Alpha-blockers for treating high blood pressure
A group of medicines known as alpha-blockers may be prescribed for treating high blood pressure, but what are alpha-blockers and how do they work in lowering blood pressure?
If you have high blood pressure (hypertension), blood can struggle to flow normally because the muscular walls of your arteries have become hardened and stiff, making these vessels narrow and restricting the flow of blood. The more the blood pushes against the walls of the narrowed vessels as it tries to flow through, the higher your blood pressure will rise.
Alpha receptors are found within the muscle that lines the blood vessels. When these receptors are activated, they trigger the muscle to tighten up. As their name indicate, alpha-blockers can block the alpha receptors, so the muscle in the blood vessels remains relaxed and blood can flow more easily, thereby lowering your blood pressure.
Alpha-blockers – or alpha-adrenoceptor antagonists – are a group of medicines taken in tablet or capsule form that can help to lower blood pressure by blocking the alpha receptors. They are also used to treat men with an enlarged prostate who have trouble passing urine.
The four types of alpha-blockers available in the UK for lowering blood pressure are doxazosin, indoramin, prazosin, and terazosin.
When are alpha-blockers prescribed for treating high blood pressure?
Alpha-blockers are prescribed only after first trying other medicines, often as a third or fourth choice. There are several other types of medicines available for treating high blood pressure, including ACE inhibitors, calcium channel blockers, diuretics and beta-blockers.
Although alpha-blockers are as good as all of these other medicines at lowering blood pressure, they are not as useful as the others for protecting you if you have a heart attack or stroke or in cases of heart failure. The National Institute for Health and Care Excellence (NICE) has provided guidelines for the best treatment choices, and recommend alpha-blockers only if various combinations of the other medicines are ineffective, contraindicated or are not well tolerated.
If you are prescribed alpha-blockers, it is likely that you will be taking them in combination with some of these other medicines. In fact, up to three or four medicines may be necessary to successfully treat high blood pressure. Treatment will normally continue for the rest of your life.