Büsch K [1,2], Nystedt A , Baartz M , Kövamees J , Söderholm J [1,2]
Affiliates:  AbbVie AB, Stockholm, Sweden.  Karolinska Insitutet, Stockholm, Sweden.  Center for Communicable Disease Control, Norrbotten County Council, Sweden.  AbbVie Pty Ltd, Sydney, Australia.
Since 2014, several highly effective interferon-free treatment options have become available for chronic hepatitis C (CHC) patients. The overall medication use in the CHC cohort has previously been describe to be greater than in an equivalent general population comparator cohort, and polypharmacy could potentially be an issues due to potential drug-drug interactions (DDI). The aim of this nationwide registry study was to describe the usage of prescribed drugs in Swedish CHC patients.
Patients were identified for CHC (B18.2) according to ICD-10 in the inpatient (1997-2013) and non-primary outpatient care (2001–2013) in the nationwide Swedish Patient Register. Treatment information was obtained using ATC codes in the prescribed drug register (2005-2013), which covers all dispensed prescriptions in Sweden. The DDI profiles for Harvoni or Viekirax/Exviera were investigated using the HEP Drug iChart (University of Liverpool, UK)
In 2013, 34,633 prevalent CHC patients were living in Sweden, of which 85% (n=29,266) dispensed at least one prescribed treatment (mean number or substance prescriptions: 37 in CHC patients vs. 14 in matched general population comparators). Of those treated, 12% (n=3,401) received 1 treatment, 11% (n=3,241) 2, 10% (n=2,812) 3, 9% (n=2,569) 4, and 59% (n=17,243) patients dispensed 5 or more different treatments during 2013. Paracetamol and omeprazole were the most commonly prescribed substances. With regard to potential DDIs, if the 947 CHC patients that were treated for their CHC in 2013 would instead be treated using either Harvoni or Viekirax/Exviera in 2016, the DDI profile would have been good for both treatments. I.e. out of the most commonly used 75 products in these patients, none would have been classified as “do not coadministered” when using the Liverpool HEP iChart.
In line with previous findings, polypharmacy were common in the Swedish CHC cohort in 2013. This could potentially result in DDI when treating CHC if potential interactions with concomitant medications are not adequately investigated and appropriate adjustments undertaken to minimize risk to the patient. However, the majority of substances dispensed could be co-administered based on the Liverpool HEP iChart.