There are five major classes of blood pressure-lowering drugs: angiotensin-converting enzyme inhibitors (ACEi), angiotensin receptor blockers (ARBs), beta-blockers, calcium channel blockers (CCB), and thiazide or thiazide-like diuretics. Broadly, these drugs have their effects by reducing blood volume and/or relaxing the smooth muscles that control the diameter of blood vessels.
A combination of an ACEi or ARB with a CCB or diuretic is the preferred initial therapy for most people with high blood pressure.[1] If blood pressure remains uncontrolled, a combination of an ACEi or ARB with a CCB and a diuretic is recommended.[1]