Calcium Channel Blockers - Med Spotlight

I am starting a series called “Med Spotlight.” I thought this would give providers a good place to go for reference on different medications. In these blogs I’ll point out some mechanism of action information, as well as logistics of how to give the medication. I’ve received some questions on cardizem from different clinicians lately, so we will focus mostly on that medication in this blog. First, let's take a look at all the different types of calcium channel blockers that are used. Calcium channel blockers are broken down into several sections, all having different actions on cardiac conduction, inotropic force, and vascular tone.

Calcium channel blockers generally block the L-type calcium channels. For our purposes today, these L-types are found in cardiac muscle, nodal tissue (SA and AV), as well as the arteries. When these channels are blocked, less calcium can influx, resulting in a depression of those cells main function. In the cardiac muscle, less inotropic squeeze. In the nodal tissue, a slow firing rate/slower heart rate (negative chronotropic). In the arterial smooth tissue, a wider diameter (lower peripheral vascular resistance).