Diuretics are medicines that promote urination. Essentially, these drugs allow your kidneys to take more sodium into the urine. Note that the sodium takes with it water from the blood, hence the increased urination.
Basically, diuretics reduce the amount of fluid flowing through your blood vessels, significantly decreasing the blood pressure.
Beta-blockers are common hypertension medications. They help lower the blood pressure by blocking adrenaline, making the heart beat more slowly and with less force. Additionally, beta-blockers also promote blood flow by opening up the blood vessels.
ACE stands for angiotensin-converting enzymes. Basically, ACEs activate Angiotensin II, a chemical that narrows the blood vessels.
Now, taking ACE inhibitors means you inhibit or slow down the activity of ACEs. This means your body produces less of Angiotensin II, helping the blood vessels relax or open up and promoting blood flow.
Angiotensin II Receptor Blockers
Angiotensin II receptor blockers also lower blood pressure by relaxing the blood vessels. However, instead of inhibiting the enzyme, ARBs block the receptors that Angiotensin II needs to narrow the arteries and veins.