• Thiazide diuretics. Diuretics, sometimes called water pills, are medications that act on your kidneys to help your body eliminate sodium and water, reducing blood volume. Thiazide diuretics are often the first — but not the only — choice in high blood pressure medications. If you're not taking a diuretic and your blood pressure remains high, talk to your doctor about adding one or replacing a drug you currently take with a diuretic.
• Beta blockers. These medications reduce the workload on your heart and open your blood vessels, causing your heart to beat slower and with less force. When prescribed alone, beta blockers don't work as well in blacks or in older adults — but they're effective when combined with a thiazide diuretic.
• Angiotensin-converting enzyme (ACE) inhibitors. These medications help relax blood vessels by blocking the formation of a natural chemical that narrows blood vessels.
• Angiotensin II receptor blockers (ARBs). These medications help relax blood vessels by blocking the action — not the formation — of a natural chemical that narrows blood vessels.
• Calcium channel blockers. These medications help relax the muscles of your blood vessels. Some slow your heart rate. Calcium channel blockers may work better for blacks and older adults than do ACE inhibitors or beta blockers alone. A word of caution for grapefruit lovers, though. Grapefruit juice interacts with some calcium channel blockers, increasing blood levels of the medication and putting you at higher risk of side effects. Talk to your doctor or pharmacist if you're concerned about interactions.
• Renin inhibitors. Aliskiren (Tekturna) slows down the production of renin, an enzyme produced by your kidneys that starts a chain of chemical steps that increases blood pressure. Tekturna works by reducing the ability of renin to begin this process. Due to a risk of serious complications, including stroke, you shouldn't take aliskiren with ACE inhibitors or ARBs.

If you're having trouble reaching your blood pressure goal with combinations of the above medications, your doctor may prescribe:

• Alpha blockers. These medications reduce nerve impulses to blood vessels, reducing the effects of natural chemicals that narrow blood vessels.
• Alpha-beta blockers. In addition to reducing nerve impulses to blood vessels, alpha-beta blockers slow the heartbeat to reduce the amount of blood that must be pumped through the vessels.
• Central-acting agents. These medications prevent your brain from signaling your nervous system to increase your heart rate and narrow your blood vessels.
• Vasodilators. These medications work directly on the muscles in the walls of your arteries, preventing the muscles from tightening and your arteries from narrowing.

Once your blood pressure is under control, your doctor may have you take a daily aspirin to reduce your risk of cardiovascular disorders.

To reduce the number of daily medication doses you need, your doctor may prescribe a combination of low-dose medications rather than larger doses of one single drug. In fact, two or more blood pressure drugs often work better than one. Sometimes finding the most effective medication — or combination of drugs — is a matter of trial and error.

Lifestyle changes to treat high blood pressure
No matter what medications your doctor prescribes to treat your high blood pressure, you'll need to make lifestyle changes to lower your blood pressure. These changes usually include eating a healthier diet with less salt (the Dietary Approaches to Stop Hypertension, or DASH, diet), exercising more, quitting smoking and losing weight.

Resistant hypertension: When your blood pressure is difficult to control
If your blood pressure remains stubbornly high despite taking at least three different types of high blood pressure drugs, one of which should be a diuretic, you may have resistant hypertension. Resistant hypertension is blood pressure that's resistant to treatment. People who have controlled high blood pressure but are taking four different types of medications at the same time to achieve that control also are considered to have resistant hypertension.

Having resistant hypertension doesn't mean your blood pressure will never get lower. In fact, if you and your doctor can identify what's behind your persistently high blood pressure, there's a good chance you can meet your goal with the help of treatment that's more effective.

Your doctor or hypertension specialist can evaluate whether the medications and doses you're taking for your high blood pressure are appropriate. You may have to fine-tune your medications to come up with the most effective combination and doses.

In addition, you and your doctor can review medications you're taking for other conditions. Some medications, foods or supplements can worsen high blood pressure or prevent your high blood pressure medications from working effectively. Be open and honest with your doctor about all the medications or supplements you take.

If you don't take your high blood pressure medications exactly as directed, your blood pressure can pay the price. If you skip doses because you can't afford the medication, because you have side effects or because you simply forget to take your medications, talk to your doctor about solutions. Don't change your treatment without your doctor's guidance.

What Are the Side Effects of High Blood Pressure Drugs?
As is true with any medication, high blood pressure drugs have side effects. Among the most common are the following:
Diuretics: headache, weakness, low potassium blood levels

ACE inhibitors: dry and persistent cough, headache, diarrhea, high potassium blood levels

Angiotensin receptor blockers: fatigue, dizziness or fainting, diarrhea, high potassium blood levels

Calcium channel blockers: dizziness, heart rhythm problems, ankle swelling

Beta-blockers: dizziness or lightheadedness, decreased sexual ability, drowsiness, low heart rate

Alpha-blockers: dizziness, headache, pounding heartbeat, nausea, weakness, weight gain

When should you call your doctor if you have high blood pressure?

If you are diagnosed with high blood pressure, it's important to see your doctor on a regular basis. He or she can answer your questions during these visits.

However, there may be other times when you may need to speak to your doctor. For instance:

If you aren't responding to the prescribed treatment and your blood pressure is still high

If you are having any side effects from the blood pressure medication; if this happens, your doctor may wish to adjust the dosage of the medication or put you on another medication.

Are There any Drugs that Cause High Blood Pressure?

Some drugs that you take for another condition may increase blood pressure. These include amphetamines, methylphenidate (Concerta, Metadate, Methylin, Ritalin), corticosteroids, hormones (including birth control pills), certain migraine medications, cyclosporine, and erythropoietin.

Also, many over-the-counter medications that contain pseudoephedrine and ephedrine (for example, allergy and cold medicines and appetite suppressants) can increase blood pressure.

Don't stop taking any prescribed medication, including high blood pressure drugs, without talking to your doctor.