Hypersensitivity. Not to be co-administered w/ drugs highly dependent on CYP3A clearance eg, alfuzosin, astemizole, cisapride, colchicine (in patients w/ renal &/or hepatic impairment), dapoxetine, dronedarone, elbasvir/grazoprevir, ergot alkaloids, ivabradine, lomitapide, lovastatin, lurasidone, PO midazolam, naloxegol, pimozide, ranolazine, sildenafil (for PAH), simvastatin, terfenadine, triazolam. Not to be used w/ potent CYP3A inducers-containing products eg, rifampin or St. John's wort.