Medically Reviewed on 2/16/2023

Generic Name: terazosin

Brand Name: Hytrin

Drug Class: Alpha Blockers, Antihypertensives

What is terazosin, and what is it used for?

Terazosin is a prescription medication used to treat the symptoms of urinary obstruction due to an enlarged prostate caused by benign prostatic hypertrophy (BPH). Terazosin also is used alone or in combination with another blood pressure medication to treat high blood pressure.

Terazosin is that belongs to a class of medications called alpha 1 blockers, which relax the smooth muscles of the arteries, the prostate, and the bladder neck.

What are the side effects of terazosin?

Commonly reported side effects of terazosin include:

By relaxing the smooth muscles and dilating the arteries, terazosin can cause a marked lowering of blood pressure especially when the patient stands up (orthostatic or postural hypotension). Postural hypotension can cause the patient to faint upon standing. Postural hypotension and fainting usually are associated with the first dose or the first few days of treatment. Hypotension and fainting also can occur when doses of medication are increased abruptly or another blood pressure medication is added. In order to decrease the likelihood of excessive hypotension and fainting, terazosin is initiated low doses.

Prostate cancer and prostatic hypertrophy both cause similar symptoms of obstruction to the flow of urine. Prostate cancer and prostatic hypertrophy can co-exist. Therefore, patients being treated for prostate hypertrophy should be evaluated to exclude the presence of prostate cancer.

What is the dosage for terazosin?

  • Terazosin may be taken with or without food.
  • The recommended starting dose for treating BPH is 1 mg daily.
  • The dose should be increased a step up to 10 mg daily, which is the effective dose for most patients. Some patients may show additional improvement with a 20 mg dose.
  • For high blood pressure, the recommended dose is 1 to 5 mg once daily. Some patients may benefit from doses as high as 20 mg per day.
  • Terazosin also may be administered twice daily.


The prostate is about the size of a _____________. See Answer

What drugs interact with terazosin?

  • PDE-5 inhibitors used primarily for erectile dysfunction (for example, vardenafil [Levitra, Staxyn], Adcirca, tadalafil [Cialis], sildenafil [Viagra, Revatio) add to the blood pressure lowering effects of terazosin and may result in orthostatic or postural hypotension. (See Side Effects.)
  • Individuals who take terazosin should be on a stable dose before a PDE-5 inhibitor is started, and the PDE-5 inhibitor should be started at the lowest dose. If the patient is already taking a PDE-5 inhibitor terazosin should be started at the lowest dose.

Is terazosin safe to use during pregnancy or while breastfeeding?

  • There are no adequate studies of terazosin in pregnancy. It is not recommended during pregnancy unless the benefits justify the potential but unknown risks to the fetus
  • It is not known whether terazosin is excreted in breast milk.

What else should I know about terazosin?

What preparations of terazosin are available?

Tablets or Capsules: 1, 2, 5, and 10 mg.

How should I keep terazosin stored?

Terazosin should be stored at room temperature below 86 F (30 C) in a tight container.

How does terazosin work?

Terazosin is part of a class of alpha blockers. Alpha blockers include doxazosin (Cardura), alfuzosin (Uroxatral), tamsulosin (Flomax), and prazosin (Minipress) relaxing the smooth muscles of the arteries to lower blood pressure. Relaxing the smooth muscles around the bladder neck relieves urinary obstruction caused by an enlarged prostate (prostate hypertrophy). Terazosin relaxes the smooth muscles of the bladder neck and the prostate, increasing urine flow.

When was terazosin approved by the FDA?

The FDA approved terazosin in 1987.


Terazosin is a medication prescribed for the treatment of the symptoms of urinary obstruction due to an enlarged prostate caused by BPH (benign prostatic hypertrophy). Terazosin is also used alone or in combination with another blood pressure medication for the treatment of high blood pressure. Commonly reported side effects of terazosin include postural hypotension, dizziness, weakness, fatigue, headaches, swelling of the legs (edema), palpitations, nasal congestion, sleepiness, decreased libido, impotence, and blurred vision.

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See more info: terazosin on RxList
Medically Reviewed on 2/16/2023
Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine


FDA Prescribing Information