gms | German Medical Science

19. Jahrestagung der Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie (GAA)

Gesellschaft für Arzneimittelforschung und Arzneimittelepidemiologie

22.11. - 23.11.2012, Jena

On the frequency of drug-drug interactions in ambulatory care

Zur Häufigkeit von Arzneimittel-Interaktions-Potenzialen in der ambulanten Versorgung

Meeting Abstract

Suche in Medline nach

  • Uwe Eichler - Wissenschaftliches Institut der AOK (WIdO), Berlin
  • Irene Langner - Wissenschaftliches Institut der AOK (WIdO), Berlin
  • Gisbert W. Selke - Wissenschaftliches Institut der AOK (WIdO), Berlin

Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie e.V. (GAA). 19. Jahrestagung der Gesellschaft für Arzneimittelanwendungsforschung und Arzneimittelepidemiologie. Jena, 22.-23.11.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. Doc12gaa15

doi: 10.3205/12gaa15, urn:nbn:de:0183-12gaa156

Veröffentlicht: 14. November 2012

© 2012 Eichler et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen ( Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.



Background: Polypharmacy has increasingly attained the focus of perception as a problem of drug therapy. Elderly patients, often miulti-morbid, are particularly affected. The physician’s challenge is to treat the individual illnesses according to the state of the art, while at the same time excluding uncontrolled drug-drug interactions, which could cause further illnesses, needing to be treated in turn. The problem is aggravated by patients receiving prescriptions from different physicians in uncoordinated ways. On the other hand, it has been pointed out that polypharmacy is not a problem per se, so merely looking at drug counts is not sufficient. Linking prescription data with pharmacologically based knowledge on interactions will yield a more realistic picture of the potential dangers of polypharmacy.

Materials and Methods: Nation-wide German data on prescriptions to AOK patients in the first quarter of 2012, and the Dosing interaction database.

Results: In total we have found 12.4 M cases of interactions with at least “moderate” severity (degree 3). Almost 2.3 M cases were classified as “severe”, almost 200 K as “contraindicated” (degree 5). The most frequently prescribed combination of degree 5 was clopidogrel and omeprazole (nearly 50 K cases). For the moderate interactions, a potential for increased antihypertensive effects was observed most frequently (nearly 650 K cases). The substances ramipril, acetylsalicylic acid (aspirin) and hydrochlorothiacide were most often involved in problematic combinations.

In total, 5.4 M patients were treated with problematic combinations. As might be expected, the number of such cases increases substantially with age. Up to 70 years, men are affected more often, afterwards women are (in absolute terms).

The talk presents the current state of an ongoing analysis.

Conclusions: A substantial share of hospital admissions both in Germany and internationally is associated with ADRs. Drug-drug interactions contribute substantially to these events, as can be seen from the number of prescriptions of contraindicated combinations. Even if interactions may be controlled through tight follow-up on lab values, there remains a relevant potential of jeopardising patients. Better coordination between physicians and increased attempts at reducing the number of active agents prescribed, or at least of the time span during which they are administered, can contribute to a noticeable improvement of quality in drug therapy.