Alcohol, opioids (e.g., morphine, codeine, tramadol), other sedatives (sleeping pills, antihistamines like chlorpheniramine, antipsychotics), antidepressants, strong CYP3A4 inhibitors (ketoconazole, itraconazole, clarithromycin, erythromycin, ritonavir), grapefruit/grapefruit juice, valproate, diltiazem/verapamil