Diltiazem is an oral and parenteral non-dihydropyridine calcium channel blocker. It is used in many clinical scenarios as an antihypertensive, anti-arrhythmic, and as an anti-anginal. FDA-approved indications include atrial arrhythmia, hypertension, paroxysmal supraventricular tachycardia, and chronic stable angina. Diltiazem also has numerous off-label indications. This activity will highlight the mechanism of action, adverse event profile, approved and off-label uses, dosing, pharmacodynamics, pharmacokinetics, monitoring, relevant interactions of diltiazem, pertinent for members of the interprofessional team using diltiazem for any of its intended indications.