What Are The Side Effects Of Alpha-Blockers?

Blood pressure is a medical statistic used to see how hard a person’s heart needs to work to pump blood through their body.

High blood pressure is a common problem that is identified in the modern-day. The condition is also called hypertension1. It refers to an increase in the amount of pressure applied to arteries and blood vessels.

Alpha-blockers are the most common drug used to help men and women with high blood pressure.

Even though most often used for hypertension, alpha-blockers are sometimes prescribed for other conditions too. These drugs work effectively but do come with some significant alpha blocker side-effects that patients should know.

We take a look at what alpha-blockers are in this post. We also consider the conditions that alpha-blockers are used to treat. Furthermore, we look at the various side-effects that patients may experience when they take an alpha-blocker.

What Are Alpha-Blockers?

Alpha-blockers are mostly known as drugs used to treat hypertension. This is generally not considered first-line therapy. These drugs contain chemicals that work against a hormone in the body.

The hormone is known as norepinephrine. This hormone is known to cause the walls of small veins and arteries to narrow. The effect is caused by a tightening of the muscles in the walls of the arteries. These are different than beta-blockers and calcium channel blockers.

When smooth muscle tissue in these arteries tightens, blood pressure may increase. The heart needs to pump harder to get blood through the body. This causes strain on the walls of blood vessels. Long-term hypertension that is not treated can cause serious problems.

Norepinephrine’s action on the muscles located in artery walls is blocked when an alpha-blocker is taken2. This ensures the muscles not to tighten. The drug ensures blood vessels can remain dilated. It also ensures the muscles in arteries remain relaxed.

These actions help to provide an improvement in blood circulation. The effects are also beneficial for reducing blood pressure levels.

There are a few other names that may also be given for alpha-blockers. Sometimes, doctors may refer to these drugs as:

  • Adrenergic blocking agents

  • Alpha-blocking agents

  • Alpha-adrenergic antagonists

  • Alpha-adrenergic blocking agents

Regardless of the name used, these are all terms that refer to the same group of drugs.

Some alpha-blockers are more commonly prescribed to patients than others. A doctor will need to assess the patient on an individual basis. This will help the doctor determine what the best alpha-blocker will be for the patient.

There are short-acting alpha-blockers, as well as long-acting options.
A short-acting alpha-blocker starts to work quickly after the patient takes the drug. The problem, however, is that the effects are short-lived. Blood pressure will be reduced only for a couple of hours.

A long-acting alpha-blocker takes a longer period before the effects can be observed. The good thing about long-acting alpha-blockers is the fact that these drugs provide results that last for longer.

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What Conditions Are Alpha Blockers Used For?

Hypertension is the most common condition that is treated with alpha-blockers. Hypertension, or high blood pressure, is a severe condition. In many cases, the patient does not experience early symptoms. The condition gradually causes blood vessel walls to be damaged. In turn, it increases the risk of heart disease.

The improved dilation of blood vessels provided by alpha-blockers is a significant effect. It reduces the pressure that is placed on blood vessel walls. It also helps to boost blood flow, which ensures cells and tissue through the person’s body gets adequate oxygen and nutrients.

In the majority of cases, alpha-blockers are not used alone as a treatment for hypertension. A doctor will often need to prescribe additional drugs for the patient. A diuretic will usually be prescribed alongside the alpha-blocker. This is generally the case when the patient has hypertension that seems to be hard to treat and control effectively.

Other conditions are sometimes treated with alpha-blockers. In men, alpha-blockers are sometimes used as a treatment for an enlarged prostate. This is a condition commonly known as benign prostatic hyperplasia.

Alpha-blockers are not always used only as a treatment for benign prostatic hyperplasia. If a man is suspected to be at a high risk of an enlarged prostate, the doctor may also prescribe an alpha-blocker for the patient. This will act as a preventative strategy.

Symptoms of benign prostatic hyperplasia may be improved with alpha-blockers. This is because these drugs may also relax muscles in specific areas of the urinary tract. The bladder neck tends to relax with alpha-blockers. The restriction in the urethra may also ease up.

What Types Of Alpha Blockers Are Used For BPH?

Different types of alpha-blockers can be used to help men with benign prostatic hyperplasia. Not all alpha-blockers that are available on the market will be helpful for an enlarged prostate.

Doxazosin, Terazosin, and Prazosin are commonly used to treat high blood pressure. Men with benign prostatic hyperplasia, however, will generally need a different type of alpha-blocker. This is because these drugs tend to work only on the walls of smaller arteries.

Certain alpha-blockers work on more than just muscles in the arteries. These may help to provide a relaxation of the muscle that is found in the bladder’s neck.

Several Alpha-blockers have been approved by the FDA to be prescribed to patients with an enlarged prostate. These drugs primarily work on the lower urinary tract symptoms a patient experiences.

The drugs that have been approved include3:

Flomax tamsulosin is the most common alpha-blocker used for men with benign prostatic hyperplasia. This alpha-blocker was specifically developed for men with an enlarged prostate. Flomax is a brand name drug that contains Tamsulosin as an active ingredient4.

What Side Effects Do Alpha Blockers Have?

Even though alpha-blockers can provide a reduction in blood pressure and help with benign prostatic hyperplasia, there are side-effects that patients should learn about. These side-effects can sometimes be unpleasant. Some side-effects can interfere with the patient’s day-to-day tasks. Some side-effects can become a severe problem in a person’s life.

We outline some of the most essential side-effects that patients should be aware of. This allows the individual to understand what they should expect when they take an alpha-blocker.

It should be noted that not everyone will experience side-effects. Some people will also only experience mild side-effects. Others, however, may find that the drug affects them adversely at a more significant level.


One of the most common side-effects that people experience when they take alpha-blockers is dizziness. This side-effect is often referred to as vertigo too. The dizziness is sometimes accompanied by nausea. These are all symptoms related to balance.

When balance is thrown off due to the use of drugs, the person may find that they are unable to continue with a task they are busy with. Studies have found that a large number of drugs can cause dizziness as a side-effect5. Alpha-blockers only make up a single category of such medications.


While not a very common side-effect, patients taking alpha-blockers need to understand that there is a risk of fainting too. It is also important to note that this is considered a more serious side-effect.

There are various reasons why fainting may occur in people who take alpha-blockers. Dizziness may become severe and cause fainting. It is also possible to faint when the drug causes blood pressure levels to decline too much.

Low Blood Pressure

The main action of alpha-blockers is to reduce blood pressure. When a patient is provided with a dose that is too strong, there is a risk of experiencing low blood pressure.

There are also cases where interaction with another drug or supplement may cause low blood pressure. Low blood pressure is also known as hypotension. This is when blood pressure levels decline too much. This can be a serious side-effect. In some cases, it may cause the patient to faint.

Dizziness may also be a sign of low blood pressure, as well as nausea.
Other symptoms that may indicate low blood pressure include6:

  • Dehydration

  • Unusual thirst

  • Poor concentration

  • Blurry vision

  • Shallow breathing

  • Rapid breathing

  • Fatigue

  • Pale skin

The patient’s skin may also become clammy and cold. In some cases, the patient may also experience symptoms generally associated with depression.

Sexual Side-Effects

A lot of men who take Flomax and other alpha-blockers for benign prostatic hyperplasia bph tend to experience side-effects that affect their sexual health. Several types of sexual side-effects may occur in men.

When looking at the effects of alpha-blockers, it seems like these drugs may improve erectile function. There are, however, some cases where the erectile function may be adversely affected. The man may then experience erectile dysfunction.

This is generally the case when the man experiences a drop in blood pressure when they take alpha blockers7. A significant decline in blood pressure leads to a reduction in filling pressure within the penis. In turn, not enough blood enters the penis during an erection. This may lead to a poor erection that is not fully rigid.

In one study, 1.6% of patients taking Terazosin experienced impotence as a side-effect3.

Other sexual side-effects may occur, including problems with ejaculation. Some men may experience retrograde ejaculation when they take alpha-blocker medications.

Retrograde ejaculation is a condition where semen does not come out at the tip of the penis when a man ejaculates. Instead, the semen is sent in the wrong direction.

In such a case, semen enters the patient’s bladder. This isn’t a particularly harmful side-effect. Retrograde ejaculation has been linked to infertility, however. Men with retrograde ejaculation are sometimes said to experience dry orgasms.

Sinus Symptoms

Some patients have reported experiencing symptoms associated with sinus when they take alpha-blockers. This is also among some of the more common side-effects that patients tend to experience.

The drug may cause the patient to experience a runny nose. In some cases, patients rather experience a stuffy nose. There are also scenarios where the patient finds that they continuously sneeze while taking the alpha-blocker medication.

Congestion is another sinus-related side-effect that seems to be rather common.

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Natural Alternatives To Flomax

Flomax and other drugs for benign prostatic hyperplasia may cause unpleasant symptoms. This is why a lot of men are looking for natural Flomax alternatives. There are a few researched natural ingredients that may help in the treatment of an enlarged prostate.

When looking at natural remedies, there are a few different options available.

Some natural products aim to help reduce the size of the prostate. This is often done by blocking the conversion of testosterone to dihydrotestosterone. The dihydrotestosterone hormone has been shown to contribute to an enlargement of the prostate.

There are also a few natural products that aim to relieve the lower urinary tract symptoms a man may experience. These generally cause the bladder neck muscle to relax. In turn, the man may find that urination becomes easier. There may also be fewer problems like urinary incontinence and urinary retention. This is useful for chronic and acute urinary retention.

  • Saw Palmetto is one of the most researched options for men with benign prostatic hyperplasia. It is a fruit that grows on a palm tree. Several urinary symptoms may be relieved with the use of a saw palmetto supplement. The NIH reports that there are a few studies that show saw palmetto is effective for an enlarged prostate8.
  • Beta-sitosterol has also been shown to be useful for men with BPH symptoms. The compound is also known as phytosterols. Sometimes it may be called sitosterols. Studies have confirmed that beta-sitosterol is effective at relieving symptoms linked to BPH9. These supplements may improve urine flow. Other symptoms could also be relieved.

  • Other options that men may also consider trying include Pygeum and Rye Grass Pollen Extract. Both of these may help to reduce the urinary symptoms that are caused by benign prostatic hyperplasia.

  • There are cases where Stinging Nettle Root Extract helped men with an enlarged prostate too. The ingredient relieves symptoms associated with BPH. The current evidence behind the Stinging Nettle Root Extract is still somewhat limited. Thus, further studies are still needed to produce more accurate results.


Alpha-blockers are commonly prescribed to patients with hypertension. In men, these drugs are sometimes also used to treat benign prostatic hyperplasia. The drug does provide effective results. It also causes some unpleasant side-effects, however.

Patients should understand the side-effects that may occur when they take an alpha-blocker drug. This ensures the patient knows what to expect. Natural alternatives to Flomax and other alpha-blockers are available too.


  1. Cardiology Explained. (2004) Chapter 6: Hypertension. [online] Available at: https://www.ncbi.nlm.nih.gov/books/NBK2217/
  2. Clinical Cardiology. (1990) Alpha-adrenergic blockers: mechanism of action, blood pressure control, and effects of lipoprotein metabolism. [online] Available at: https://www.ncbi.nlm.nih.gov/pubmed/1980236
  3. Reviews in Urology. (2007) Alpha-Blockers for the Treatment of Benign Prostatic Hyperplasia. [online] Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2213889/
  4. Drugs.com. (2019) Flomax. [online] Available at: https://www.drugs.com/flomax.html
  5. Journal of Pharmacology & Pharmacotherapeutics. (2013) Vertigo/dizziness as a Drugs’ adverse reaction. [online] Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3853661/
  6. American Heart Association. Low Blood Pressure – When Blood Pressure Is Too Low. [online] Available at: https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/low-blood-pressure-when-blood-pressure-is-too-low
  7. Reviews in Urology. (2005) Sexual Function and a-Blockers. [online] Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1477634/
  8. National Institutes of Health. Saw Palmetto. [online] Available at: https://www.nccih.nih.gov/health/saw-palmetto/
  9. MDPI Nutrients. (2013) Fatty Acid and Phytosterol Content of Commercial Palmetto Supplements. [online] Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3798925/

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