 Calcium
channel blockers are effective in
treating hypertension because they reduce
peripheral resistance.
- Amlodipine and felodipine
have relatively little effects on reducing
myocardial contractility compared to verapamil or
diltiazem.
- Arteriolar vascular tone depends on free
intracellular Ca2+
concentration:
- Calcium channel blockers reduce
transmembrane movement of Ca2+
- reduce the amount reaching
intracellular sites and therefore
- reduce vascular smooth muscle
tone.
- All calcium channel blocks appear similarly
effective for management of mild to moderate
hypertension.
- For low-renin hypertensive patients
(elderly and African-American groups), Ca2+
channel blockers appear good choices for
monotherapy (single drug) control.
- Adverse
Effects
- SA nodal inhibition may lead to
bradycardia or SA nodal arrest.
This effect is more prominent if beta
adrenergic antagonists are concurrently
administered.
- GI reflux.
- Negative inotropic effects are
augmented if beta-adrenergic receptor
antagonists are concurrently
administered.
- Calcium channel blockers
should not be administered if the patient
has SA or AV nodal abnormalities or in
patients with significant congestive
heart failure.
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