What is Tiazac?
Diltiazem (INN) () is a nondihydropyridines (non-DHP) calcium channel blocker used in the treatment of hypertension, angina pectoris, and some types of arrhythmia. It relaxes the smooth muscles in the walls of arteries, which opens (dilates) the arteries, allows blood to flow more easily, and lowers blood pressure. Additionally, it lowers blood pressure by acting on the heart itself to reduce the rate, strength, and conduction speed of each beat.
It is also used off-label as an effective preventive medication for migraine. It is a class 3 antianginal drug, and a class IV antiarrhythmic. It is a common adulterant of cocaine seized in the UK, and has been found to reduce cocaine cravings in rats, indicating it may prolong the "high" (see below).
Diltiazem is metabolized by and acts as an inhibitor of the CYP3A4 enzyme which can cause it to interact with a variety of other medications.