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- What is high blood pressure (hypertension)?
- Which lifestyle modifications are beneficial in treating high blood pressure?
- Coffee and caffeinated beverages
- Other dietary considerations
- Exercise and stress reduction
- How is high blood pressure treated?
- Starting treatment for high blood pressure
- Treatment with combinations of drugs for high blood pressure
- Emergency treatment for high blood pressure
- Treatment during pregnancy
- Which medications are used to treat high blood pressure?
- Beta blockers
- Calcium channel blockers (CCBs)
- Alpha blockers
- Renin inhibitors
- Aldosterone blockers
- Combining agents
- What about the patient's compliance with medication regimens?
- Is alternative medicine used to treat high blood pressure?
- What are the complications of high blood pressure?
- Can high blood pressure be prevented?
- What's new in high blood pressure?
Quick GuideHigh Blood Pressure Symptoms, Causes, Treatments
Alpha blockers lower blood pressure by blocking alpha-receptors in the smooth muscle of peripheral arteries throughout the tissues of the body. The alpha-receptors are part of the sympathetic nervous system, as are the beta-receptors. The alpha-receptors, however, serve to constrict the peripheral arteries and the alpha-blockers cause the peripheral arteries to widen (dilate) and lower the blood pressure.
Evidence suggests using alpha blockers alone as a first-line drug choice for hypertension may actually increase the risk of heart-related problems, such as heart attacks or strokes. Alpha blockers should not be used as the initial drug for the treatment of high blood pressure. Examples of alpha blockers include terazosin (Hytrin), prazosin (Minipress), and doxazosin (Cardura).
Alpha blockers are particularly useful in patients with enlargement of the prostate gland because these drugs reduce the problems associated with urinating. The alpha-receptors, however, serve to constrict the peripheral arteries and the alpha blockers cause the peripheral arteries to widen (dilate) and lower the blood pressure. Tamsulosin (Flomax) or alfuzosin (Uroxatral) are alpha blockers that work well in combination with other antihypertensive medications.
Clonidine (Catapres) is an antihypertensive drug that works centrally. That is, it works in a control center for the sympathetic nervous system in the brain. The drug is referred to as a central alpha agonist because it stimulates alpha-receptors in the brain. The result of this central stimulation is to decrease the sympathetic nervous system outflow and to decrease the stiffness (resistance) of the peripheral arteries. Clonidine lowers the blood pressure by relaxing (dilating or widening) the peripheral arteries throughout the body. This drug is useful as a second- or third-tier choice for lowering blood pressure when other antihypertensive medications have failed. It also may be useful on an as-needed basis to control or smooth out fluctuations in the blood pressure. This drug tends to cause dryness of the mouth and fatigue so some patients do not tolerate it. Clonidine comes in an oral form or as a sustained release skin patch.