Alpha blockers: Uses, common brands, and safety info

Alpha blockers (α-blockers) are a class of medications that block alpha receptors in the body. They are widely available as both generic and brand-name medications. They treat benign prostatic hyperplasia (BPH) by relaxing the smooth muscles in the bladder. They also treat high blood pressure by relaxing blood vessels to ensure smooth blood flow to and from the heart. Some common side effects include a sudden drop in blood pressure after standing or sitting up, dizziness, and fatigue. Use the table below to find examples of common alpha blocker medications.

What are alpha blockers?

Alpha blockers are a class of adrenergic blockers that work by antagonizing alpha adrenoceptors in the body. Examples include Cardura, Cardura XL (doxazosin), Minipress (prazosin), terazosin, Flomax (tamsulosin), Uroxatral (alfuzosin ER) , Rapaflo (silodosin), and Dibenzyline (phenoxybenzamine). 

Alpha blockers are the first choice for patients who have benign prostatic hyperplasia (BPH). They are also utilized in hypertension cases that are resistant or difficult to treat.

How do alpha blockers work?

Alpha blockers target the autonomic nervous system to relax the smooth muscles in various areas of the body, which results in lower blood pressure or improved urine flow. In the cardiovascular system, they dilate or widen the blood vessels to decrease blood pressure. In the urinary tract, they widen the bladder neck to improve urine flow and reduce any obstruction that may be caused by either an enlarged prostate or a kidney stone. Alpha blockers work right away, but four to six weeks of treatment may be required to see their optimal effects.

What are alpha blockers used for?

• Hypertension, or high blood pressure.

• Benign prostatic hyperplasiaprostate, or benign prostatic hypertrophy, which is a condition that affects older men where their prostate gland abnormally grows and pinches the urethra. This enlargement can cause uncomfortable lower urinary tract symptoms, including difficulty urinating, frequent urination, urinary retention, and loss of bladder control. This growth is not cancerous in nature and should not be confused with prostate cancer.

• Nightmares associated with post-traumatic stress disorder (PTSD).

• Pheochromocytoma, which is a tumor in the adrenal glands that secretes hormones causing hypertension and excessive sweating.

• Nephrolithiasis, or or kidney stones in women (off-label use). 

Types of alpha blockers

Non-selective alpha-1 receptor blockers

These agents block all alpha-1 receptors with no selectivity. There are three types of alpha receptors: 1A, 1B, and 1D. This subclass is used in hypertension and BPH. These agents have more side effects since they can bind receptors in multiple areas of the body. These are often given at bedtime to help minimize these side effects. Examples of nonselective alpha-1 receptor blockers include:

• Terazosin

• Cardura

• Cardura XL

• Minipress

Selective alpha-1A receptor blockers

The agents in this class selectively block alpha-1A receptors. The prostate primarily has alpha-1A receptors. Agents in this subclass are used to improve urine flow in BPH patients. They are also commonly used to relax the ureters to help pass kidney stones. Examples of selective alpha-1A receptor blockers include:

• Flomax

• Uroxatral

• Rapaflo

RELATED: Flomax dosage, forms, and strengths

Nonselective alpha receptor blockers

These agents antagonize all alpha adrenergic receptors. They are used in the treatment of pheochromocytoma to control episodes of hypertension and sweating. Examples of nonselective alpha receptor blockers include:

• Dibenzyline (phenoxybenzamine hydrochloride)

Who can take alpha blockers?

Men

Alpha blockers are mostly used in the male population as they are the only ones affected by BPH.

Women

Alpha blockers can be used off-label in women to aid the release of kidney stones. They can also relax the smooth muscles in the bladder for those who have difficulty passing urine. 

Pregnancy or breastfeeding

Most medications in the alpha blockers class should be used with caution during pregnancy, as there is inadequate human data available to fully assess risk. The only exception in this class is phenoxybenzamine where the benefits outweigh the risks. Some alpha blockers, like alfuzosin and silodosin, are only FDA approved for use in males.

Alternatives should be considered while breastfeeding because there is a lack of data on the risk of infant harm or effects on milk production.

Children

Alpha blockers can be used in pediatric patients for various conditions. Prazosin is used in managing PTSD-associated nightmares and as an adjunct in pheochromocytoma treatment. Dibenzyline is also an adjunct in pheochromocytoma. Tamsulosin can be used to aid in passing kidney stones.

Currently, there are no special liquid formulations commercially available for kids. 

Seniors

Alpha blockers can be used in the geriatric population. However, this group has multiple risk factors that make orthostatic hypotension, a common adverse effect of this medication class, a concern. They may also experience urinary incontinence and have to get up multiple times at night to urinate. Caution should be used when starting older adults on alpha blockers as all the aforementioned risk factors can further increase their risk of falls, fractures, and head injuries. Their cardiology and urology health care teams should work together with their pharmacy team to ensure they can safely take alpha blockers.

Older adults are more likely to be prescribed blood pressure medications like diuretics, calcium channel blockers, angiotensin receptor blockers, and beta blockers, or PDE-5 inhibitors for erectile dysfunction.

Are alpha blockers safe?

Alpha blockers are generally safe. None of the medications in this class have black box warnings, there have been no recent recalls on alpha blockers, and they are not controlled substances. However, there are some restrictions to these drugs:

Do not use alpha blockers:

• If hypersensitive to the drug or class

• With strong CYP 3A4 inhibitors

• In hepatic impairment (silodosin or alfuzosin)

Use alpha blockers with caution:

• In cataract surgery as there is a risk for intra-operative floppy iris syndrome

• In hypotension 

Also, avoid the use of alpha blockers with other drugs that lower blood pressure or PDE-5 inhibitors due to additive hypotensive effects. Patients should be stable on an alpha blocker before the PDE-5 inhibitor is initiated at the lowest dose, and vice versa. 

Common alpha blockers side effects

Side effects vary by medication, but these are some common side effects across popular alpha blockers:

• Orthostatic hypotension, or orthostasis, which is a sudden drop in blood pressure that happens soon after standing or sitting up. The risk of this occurring is higher with the first dose of this medication, any recent dose increase, or when used in combination with other antihypertensive agents or PDE-5 inhibitors.

• Dizziness or drowsiness

• Fatigue

• Headache

• Fluid retention

• Abnormal ejaculation

• Priapism, or a prolonged and painful erection lasting four or more hours

• Angina, or chest pain

• Intra-operative floppy iris syndrome (IFIS), which is poor pupil dilation during cataract surgery in patients taking alpha blockers. IFIS has the potential to derail cataract surgery, especially if it is unexpected.

Speak with your healthcare provider or pharmacist if you experience any of these effects and they persist or worsen. Many patients using this medication do not have any serious adverse effects.

How much do alpha blockers cost?

Alpha blockers are available as both generic and brand medications. They may have varying costs based on the type of health insurance coverage that you have. Contact your insurance provider directly to find out how much tamsulosin HCl costs with your plan.

The approximate cash price of alpha blockers, without insurance, ranges from $25 to more than $200. SingleCare coupons can be used instead of insurance and are available online for most prescription drugs. Pay as low as $7 when you use your SingleCare discount card at neighborhood pharmacies.