Common names include:

• Hydrochlorothiazide (Hydrodiuril, Microzide)
• Indapamide (Lozol)
• Spironolactone (Aldactone)

Diuretics help the kidneys get rid of excess water and sodium. These medicines are sometimes referred to as “water pills.”

Possible side effects include:

• Dizziness
• Frequent urination

Common names include:

• Atenolol (Tenormin)
• Propranolol hydrochloride (Inderal)
• Metoprolol (Toprol)
• Nadolol (Corgard)
• Betaxolol (Kerlone)
• Acebutolol (Sectral)
• Pindolol (Visken)
• Bisoprolol (Zebeta)

Beta-blockers reduce demands on the heart by reducing the rate and force of contraction and help lower blood pressure.

Possible side effects include:

• Low blood pressure
• Slow heart rate
• Fatigue

Beta-blockers may not be the first-line treatment for hypertension.

Common names include:

• Benazepril hydrochloride (Lotensin)
• Captopril (Capoten)
• Enalapril (Vasotec)
• Quinapril (Accupril)
• Perindopril (Aceon)
• Ramipril (Altace)
• Trandolapril (Mavik)
• Fosinopril (Monopril)
• Moexipril (Univasc )
• Lisinopril (Zestril, Prinivil)

ACE inhibitors relax the blood vessels and lower blood pressure by blocking the production of a hormone that causes the blood vessels to constrict.

Possible side effects include:

• Headache
• Dizziness
• Cough

Common names include:

• Irbesartan (Avapro)
• Losartan potassium (Cozaar)
• Valsartan (Diovan)
• Candesartan (Atacand)
• Olmesartan (Benicar)
• Telmisartan (Micardis)
• Eprosartan (Teveten)

Angiotensin antagonists relax the blood vessels and lower blood pressure by shielding the blood vessels from a hormone that causes the blood vessels to constrict.

Possible side effects include:

Common names include:

• Verapamil hydrochloride (Calan SR)
• Diltiazem hydrochloride (Cardizem CD)
• Amlodipine (Norvasc)
• Sustained release nifedipine (Procardia XL, Adalat CC)
• Felodipine (Plendil)
• Nisoldipine (Sular)

Calcium channel blockers relax the blood vessels and lower blood pressure by blocking some activities of heart and blood vessel muscle cells.

Possible side effects include:

Common names include:

• Prazosin (Minipress)
• Terazosin (Hytrin)
• Doxazosin (Cardura)

Alpha-blockers lower blood pressure by decreasing nerve impulses to the blood vessels. This relaxes the blood vessels and helps lower blood pressure.

Possible side effects include:

• Dizziness
• Headache

Common names include:

• Labetalol (Normodyne, Trandate)
• Carvedilol (Coreg)

Alpha-beta blockers lower blood pressure by decreasing nerve impulses to the blood vessels. They also slow the heart rate and decrease the force of contraction. This decreases the workload of the heart and helps lower the blood pressure.

Possible side effects include:

• Dizziness
• Postural hypotension (blood pressure falls when standing up)

Common names include:

• Clonidine (Catapres)
• Methyldopa (Aldomet)

Nervous system drugs lower blood pressure by controlling nerve impulses and relaxing blood vessels. These drugs can be taken orally. Clonidine is available through a skin patch.

Possible side effects include:

• Dry mouth
• Drowsiness
• Dizziness
• Redness, itching, and skin irritation (with skin patch)

Hydralazine (Apresoline)

Vasodilators lower blood pressure by directly relaxing blood vessel walls.

Possible side effects include:

• Fluid retention
• Rapid heart rate