macrolide antibiotics, cisapride, anti-arrhythmics, steroids, rifampicin, phenobarbital, phenytoin, secobarbital, carbamazepine, norethindrone, isoniazid. AZD9668 is metabolized by CYP3A4, 3A5, and 2B6. SAXA is metabolized by CYP3A4 and 3A5, potentially leading to drug-drug interactions with hypothetical adverse events in patients on the above agents. Also, AZD9668 causes weak inhibition of CYP2C9 and therefore patients on fluconazole, amiodarone, fenofibrate, fluvoxamine, phenylbutazone, probenecid, sertraline, will also be excluded to avoid the hypothetical adverse events due to this effect.