1-Mechanism :

*blocking voltage-gated calcium channels in cardiac muscle and blood vessel----> decrease in cardiac contractility , and vasodilation.--->BP drops
*comparing to beta-blocker : maintain the control of sympathetic nervous system
*may be combine with beta-blocker
*dietary with magnesium supplements : increase the effects of ca channel blocker

2-classes:

*Dihydropyridine (amlodipine, benidipine, ): not used in angina
*Phenylalkylamin(verapamil..):reduce myocardial O2 demand
reverse coronary vasospasm
*Benzothiazepine(diltiazem): intermediate class between dihydropyridine and phenylalkylamin
*Non-selective: (fendiline, mibefradil....)

3-Common side effects:

*Tiredness
*Flushing
*Heartburn
*Swelling of the abdomen , ankles or feet

4- Contraindication :

*Bradydysrhythmias,
*SA node , or av node conduction disturbances
*hypotension
*Congestive heart disease
*Dilated myocardiopathy