18. The use of concomitant medications, including prescription, over the counter medications, herbal medications, inducers or inhibitors of CYP enzymes, glucuronidation or drug transporters (including P-glycoprotein and OATP1B1) within 14 days or 5 half-lives (whichever is longer) prior to the first dose of study medication is excluded, unless approved by the Sponsor's Medical Monitor. Occasional use of paracetamol, or its equivalent, is permitted.