Antihypertensive medications are available in many varieties. Some may be more appropriate than others for treating people with diabetes. Antihypertensive medications include:

• Vasodilators. Medications that expand or widen blood vessels, reducing blood pressure against the walls of the vessels. This allows blood to flow more freely and the heart to pump more efficiently. Vasodilators include:
  
  
• • ACE inhibitors (angiotensin-converting enzyme inhibitors). Block the production of an enzyme (angiotensin II) that causes blood vessels to tighten. Preventing this constriction allows more blood to flow into the heart and lowers blood pressure.
    
    
  • Angiotensin-II receptor blockers (ARBs). Produce the same effect as ACE inhibitors but by a different mechanism. Instead of preventing the production of angiotensin II, they inhibit the action of this substance by blocking it from entering angiotensin II receptors in the body. These drugs are also frequently prescribed for diabetes patients, especially those who have or are at risk for kidney disease (diabetic nephropathy). Some research indicates that ACE inhibitors and ARBs may reduce the risk of developing type 2 diabetes.
    
    
  • Calcium channel blockers (CCBs). Reduce the workload of the heart by blocking calcium ions from signaling the blood vessels to constrict or tighten. They are commonly prescribed for those with diabetes and are particularly effective when used in combination with ACE inhibitors or angiotensin II receptor blockers. They may be prescribed for conditions including angina, coronary artery disease, coronary spasms, arrhythmias and a type of stroke called subarachnoid hemorrhage.  A recently approved drug combines a CCB with a cholesterol drug to treat two common risk factors for heart disease and diabetes.
    
    
  • Central adrenergic inhibitors. Act directly on the brain to prevent it from signaling the central nervous system to increase heart rate or narrow blood vessels.
    
    
  • Renin inhibitors. Help blood vessels relax and widen by reducing the effect of renin, an enzyme made in the kidneys. The U.S. Food and Drug Administration approved the first renin inhibitor in 2007.
    
    
• Alpha blockers. Medications that reduce the workload of the heart by blocking certain chemicals from binding with alpha receptors in the heart, which relaxes the smooth muscle in the walls of blood vessels. Alpha blockers are often prescribed to treat prostate enlargement (benign prostatic hyperplasia).
  
  
• Beta blockers. Reduce the workload of the heart by blocking some effects of the sympathetic nervous system, which may release certain chemicals that bind with beta receptors in the heart. Binding could trigger a rapid heartbeat. Beta blockers may be the first-line treatment for people with diabetes and heart conditions, such as heart failure, angina, heart attack, arrhythmia or palpitations. They can also treat glaucoma. However, they are often not chosen as first-line treatment for people with diabetes alone, as they can mask symptoms of hypoglycemia in some patients. In addition, several studies have shown that beta blockers can cause hyperglycemia and may even be a risk factor for secondary diabetes.

Beta blockers may be prescribed as thyroid medications to treat Graves’ disease and other forms of hyperthyroidism. Beta blockers and other antihypertensives may be prescribed as headache medications to prevent migraines or cluster headaches.

• Diuretics. Promote the formation of urine in the kidneys, causing the body to flush out fluids and minerals including sodium. The reduction in fluid volume and sodium levels causes blood vessels to widen, increasing blood flow and reducing the pressure of blood against the vessels. Of the four types of diuretics (sometimes called water pills), the three used in the treatment of hypertension are loop, potassium-sparing and thiazide. However, as with beta blockers, some research has indicated that diuretics can raise glucose (blood sugar) and possibly lead to secondary diabetes. Diuretics can also be prescribed for conditions including heart failure, glaucoma and the nephrogenic form of diabetes insipidus.

Some antihypertensive drugs have shown other benefits for diabetic individuals. High blood pressure increases the odds of developing kidney disease in people with diabetes. ACE inhibitors and angiotensin II receptor blockers have been shown to protect the kidneys of those with diabetes and can either slow or prevent kidney damage. These drugs are sometimes prescribed to protect the kidneys in diabetic patients who do not have high blood pressure. The U.S. government’s ALLHAT project (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) found diuretics especially effective for black Americans, including reducing the risk of stroke.

Physicians choose which antihypertensive to prescribe based on each patient’s medical history and symptoms and conditions. Considerations include kidney function, cardiovascular health, eye health, glucose control and tendency to have hypoglycemia unawareness.

If the use of a single antihypertensive does not lower blood pressure sufficiently, then physicians may prescribe two or more types of antihypertensives to work in combination. Combination therapies are usually not first-line treatments but offer a valuable alternative when traditional therapies are not effective. They allow for lower, better-tolerated doses of each antihypertensive.

Some combinations are available in single fixed-dose pills so that although patients are taking more than one medication, they are taking only one pill. The most common combination therapies include:

• ACE inhibitors and thiazide diuretics
• Angiotensin II receptor blockers, thiazide diuretics and potassium-sparing diuretics
• Beta blockers and thiazide diuretics
• Thiazide diuretics and potassium-sparing diuretics
• Calcium channel blockers and ACE inhibitors
• Renin inhibitors and diuretics

Whether or not medication is required to control hypertension, patients will be advised to make lifestyle modifications (healthy diet, weight loss, exercise, quitting smoking) to help control their condition.