Toprol XL

Toprol-XL (or Metoprolol) - antiadrenergic drug, a selective beta1-adrenoblokator. It has hypotensive, antianginal and antiarrhythmic actions.

It reduces sinus node automatism, shortens cardiac rhythm, slows atrioventricular conduction and reduces myocardial contractility and excitability, cardiac output, myocardial oxygen demand. It suppresses stimulative catecholamine effect on heart during physical and psychoemotional activities, decreases plasma rennin activity. Metoprolol stabilizes cell membranes lowly and is not an agonist - has no intrinsic sympathomimetic activity.

Hypotensive effect is made conditional upon decrease of cardiac output and activity of rennin-angiotensin system, reduction of baroreceptor sensitivity and influence on the central nervous system. Antihypertensive effect is developed gradually and stabilized by the end of the 2-nd week after prescription of medicine. It does not cause orthostatic hypotension and has no effect on the electrolytic composition.

Antianginal effect is conditioned by reduction of myocardial oxygen demand and relocation of coronary blood flow. Antiarrhythmic action is conditioned by removal of arrhythmogenic sympathetic influence on cardiac conduction system, automatism inhibition, and excitement velocity.