The flow of calcium in and out of cells is vital for the contraction of smooth muscle cells within blood vessel linings. Calcium flows in and out of cells through special protein channels. If these channels are partially inactivated, or blocked, then full contraction does not occur and blood vessels can dilate so blood pressure falls.
Calcium channel blockers (eg diltiazem, felodipine, isradipine, lacidipine, nicardipine, nifedipine) therefore work by:
- blocking the transport of calcium ions through cell membranes
- relaxing muscles in arterial walls and reducing arterial spasm
- dilating peripheral veins to encourage pooling of blood
- reducing the force of contraction of the heart.
On average, a calcium-channel blocker reduces systolic blood pressure (your upper reading) by 8.4 mmHg when used alone.
Treatment must not be stopped suddenly, but tailed off slowly to prevent rebound high blood pressure and angina.
If your blood pressure is raised, self-monitoring is key to maintaining good control.
Click here for advice on choosing a blood pressure monitor to use at home.
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