Diltiazem

Provider Level

RN/Paramedic

Class

Calcium channel blocker (non-dihydropyridine), Class IV antiarrhythmic

Mechanism of Action

Inhibits extracellular calcium ion influx across membranes of myocardial cells and vascular smooth muscle cells. Slows SA and AV node conduction and prolongs AV node refractory period, leading to a decreased ventricular rate.

Indications

Rapid ventricular rates associated with atrial fibrillation and atrial flutter. Paroxysmal supraventricular tachycardia (PSVT) refractory to adenosine.

Contraindications

Hypersensitivity, sick sinus syndrome, second or third-degree AV block (unless functioning pacemaker is present), severe hypotension or cardiogenic shock, wide-complex tachycardia, poison or drug-induced tachycardia, Wolff-Parkinson-White (WPW) syndrome.

Routes

IV, IO

Onset / Duration

Onset: 2 to 5 minutes. Peak effect: 2 to 7 minutes. Duration: 1 to 3 hours.

Adverse Effects

Hypotension, bradycardia, AV block, asystole, nausea, vomiting, dizziness, headache, flushing, chest pain.

Precautions & Interactions

Use caution in patients with impaired renal or hepatic function, heart failure, or those currently taking oral beta-blockers due to synergistic effects on myocardial contractility and AV conduction.

Special Considerations

Continuous ECG and frequent blood pressure monitoring are required during administration. Calcium chloride or calcium gluconate may be required to treat severe hypotension or block toxicity. Not intended for use in wide-complex tachycardias of uncertain origin.