Background Chronic hepatitis C management has changed tremendously with approval of direct acting antivirals (DAAs). DAAs provide a high sustained virological response with rare adverse effects. However, our healthcare system imposes constraints on prescriptions and dispensing due to rapid changes in guidelines and the high cost of DAAs. Hence treatments are only initiated in authorised centres with multidisciplinary meetings in which the pharmacist contributes to drug-drug interactions (DDIs) analysis and the choice of DAA.

Purpose The aim of the DDIs study was to prevent toxicity due to overdose or loss of DAA efficiency caused by DDIs.

Material and methods We analysed DDIs on the basis of standard treatment access forms sent to our hospital over a 2 month period. One or more DAA strategy proposals and patients’ regular therapy drugs were systematically submitted to the pharmacists to seek their advice. Hep-druginteractions.org database, as recommended by AFEF guidelines (French Association of Liver Study), Vidal monographs and analyses of the literature were methods used to identify and manage DDIs.

Results 43 prescriptions were analysed. Prescriptions for regular therapies contained, on average, 5 drugs corresponding to 125 different drugs. This represents 319 combinations between DAAs and regular drugs. Most of the combinations did not present a DDI (75%), 7 presented contraindications (2%) (involving statins (rosuvastatin, simvastatin), antiepileptics (primidone), antiretrovirals (efavirenz) and beta-2-agonists (salmeterol)). 60 combinations (19%) required patient monitoring and dose adjustment if clinically needed. Three adjustments of daclatasvir (1%) (2 reduced doses at 30 mg daily, 1 increased dose at 90 mg daily), 8 dose schedule optimisations (2.5%) (involving ledipasvir and proton pump inhibitor, resins) and 2 corticoid substitutions (0.5%) (fluticasone and budesonide by beclometasone) were advised. There were DDIs in 47% ombitasvir/paritaprevir/ritonavir, 40% simeprevir, 16% sofosbuvir/ledipasvir and 13% sofosbuvir/daclatasvir proposals.

Conclusion This study shows that 25% of combinations between DAAs and patients’ regular drugs had a DDI. As expected, because of its metabolism, the ombitasvir/paritaprevir/ritonavir association had more DDIs than the other DAAs. Increase in access treatment requests overload the pharmacist’s routine job. However, the pharmacist plays a key role in DDI management and participates in the choice of hepatitis C treatment.

References and/or Acknowledgements AFEF guidelines, June 2015

No conflict of interest.