Publication of Drug Interaction Unlikely to Impact Prescribing Patterns

Better strategies are needed to translate knowledge about DDIs
Better strategies are needed to translate knowledge about DDIs

Does publication of a serious drug-drug interaction (DDI) in a "high-profile" journal lower the concomitant use of the interacting medications? 

Researchers from the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, sought to answer this question in a new study published in the journal Clinical and Translational Science. 

The authors performed a quasi-experimental study using drug claims between 2000–2008 from a commercial health insurer (Clinformatics Data Mart, OptumInsight) to evaluate the trends in dispensing the following pairs of interacting drugs and control pairs:

  • ACE inhibitors + potassium-sparing diuretic
  • Digoxin + clarithromycin
  • Glyburide + cotrimoxazole

Interaction data on the above drug pairs were previously published in top-tier general medicine journals. The prepublication period was May 2000–March 2003 ending when the paper by Juurlink et al. was published. The authors assumed a minimum of 6 months for publication to have any effect on prescribing. The postpublication period was deemed October 2003–December 2008.

The data showed that ACE inhibitor + potassium-sparing diuretic use did not change post- vs. prepublication (P=0.11).  Compared to prepublication, digoxin + clarithromycin use decreased slightly postpublication (relative rate (RR) 0.9996, 95% CI: 0.9993–0.9998). 

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On the other hand, glyburide + cotrimoxazole use increased slightly post- vs. prepublication (RR 1.0220, 95% CI: 1.0187–1.0254). 

The findings point to "minimal to no measurable effect" in lowering the concomitant use. "We believe that better strategies are needed to translate knowledge about DDIs into clinical practice," stated lead author, Emily K. Acton. 

The authors point to clinicians' heavy reliance on computerized clinical decision support systems (CDS) as a possible reason for why there was so little impact after publication of the DDIs. They cite a study by Ridgely, et, al which discusses the excessive number of alerts in CDS systems, which results in alert fatigue and alerts constantly being overridden. "A crucial step in reducing drug-related adverse events may be to improve the overall quality and signal-to-noise ratio in DDI knowledge bases," the authors concluded.

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