gms | German Medical Science

21st Annual Meeting of the German Drug Utilisation Research Group (GAA), 9th German "Pharmakovigilanztag"

Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie

20.11.-21.11.2014, Bonn

Potential drug-drug interactions in the elderly: prescribing patterns of German physicians

Meeting Abstract

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Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie e.V. (GAA). 21. Jahrestagung der Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie, 9. Deutscher Pharmakovigilanztag. Bonn, 20.-21.11.2014. Düsseldorf: German Medical Science GMS Publishing House; 2014. Doc14gaa24

doi: 10.3205/14gaa24, urn:nbn:de:0183-14gaa249

Published: November 18, 2014

© 2014 Langner et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Background: Drug-drug interactions are held responsible for a substantial percentage of hospitalisations in the elderly. Interventions can reduce inappropriate prescribing, while clinical outcomes remain uncertain.

Materials and Methods: Drug prescription data for the last quarter of 2013 for the largest German group of statutory health care funds covering about 35% of the population, were analysed, permitting attribution of prescriptions to (anonymous) individuals over the age of 65. Using ATC and DDD methodology, likely cases of concurrent intake of drug combinations were identified and matched against a large database (Haefeli) of combinations with known potential (of at least moderate severity) for interaction. Likely cases of opportune interactions were excluded.

Results:

  • 46% of AOK patients aged 65+ receiving medication during the 4th quarter of 2013 were subject to at least one potential drug-drug interaction of at least moderate degree, 0.8% were subject to contraindicated combinations.
  • Substances for treatment of cardiovascular conditions dominate the ranking lists; clopidogrel/omeprazole was the most prescribed contraindicated combination.
  • In 80% of cases, both of the potentially interacting drugs were prescribed by the same physician.
  • No strong correlation of high share of potential interactions with high DU90, which should be an indicator for less knowledge of interaction spectrum of drugs
  • Cardiologists, GPs, rheumatologists and internists had the biggest share of prescriptions that contributed to potential interactions (median for all physicians: 21%). Where two different physicians had prescribed interacting drugs, GPs, orthopaedists, ophthalmologists, neurologists and cardiologists were involved most.

Conclusion: Interactions may be exacerbated by, but are not primarily due to lack of communication between different prescribers. Differences between individual physicians show that differentiated interventions to reduce potentially problematic drug-drug interactions are needed, including changes in academic education.


References

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Becker ML, Kallewaard M, Caspers PW, Visser LE, Leufkens HG, Stricker BH. Hospitalisations and emergency department visits due to drug-drug interactions: a literature review. Pharmacoepidemiol Drug Saf. 2006; 16: 641–51.
2.
Patterson SM, Hughes C, Kerse N, Cardwell CR, Bradley MC. Interventions to improve the appropriate use of polypharmacy for older people. Cochrane Database Syst Rev. 2012;(5):CD008165.