Interaction alerts: A comparison of classifications and recommendations for clinical management between Janusmed and three other knowledge resources

Classifications of drug interaction alerts differ between knowledge resources, but agreement regarding recommendations for clinical management is less explored. Starting from the medication lists of 274 older patients with ≥2 drugs, all unique drug pairs that triggered a clinically significant interaction alert in Janusmed were included: 100 Category C (manageable by, e.g. dose adjustment) and nine Category D interactions (should be avoided). Out of 109 C/D alerts in Janusmed, 89 (82%), 75 (69%) and 45 (41%) drug pairs triggered an alert of similar clinical significance in Lexicomp, Micromedex® and Stockley's Drug Interactions/Checker (Stockley), respectively. Eight (7%), 20 (18%) and 10 (9%) drug pairs did not trigger any alert in these resources. For 81 (74%), 81 (74%) and 94 (86%) drug pairs, Lexicomp, Micromedex and Stockley provided at least one recommendation for clinical management similar to those provided by Janusmed. For 16 (15%), 9 (8%) and 21 (19%) drug pairs, these resources provided recommendation(s) entirely in agreement with Janusmed. Although many drug pairs elicit alerts of similar significance, and partly concordant recommendations, a non-negligible proportion do not. The findings encourage medical/pharmaceutical reflection by prescribing clinicians and dispensing pharmacists; recommendations provided by knowledge resources vary considerably and cannot be considered definite.