mode of action

Last reviewed 01/2018

Diltiazem (benzthiazepine) impedes calcium transport across myocardial and vascular smooth muscle membranes.

The effects of this include:

  • prolongation of the slow component of action potential - effectively prolonging the refractory period
  • slowing conduction at the SA and AV node
  • less negative inotropy than verapamil
  • peripheral vasodilatation and a reduction in cardiac load

The combined effect of reducing cardiac load and of reducing myocardial contractility results in reduced myocardial oxygen requirements.