How do the antiarrhythmic drugs verapamil and diltiazem work?

Verapamil and diltiazem block channels mostly from the inside surface of the membrane by entering the channel preferentially when open [22,35,77]. In simple terms there is use-dependent block with benzothiazepines and phenylalkylamines but not with dihydropyridines [22].

How does verapamil work in the heart?

Verapamil is in a class of medications called calcium-channel blockers. It works by relaxing the blood vessels so the heart does not have to pump as hard. It also increases the supply of blood and oxygen to the heart and slows electrical activity in the heart to control the heart rate.

What is the mechanism of action for verapamil?

Mechanism of action: Verapamil inhibits the calcium ion (and possibly sodium ion) influx through slow channels into conductile and contractile myocardial cells and vascular smooth muscle cells.

What is the difference between verapamil and diltiazem?

Verapamil has a more profound effect on gut smooth muscle than the other calcium channel antagonists. It reduces gut motility and causes constipation. Like verapamil, diltiazem is an arteriolar dilator which reduces peripheral resistance and thus blood pressure, but it is less cardio depressant.

What is the antidote for calcium-channel blockers?

Traditionally, antidotes for CCB overdose have included calcium, glucagon, adrenergic drugs, and amrinone.

Are calcium-channel blockers bad for you?

Calcium-channel blockers are widely used as an effective treatment for hypertension and angina. Several studies have raised questions about their safety, suggesting that calcium-channel blockers can increase the rates of myocardial infarction (MI) and death, particularly in patients with heart disease.

Why is verapamil contraindicated in heart failure?

Due to potential negative inotropic and peripheral vasodilating effects, the use of CCBs may further depress cardiac output and blood pressure, which can be detrimental in these patients. The use of verapamil and diltiazem is specifically contraindicated under these circumstances.

Why verapamil is contraindicated in patient with heart failure?

The calcium channel blockers, verapamil and diltiazem, should generally be avoided in patients with CHF, as their negative inotropic effects may exacerbate the disease.

What foods to avoid while taking calcium channel blockers?

Avoid grapefruit products while taking certain calcium channel blockers. Grapefruit juice interacts with the drug and can affect heart rate and blood pressure. This can cause symptoms such as headaches and dizziness.

What is the antidote for calcium channel blockers?