of Manitoba, Canada

Ruby E. Grymonpre, professor
Meghan McKechnie, pharmacy student
Colin Briggs, professor

Correspondence: Dr Grymonpre, Faculty of Pharmacy, 50 Sifton Road, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
E-mail: grymonpr@ms.umanitoba.ca

Acknowledgments: The authors would like to acknowledge Manitoba pharmacists, the Manitoba Pharmacists’ Association, Manitoba Society of Pharmacists, Apotex Inc, Manitoba Health, and Canadian Institutes of Health Research for their support of the Manitoba Pharmaceutical Care project. This project also received a 2002 Summer Research Studentship supported by Apotex/PACE, Consumers Drug Mart, and Maria Stevenson, Herbal Consultant.

Original Papers

Community pharmacists' identification of natural health product/drug interactions in older persons

Ruby E. Grymonpre, Meghan McKechnie and Colin Briggs

Abstract
Objective To document the prevalence and significance of potential natural health products (NHPs)/prescribed drug interactions in a sample of older adults; to determine whether community pharmacists detected these drug interactions; and to characterise users and non-users of NHPs.

Setting The project involved 15 community pharmacists providing pharmaceutical care to 213 non-institutionalised older adults.

Methods The study was a subanalysis of a prospective, non-randomised, before-and-after trial of the provision of pharmaceutical care. Pharmacists documented each time medication-specific information or advice was provided to subjects. The numbers and types of NHPs that clients reported taking and the number of potentially significant NHP/prescribed drug interactions were determined. Whether pharmacists identified such drug interactions and made the necessary interventions was also documented.

Results Forty-two NHPs were reported 96 times by 49 (23%) clients, most commonly glucosamine (n =10), garlic (n =10), prune juice (n = 9), and Ginkgo biloba (n = 6). There was a total of 446 possible NHP/prescribed drug combinations in the 49 clients, of which 53 (12%) were considered to be of potential clinical significance. Of these 53 combinations, three pharmacists identified four (8%) potential interactions in three different patients. Although gender, mean age and number of reported medical conditions did not differ between users and non-users of NHPs, users reported taking fewer prescribed drugs compared with non-users (5.0 ± 3.2 vs 6.0 ± 2.9, respectively, P = 0.043) and more non-prescribed drugs (4.2 ± 2.5 vs 2.1 ± 2.0, respectively, P < 0.0001).

Conclusion The reported prevalence of NHP and the potential for NHP/prescribed drug interactions in our sample of older adults was high. Pharmacists providing pharmaceutical care did not commonly identify potentially significant NHP/prescribed drug interactions.