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. 1999 Jun;47(6):689-93.
doi: 10.1046/j.1365-2125.1999.00957.x.

Signalling possible drug-drug interactions in a spontaneous reporting system: delay of withdrawal bleeding during concomitant use of oral contraceptives and itraconazole

E P Van Puijenbroek  1 , A C Egberts, R H Meyboom, H G Leufkens
Affiliations

Signalling possible drug-drug interactions in a spontaneous reporting system: delay of withdrawal bleeding during concomitant use of oral contraceptives and itraconazole

E P Van Puijenbroek et al. Br J Clin Pharmacol. 1999 Jun.

Abstract

Aims: In spontaneous adverse drug reaction reporting systems, there is a growing need for methods facilitating the automated detection of signals concerning possible adverse drug reactions. In addition, special attention is needed for the detection of adverse drug reactions resulting from possible drug-drug interactions. We describe a method for detecting possible drug-drug interactions using logistic regression analysis to calculate ADR reporting odds ratios.

Methods: To illustrate this method, we analysed the adverse drug reaction 'delayed withdrawal bleeding' resulting from a possible interaction between itraconazole and oral contraceptives in reports received by the Netherlands Pharmacovigilance Foundation LAREB between 1991 and 1998.

Results: In total 5,503 reports were included in the study. The odds ratio, adjusted for year of reporting, age and source of the reports, for a delayed withdrawal bleeding in women who used both drugs concomitantly compared with women who used neither oral contraceptives, nor itraconazole, was 85 (95% CI: 32-230).

Conclusions: Since spontaneous reporting systems can only generate signals concerning possible relationships, this association needs to be analysed by other methods in more detail in order to determine the real strength of the relationship. This approach might be a promising tool for the development of procedures for automated detection of possible drug-drug interactions in spontaneous reporting systems.

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Figures

Figure 1
Figure 1
Two by two table used for the calculation of ADR reporting odds ratios
See this image and copyright information in PMC

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