Background Introduction of direct acting antivirals (DAA) followed a multidisciplinary team meeting (MDTM), including a pharmacist who analyses potential drug interactions (DI) between recommended DAA and concomitant medications. New publications describing DI regularly appear but few data exist about the consequences of these interactions in practice.

Purpose To better define the consequences of DI in practice, we analysed and assessed their impact in terms of pharmaceutical interventions (PI) proposed, differentiated according to an impact score (IS).

Material and methods Patient characteristics and concomitant medications were provided by the MDTM physician coordinator. DI analysis (DIA) with recommended DAA was systematically performed according to these sources: summary of product characteristics, University of Liverpool hepatitis DI website (hep-druginteractions.org), scientific literature and pharmacovigilance alerts. Significant DI were subject to PI delivered to the MDTM physician coordinator who relayed them to the patient’s prescribing physician.

Over 5 months, this retrospective study analysed DI of patients with at least one DAA recommended and one concomitant medicine, identified by the Anatomical Therapeutic Chemical (ATC) classification. Resulting PI were ranked by IS.

Results Among 486 patients who presented to the MDTM, 239 (49%) were the subject of DIA: they accounted for 758 concomitant medications (average of 3), leading to 2034 DIA.

257 PI (13% of DIA) were proposed concerning 30% of the patients who presented (145), mainly infected with genotype 1 virus (68%), then 4 (14%), 3 (12%) and 2 (6%). Half of the PI were for 3 ATC classes: J05 ‘Antivirals for systemic use’ (antiretrovirals exclusively: 21%), A02 ‘Drugs for acid related disorders’ (proton pump inhibitors exclusively: 14%) and C07 ‘Beta blocking agents’ (14%).

64% of PI suggested clinical (74) or biological monitoring (90): IS1;

26% of PI suggested dose (34) or administration adjustment (32): IS2; and

10% of PI (27) suggested substitution or discontinuation of concomitant medicine or DAA: IS3.

These results underestimate the actual number of important impact DI (IS3), excluding PI orally proposed during the MDTM leading to the choice of specific DAA.

Conclusion DAA’s PI clinically or biologically relevant were numerous (at least 30% of patients); one-third (36%) had direct impact on the patient’s drug therapy (PI of IS2 and IS3). DIA of DAA is effective for patient management optimisation.

This study could be completed by assessment of PI acceptability by prescribers.

No conflict of interest.