Science to Practice
Latest highlights on drug safety and efficacy

20.8.2026

In an unpublished report, we reviewed the medication profiles of 310 patients treated at the interface of hospital and primary care within a single healthcare organisation. The organisation has used the Inxbase drug–drug interaction database as part of clinical decision support (CDS) for more than a decade.

Polypharmacy was common

The patient population was demographically broad and balanced by sex. Medication burden varied substantially: the median number of medicines per patient was two, with a range from 0 to 32.

Polypharmacy, defined as the concurrent use of at least five medicines, was common: 105 patients (33.9%) met the polypharmacy criterion.

Few severe drug–drug interactions were observed after more than a decade of CDS use, suggesting that clinicians take the most serious interaction warnings into account when prescribing.

A clear difference between C- and D-level interactions

There was a substantial difference in the number of C- and D-level drug–drug interactions detected:

• 10 D-level interactions, where concomitant use should be avoided
• 141 C-level interactions, which can generally be managed, for example, through dose adjustments or monitoring

Among the D-level findings, no exact drug–drug pair recurred; the same interaction combination did not appear twice.

Tramadol occurred in three different D-level pairs: duloxetine–tramadol, mirabegron–tramadol and paroxetine–tramadol. These interactions lead to a diminished analgesic effect of tramadol.

Tinzaparin appeared in two D-level findings, each time combined with an oral anticoagulant – rivaroxaban or edoxaban. These findings likely reflected switching from parenteral to oral anticoagulation rather than a true interaction.

Among the C-level interactions, there was a high number of occurrences (19 in total) involving ondansetron or granisetron in combination with paracetamol.

What can the findings tell us about clinical decision support?

The occurrence of D-level interactions was relatively low compared with, for example, a nationwide survey conducted in Sweden (1), particularly when the anticoagulation findings, which likely represented treatment transitions rather than true interactions, were excluded.

This suggests that clinicians have taken D-level CDS warnings into account when prescribing.

Another lesson from this report is that clinicians tolerate C-level warnings, possibly by making dose adjustments and arranging the recommended monitoring for patients.

Learn more about how Medbase CDS helps healthcare professionals make safer, evidence-based medication decisions directly within clinical workflows.

News produced by Medbase Medical Team

References

1. Holm J, Eiermann B, Eliasson E, Mannheimer B. A limited number of prescribed drugs account for the great majority of drug-drug interactions. Eur J Clin Pharmacol. 2014 Nov;70(11):1375-83