Generic Calan is used for treating supraventricular tachycardia, a rhythm disturbance of the heart. It is also used for controlling heart rate response to other rhythm disturbances, specifically atrial fibrillation and atrial flutter.
Generic Zebeta is used for treatment of high blood pressure. It is a beta-blocker. It works by interfering with certain body chemicals, which cause the heart to beat with less force and pump out less blood.