4CPS-097 Cobicistat interactions with chronic treatments

Background Cobicistat is used in clinical practice as a pharmacokinetic enhancer of protease and/or integrase inhibitors. Nevertheless, the mechanism by which this occurs (metabolism inhibition) makes cobicistat-containing HIV regimens very prone to interact with chronic treatments, which triggers toxicity. Purpose To reconcile HIV treatments containing cobicistat and to analyse the interactions with the chronic treatment. Material and methods Patients attending the outpatient pharmacy clinic between January and September 2018 with a regimen containing cobicistat were included. During the dispensation of their HIV medication, patients’ treatment was reconciliated by two methods: pharmacy interview and consultation of the prescribed medication in the primary records. The interaction between the cobicistat and the patients’ chronic treatment was checked in drugs.com. In this website interactions are classified as major, moderate, minor and non-interaction. Results Eight-hundred and forty-two treatments were reconciliated (patients: 47.9±11.5 years old; 82.4% male). Twenty-eight different HIV regimens were identified, the most frequent being the one containing Genvoya (cobicistat, elvitegravir, emtricitabine, tenofovir alafenamide) (68.4%).Two-hundred and forty different chronic drugs were prescribed (2.2±2.4 drugs per patient). Twenty-one drugs were classified to have a major interaction with cobicistat, 40 a moderate interaction, five minor, 147 did not have any interaction registered in drugs.com and 27 drugs did not appear in this web. Pharmacists made 87 interventions with 35 different drugs. The most frequent were inhaled budesonide (12) and nasal fluticasone (11). Forty-four (51%) of the pharmaceutical interventions did not need the physician’s approval (17 to interrupt chronic treatments, 13 to change treatments, 12 to monitor and one to change dose). The rest (43) required physician approval and these consisted of more varied actions, highlighting six changes in the HIV regimen to eliminate cobicistat. We registered possible/probable toxicities related to the inhibition of metabolism due to cobicistat in eight patients. Conclusion Pharmacist reconciliation detects numerous potential interactions. Pharmacist intervention helped to modify several treatments and make treatments safer. References and/or acknowledgements None. No conflict of interest.