ACE inhibitors and Beta-blockers are medications used to control high blood pressure, and they differ in their mode of action. ACE actually stands for Angiotensin-converting enzymes. This is a product released from the kidney as adrenal glands when the body detects that there is no efficient circulation of blood to carry nutrients through the body. This leads to the existence of Aldosterone, which constricts the blood vessels and thus allows the mass flow of blood. Hence, the ACE inhibitors fight the action of the aldosterone by dilating the blood vessels, and also increasing the amount of urination, and thereby reducing blood pressure.
On the other hand, Beta-blockers are a medication that works on the adrenaline, together with other hormones that can lead to stress. Adrenaline is a hormone that increases one's blood pressure by increasing your compression and cardiac arrest, heightening your senses, and constricting your blood vessels. However, the intake of beta-blockers reduces the effects of the adrenaline in the body.