There are many over-the-counter drugs available for controlling high or low blood pressure, but its best to consult a physician before taking any medication to avoid complications.

Angiotensin II is a hormone that causes blood vessels to constrict. Drugs such as angiotensin can block this hormone and cause blood vessels to relax.

Nerve impulses might also cause the flow of blood to slow and blood pressure to increase. These impulses can be slowed with alpha-blockers, alpha-beta-blockers, and beta-blockers. Beta-blockers also reduce the heartbeat and blood flow to control blood pressure. The nervous system inhibitors, Vasodilators are used when blood vessels are to be opened directly.

If calcium enters invades heart muscles or blood vessels, arteries constrict, calling for the use of calcium channel blockers or the drug Minoxidil.

Another reason for increased blood pressure is excess water and minerals such as sodium in the kidney. Diuretics or diuretic preparations like indapamide can control these.

Peripheral artery walls can be relaxed using hydralazine.

And some drugs such as methyldopa and moxonidine can be helpful in stimulating the alpha-receptors in the brain to relax blood vessels.

High blood pressure has a variety of causes and should be properly diagnosed and prescribed for by a physician. It is important to remember that high or low blood pressure is an indicator that the heart is working too hard, or that the heart is not experiencing enough resistance. The imbalance should be restored with a combination of proper diet, aerobic exercise, and, if necessary, blood pressure medications.