Verapamil

It is a diphenylalkylamine.

Action:
It causes a decrease in the AV conduction of the heart leading to decreased heart rate and demand for oxygen. It also causes a decrease in the firing time of the sinus node pacemaker.

It has more negative inotropic effect as compared to nifedipine but has weak vasodilation effect.

Verapamil may also produce local anesthetic action (due to less effective blockade of sodium channels).

Verapamil also cause inhibition of insulin release.

Pharmacokinetics:
The drug shows hepatic metabolism.

Administration:
Orally, Intravenously

Therapeutic uses:
It is used for supraventricular tachyarrhythmias.

Adverse effects:
Constipation

Contraindications:
It is contraindicated in:
1. Patients with already decreased cardiac function.
2. Patients with abnormalities of atrioventricular conduction.

Precautions:
It should be used with caution in patients with liver function abnormalities.
It should also be used with caution in patients taking digoxin as it may increase digoxin level.