Alpha-Blockers

What are alpha-blockers?

Alpha-blockers are medications that treat high blood pressure. They attach to alpha-receptors on cells to keep them from performing an action.

Common examples of alpha-blockers for high blood pressure include doxazosin, prazosin and terazosin.

Healthcare providers commonly prescribe alpha-blockers for several conditions, like an enlarged prostate. Other names for alpha-blockers are:

• Alpha adrenergic blockers or antagonists
• Alpha-antagonists
• Alpha-adrenoceptor blockers

Types of alpha-receptors

There are two types of alpha receptors:

• Alpha-1 receptors are in blood vessels, especially in your skin, kidneys, digestive organs and brain. They’re also in your prostate, ureters and eye muscles. They make blood vessels tighten, increasing blood pressure.
• Alpha-2 receptors are mostly in your brain and nerve endings that communicate with other nerves or blood vessels. They’re also in your pancreas, fat cells and blood vessels. They slow your nervous system to keep everything calm.

Types of alpha-blockers

There are two types of alpha-blockers — selective and non-selective. Both can affect your blood pressure.

Selective alpha blockers target specific alpha-1 receptors to decrease your blood pressure or relax muscles. Examples include:

• Alfuzosin
• Doxazosin
• Prazosin
• Silodosin
• Tamsulosin
• Terazosin

Non-selective blockers target both alpha-1 and alpha-2 receptors. They work more broadly but have more side effects. Because they also block alpha-2 receptors, they increase the amount of norepinephrine — a stress hormone — in your system. This increases your blood pressure and heart rate and can make you feel jittery. Examples include phenoxybenzamine and phentolamine.

Other medical conditions an alpha-blocker can treat

Besides high blood pressure, alpha-blockers can help with:

• Benign prostatic hyperplasia (BPH), an enlarged prostate that makes it hard to pee
• Tumors that can create extra adrenaline and norepinephrine
• Skin at risk from norepinephrine leaking out of your blood vessels and into nearby tissue
• Reversal of the effects of some local anesthetics
• Post-traumatic stress disorder (PTSD)
• Raynaud’s phenomenon
• Prostatitis (inflammation)
• Chronic pelvic pain syndrome
• Kidney stones stuck in your ureters (tubes between your kidneys and bladder)
• Symptoms from ureteral stents

How long will I need alpha-blockers?

For conditions like high blood pressure or benign prostate hyperplasia, it’s common to take an alpha-blocker long-term. For other conditions, you might only need to take them short-term. Your healthcare provider will explain options to you and help you decide what works best for you. They can tell you how long you’ll need to follow that course of treatment.

Depending on the medication and the condition you have, you can take some alpha-blockers long-term. Others are meant for short-term use.

You should never stop taking an alpha-blocker without talking to your healthcare provider. That’s because suddenly stopping them can cause serious complications. Some of these can be severe or even life-threatening.

Depending on why you take an alpha-blocker, your provider may tell you to stop taking them if:

• You lower your blood pressure through physical activity and nutritious foods so that you no longer need medicine to manage it
• You have a medical procedure (like prostate removal) that removes your need for an alpha-blocker
• You switch to another medicine that isn’t an alpha-blocker but still has the same effect

What are the potential benefits and risks of this treatment?

Alpha-blockers can offer a treatment option that avoids surgery for certain conditions. But like other medicines, alpha-blockers have side effects.

Selective alpha-1-blocking medications often cause these side effects:

• Low blood pressure (hypotension)
• First-dose effect (a much stronger effect on blood pressure at first than later doses)
• Dizziness
• Priapism, an erection that lasts four or more hours

Non-selective alpha-blockers may cause these side effects:

• Weakness
• Fast heartbeat
• Muscle tremors

Some alpha-blocker medications may interact with alcohol, citrus juices or other foods. Alpha-blockers can also interact with many other medicines. Effects can vary from person to person. Your healthcare provider is the best source of information on how alpha-blockers are most likely to affect you.

Who should not take alpha-blockers?

There are several health concerns (contraindications) that can prevent you from taking alpha-blockers. These include:

• Cataract surgery: Because alpha-blockers affect the pupils in your eyes, they can cause complications during cataract surgery. Intraoperative floppy iris syndrome is a common example of this.
• Breastfeeding: When breastfeeding, avoid taking non-selective alpha-blockers.
• History of orthostatic hypotension: Taking alpha-blockers can make this condition worse.
• Erectile dysfunction medications: In some cases, certain erectile dysfunction medicines can interact with alpha-blockers.
• Kidney disease, circulatory diseases or respiratory infections: Non-selective alpha-blockers may not be an option if you have one or more of these conditions.

How long will it take for me to feel better?

Selective alpha-1 blockers can relieve symptoms in a few days.

Is there anything I can do to make this treatment easier on me?

Yes. Take your first dose of a selective alpha-1-blocker right before you go to bed. The effect of the first dose can be strong and can cause orthostatic hypotension. This means your blood pressure drops quickly when you stand up.

When should I call my healthcare provider?

In general, you should contact your provider if you have any sudden changes in your symptoms, especially when they keep you from your regular activities.

You should seek medical care right away if you have any of these:

• Fainting or passing out
• Chest pain (angina)
• Shortness of breath
• Fast or irregular heartbeat
• Heart palpitations
• Priapism (a painful, four-hour erection)
• Symptoms of a severe allergic reaction (anaphylaxis) like hives, rash, itching, swelling and difficulty swallowing