Uses

What is terazosin used for?

Terazosin is commonly used to treat benign prostatic hyperplasia (BPH), a condition where the prostate gland is enlarged but not cancerous. An enlarged prostate may lead to trouble with urination. 

Terazosin is also commonly used to treat high blood pressure (hypertension).

Terazosin may also be used for other conditions as determined by your healthcare provider.

How does terazosin work (mechanism of action)?

Terazosin is an alpha blocker. It works to relax certain muscles in your body.

For BPH, terazosin works to relax certain muscles in your prostate and bladder. This improves the flow of urine and reduces the symptoms of BPH.

For high blood pressure, terazosin works to relax certain muscles in your blood vessels. This makes your blood vessels more open and lets blood move through them more easily, which lowers blood pressure.

How is terazosin supplied (dosage forms)?

Terazosin is available in the following dosage forms that are taken by mouth.

  • 1 mg oral capsules
  • 2 mg oral capsules
  • 5 mg oral capsules
  • 10 mg oral capsules

How should I store terazosin?

Store terazosin at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place that is away from moisture and out of direct sunlight.

Side Effects

What are the most common side effects of terazosin?

The most common side effects of terazosin are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Dizziness
  • Headache
  • Tiredness or feeling weak
  • Drowsiness
  • Stuffy nose
  • Blurry vision
  • Nausea
  • Puffiness of your hands or feet (edema)

There may be other side effects of terazosin that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of terazosin?

While less common, the most serious side effects of terazosin are described below, along with what to do if they happen.

Severe Allergic Reactions. Terazosin may cause allergic reactions, which can be serious. Stop taking terazosin and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Low Blood Pressure Upon Standing (Orthostatic Hypotension). Terazosin may cause a sudden drop in blood pressure when standing up from a seated or lying position. This may result in dizziness or fainting, especially when you start treatment or after dose increases. To help prevent this side effect, your healthcare provider may tell you to take your first dose of terazosin at bedtime. Tell your healthcare provider right away if you have any of the following symptoms of orthostatic hypotension with terazosin.

  • Dizziness, feeling lightheaded, or fainting upon standing
  • Blurred vision
  • Confusion
  • Feeling weak
  • Feeling like your heart is racing or skipping (palpitations)

Painful, Prolonged Erection (Priapism). Terazosin may cause an unwanted erection that is persistent, painful, and that may occur without sexual arousal. Priapism may cause permanent damage to the penis. Stop taking terazosin and get emergency help right away if you have any of the following symptoms. 

  • Erection lasting for more than 4 hours 
  • Erection that is unrelated to sexual stimulation
  • Painful or tender penis

Warnings & Precautions

Who should not use terazosin?

Allergies to Ingredients. People who are allergic to any of the following should not use terazosin.

  • Hytrin
  • Terazosin
  • Terazosin HCl
  • Terazosin hydrochloride
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific terazosin products they stock.

What should I know about terazosin before taking it?

Do not take terazosin unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share terazosin with other people, even if they have the same condition as you. It may harm them.

Keep terazosin out of the reach of children.

Terazosin may cause dizziness or drowsiness. Do not drive or do other activities that require alertness and coordination for at least 12 hours after your first dose or after your dose is increased. Wait to drive or do other activities that require coordination until you know how terazosin affects you.

People who are age 65 and older can be at greater risk for some side effects from terazosin. Talk to your healthcare provider about your risks if you are in this age group.

Terazosin is commonly used to treat benign prostatic hyperplasia (BPH), which is non-cancerous enlargement of the prostate. In some cases, BPH can occur at the same time as prostate cancer. Your healthcare provider may recommend getting tested for prostate cancer before you start terazosin and getting regular screenings thereafter. 

What should I tell my healthcare provider before taking terazosin?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if terazosin is right for you.

In particular, make sure that you discuss any of the following.

Planned Eye Surgery. Terazosin may raise the risk of eye problems called intraoperative floppy iris syndrome during or after cataract or glaucoma surgery. Tell your healthcare provider if you are planning to have eye surgery. They may recommend that you wait until after the surgery is over to start terazosin.

Other Medicines and Supplements. Terazosin may interact with other medicines and supplements. Before taking terazosin, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if terazosin could affect pregnancy or if it could harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take terazosin while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if terazosin passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does terazosin interact with foods or drinks?

There are no known interactions between terazosin and foods or drinks.

It is unknown if drinking alcohol will affect terazosin. The risk of side effects, such as dizziness, may be higher if you drink alcohol while taking terazosin.

Does terazosin interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are taking any of the following before taking terazosin. 

  • A medicine for high blood pressure, such as verapamil (Verelan)
  • A type of medicine called a phosphodiesterase-5 (PDE-5) inhibitor, such as avanafil (Stendra), sildenafil (Viagra, Revatio, and others), tadalafil (Cialis and others), or vardenafil (Levitra, Staxyn), which are used for erectile dysfunction and pulmonary arterial hypertension (PAH)

This may not be a complete list of medicines that can interact with terazosin. Always check with your healthcare provider.

Does Terazosin interact with other drugs you are taking?
Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much terazosin?

If you or someone else has used too much terazosin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of terazosin?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses. 

If you miss doses of terazosin for several days in a row, check with your healthcare provider before taking it again. They may recommend a lower dose to help prevent side effects until your body readjusts to the medicine.

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