What is an Alpha Blocker?

Mary McMahon
Mary McMahon

An alpha blocker is a medication designed to block the function of receptors in the body involved in muscle contractions, vasodilation, and the release of certain hormones. These receptors, known as alpha-adrenergic receptors, are found throughout the body. Doctors can prescribe alpha blockers to treat conditions like high blood pressure, scleroderma, prostate enlargement, and Raynaud's disease. These medications are available by prescription only for safety and come in fast-acting and extended release formats.

A physician may prescribe an alpha blocker to lower high blood pressure.
A physician may prescribe an alpha blocker to lower high blood pressure.

Alpha blocker medications work by locking onto alpha-adrenergic receptors, preventing them from reacting to chemical compounds like adrenaline released by the body. In one example, alpha receptors line the blood vessels and signal muscle contractions when chemicals are released, causing the blood vessels to narrow. When people take an alpha blocker, the signals to contract don't reach as many receptors and the vessels stay relaxed and dilated, keeping blood pressure low. That relaxing effect can also help with issues like difficulty urinating or poor circulation caused by narrowing blood vessels.

Alpha blockers effect blood pressure by preventing signals to contract from reaching the blood vessels, making blood flow easier.
Alpha blockers effect blood pressure by preventing signals to contract from reaching the blood vessels, making blood flow easier.

These medications have what is known as a first dose effect as the body adjusts to the medication. When an alpha blocker is taken for the first time, blood pressure drops and the patient may feel dizzy and disoriented. Over time, the patient gets used to the medication and these symptoms should not occur. Other potential alpha blocker side effects include weight gain, headache, pounding heart, and nausea.

Headaches are one possible side effect of using alpha blockers.
Headaches are one possible side effect of using alpha blockers.

If a doctor recommends an alpha blocker, it is usually after other measures to control a medical issue have failed and medication seems like the best option. Medications are available in varying formats and dosages, and it is important to ask for clear instructions on using the medication safely and reliably. Even patients who have taken such medications before should get directions, as a change of medication may result in different use directions. The medications should be kept in a safe place, as they can be potentially dangerous for some people due to the first dose effect.

Cold or numbness in the toes may be a symptom of Raynaud's disease, which can be treated with alpha blockers.
Cold or numbness in the toes may be a symptom of Raynaud's disease, which can be treated with alpha blockers.

Drug interactions while on alpha blocker drugs are possible. Patients should make sure all their prescriptions are listed in their charts and pharmacy records to allow medical professionals to check for any potential bad interactions before writing or releasing a prescription. Patients using over-the-counter medications should ask about the potential for drug interactions. A pharmacist or doctor can provide more information and discuss alternatives if a particular over-the-counter medication is not safe for the patient to use.

Alpha blockers are typically available by prescription only.
Alpha blockers are typically available by prescription only.
Alpha blockers may be prescribed to treat scleroderma, a condition characterized by the hardening of the skin.
Alpha blockers may be prescribed to treat scleroderma, a condition characterized by the hardening of the skin.
Alpha blockers may help treat prostate enlargement.
Alpha blockers may help treat prostate enlargement.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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