Hello,
thanks for the query

Metoprolol is a selective B1 receptor blocker. B1 is a receptor of the symathetic nervous system. The sympathetic nervous system acts through the chemical noradrenaline which increases heart rate, heart contraction and constriction of vessels (increase vasoconstriction increases peripheral resistance). The resultant effect is increase blood pressure as seen from the equation'
Blood pressure = Heart rate x stroke volume x peripheral resistance
Thus the effect of metoprolol is to partly block the effects of the sympathetic nervous system.

Lisinopril on the other hand is an angiostensin converting enzyme inhibitor. When cardiac out put is insufficient, the kidneys secret renin which becomes converted to angiotensin 1 in blood. Angiotensin 1 becomes converted to angiotensin 2 by the angiotensin converting enzyme which is found in the lungs. Angiotensin converting enzyme then converts angiotensin 1 to angiotensin 2 which is a powerful molecule which causes increase thirst, vasoconstriction and also causes secretion of aldosterone that will prevent sodium from being loss at the level of the kidneys. The resultant effect is water retention and vasocontrsiction thus increase blood pressure.

The above are two different pathophysiological mechanisms that play a role in hypertension thus the difference in both drugs is first of all the class to which they belong and then the mechanism of action of each.

Common side effects of metoprolol include dizziness, drowsiness, fatigue, trouble sleeping, depression,numbness of hands and feet and vision problems while those of lisinopril include cough, dizziness, drowsiness, headache, depressed mood, nausea, vomiting, and mild skin itching or rash.

However, the side effects are more common with increased doses.

Hope this answers your query. If you have further query, i will be glad to respond.
Best regards

---