Terazosin | Side Effects, Dosage, Uses & More
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Generic Name:

terazosin, Oral capsule

All Brands

  • Hytrin (Discontinued)
A discontinued drug is a drug that has been taken off the market due to safety issues, shortage of raw materials, or low market demand.
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Highlights for terazosin

Oral capsule
1

Terazosin is used to improve urinary flow and other symptoms of benign prostatic hyperplasia (BPH) in men. It is also used to treat high blood pressure in men and women.

2

This drug is available only as a generic medication. It comes in the form of a capsule taken by mouth.

3

Your doctor will start your treatment with 1-mg capsules. Your dose may be gradually increased as your body gets used to the drug.

4

This medication can cause a sudden drop in blood pressure. You may feel dizzy, faint, or lightheaded. This typically occurs when you stand up after lying down or sitting.

5

Terazosin may cause a painful erection of the penis that lasts for hours (priapism). If you have an abnormal erection, go to the nearest emergency room right away.

IMPORTANT INFORMATION

Low blood pressure

Terazosin can cause a sudden drop in blood pressure. This typically occurs when you stand up after lying down or sitting. This is called postural hypotension. You may feel dizzy, faint, or lightheaded. It can occur anytime while you are taking this drug. However, it is more likely to occur right after your first dose and during the first 7 days of treatment.

Painful erection

This drug may cause a painful erection of the penis that lasts for hours (priapism). If you have an abnormal erection, go to the nearest emergency room right away. If left untreated, this condition can lead to impotence (a permanent inability to have an erection).

Cataract surgery

If you are going to have cataract surgery, be sure to tell your doctor that you are taking this drug. Intraoperative floppy iris syndrome (IFIS) can occur during this surgery in people taking terazosin. IFIS causes problems with the iris of the eye.

What is terazosin?

Terazosin is a prescription drug. It comes in the form of a capsule taken by mouth. This medication is available as a generic drug. Generic drugs usually cost less than brand-name drugs.

Terazosin may be used as part of a combination therapy. That means you may need to take it with other drugs.

If you’re taking this drug to treat BPH, you should see your symptoms start to improve within 2 to 4 weeks. If you’re taking it to treat high blood pressure, you should notice a change right away if you are monitoring your blood pressure.

Why it's used

Terazosin is used to improve urinary flow and other symptoms of benign prostatic hyperplasia (BPH) in men. It is also used to treat high blood pressure in men and women.

How it works

Terazosin belongs to a drug class called alpha-blockers (alpha-1-selective adrenoceptor blockers).

More Details

How it works

Terazosin belongs to a drug class called alpha-blockers (alpha-1-selective adrenoceptor blockers). A class of drugs refers to a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Terazosin works by relaxing the muscles in your bladder and prostate to improve urine flow. It also widens blood vessels in your body so blood can flow through more easily. This helps lower your blood pressure.

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terazosin Side Effects

Oral capsule

Most Common Side Effects

The more common side effects that occur with terazosin include:

  • Weakness

  • Low blood pressure. Symptoms can include:

    • dizziness, especially when standing after lying down or sitting
  • Drowsiness

  • Stuffy or runny nose

  • Impotence (inability to have an erection)

  • Blurred or hazy vision

  • Nausea

  • Swelling or puffiness in hands, feet, or lower legs

  • Increased heart rate

  • Urinary tract infection. Symptoms may include:

    • burning feeling when you urinate
    • cloudy or strange-smelling urine
    • pressure in your stomach/lower abdominal area
    • fever
    • tiredness

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Allergic reaction. Symptoms can include:

    • rash
    • fever
    • shortness of breath
  • Priapism (painful erection of the penis that lasts for hours)

  • Low blood platelet count (thrombocytopenia)

  • Irregular heartbeat (atrial fibrillation)

  • Intraoperative floppy iris syndrome (IFIS). This condition can occur during cataract surgery. It causes problems with the iris of your eye. If you are going to have cataract surgery, tell your doctor that you are taking an alpha blocker.

Pharmacist's Advice
Healthline Pharmacist Editorial Team

Terazosin can cause a sudden drop in blood pressure. This typically occurs when you stand after lying down or sitting. It is called postural hypotension. You may feel dizzy, faint, or lightheaded. It can occur anytime while you are taking this drug. However, it is more likely to occur right after your first dose and during the first 7 days of treatment.

If you have postural hypotension, sit or lie down again. To help prevent it, take this drug at bedtime if you are taking it once a day. Also, be sure to move slowly while standing up after sitting or lying down.

Terazosin doesn’t usually cause drowsiness.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
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terazosin May Interact with Other Medications

Oral capsule

Terazosin can interact with other medications, herbs, or vitamins you might be taking. An interaction is when a substance changes the way a drug works. This can be harmful, or keep the drug from working as well as it should. To help prevent drug interactions, your doctor should manage all of your medications carefully. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Alcohol interaction

Having drinks that contain alcohol while taking terazosin can cause your blood pressure to be too low.

Medications that might interact with this drug

Blood pressure drugs

When taken with terazosin, other blood pressure drugs may cause very low blood pressure. These drugs include:

  • atenolol
  • propranolol
  • hydrochlorothiazide
  • verapamil

Erectile dysfunction (ED) drugs

When taken with terazosin, drugs to treat ED can cause very low blood pressure. These drugs include:

  • sildenafil
  • tadalafil
  • vardenafil

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Terazosin warnings
allergies
People with allergies

You should not take this drug if you have had an allergic reaction to terazosin or any ingredient in the terazosin capsule. Talk to your pharmacist if you have questions about your allergies and taking this drug.

low blood pressure
People with low blood pressure (hypotension)

If you are using this drug for benign prostatic hypertrophy and also have low blood pressure, terazosin may lower your blood pressure even more.

low platelet count
People with low platelet count (thrombocytopenia)

This drug has caused low platelet count in the blood of some patients. If you already have this condition, taking this drug could make it worse. While you are taking this drug, your doctor may monitor your platelet count through blood tests.

risk of falls
People with risk of falls

If you are at risk of falls, the low blood pressure that can occur when taking this drug can increase your fall risk. Factors that put you at risk of falls include being a senior (ages 65 years and older), having osteoporosis, and having problems with balance. To help reduce your fall risk, take this drug at bedtime if you are taking it once a day. Also, be sure to move slowly when standing after sitting or lying down.

pregnant woman
Pregnant women

Terazosin is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should only be used if the potential benefit justifies the potential risk to the fetus.

breast-feeding
Women who are breast-feeding

It is not known if this drug passes into breast milk. Talk to your doctor about whether you should take this drug while breastfeeding.

allergies
Allergies

You should not take this drug if you have had an allergic reaction to terazosin or any ingredient in the terazosin capsule. Talk to your pharmacist if you have questions about your allergies and taking this drug.

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How to Take terazosin (Dosage)

Oral capsule

All possible dosages may not be included here. Your doctor will tell you what dosage is right for you. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Benign prostatic hyperplasia
Form: Oral capsule
Strengths: 1 mg, 2 mg, 5 mg, 10 mg
Adult dosage (ages 18 years and older)
  • The initial dose is 1 mg at bedtime. Your doctor may gradually increase your dose to 2 mg, 5 mg, or 10 mg. Any increase in your dose will depend on how your body responds to the medication.
  • If you are at the 10-mg daily dose, your doctor will want to wait at least 4–6 weeks before increasing the dose. This will help confirm whether the drug is working. After that time, the dose can be increased to 20 mg if needed.
  • If you stop taking this drug for several days, be sure to restart the medication at 1 mg/day. Do not stop taking this drug without talking to your doctor first.
Child dosage (ages 0–17 years)

Dosage for people younger than 18 years has not been established.

Special considerations

High blood pressure: Taking terazosin at the same time as other medications that lower blood pressure can cause very low blood pressure. The dosage of either terazosin or the other drug may need to be changed. Talk to your doctor for more information.

Senior (ages 65 years and older): The lowered blood pressure that can occur with posture changes when taking this drug can increase your fall risk. To help reduce your risk of falls, take this drug at bedtime if you are taking it once a day. Also, be sure to move slowly when standing after sitting or lying down.

High blood pressure (hypertension)
Form: Oral capsule
Strengths: 1 mg, 2 mg, 5 mg, 10 mg
Adult dosage (ages 18 years and older)
  • The initial dose is 1 mg one time per day. This can be increased gradually to 2 mg, 5 mg, 10 mg, or 20 mg. Depending on your blood pressure, your dose may be given once a day or twice a day.
  • Doses over 20 mg do not lower blood pressure any further.
  • You can help determine whether changes to your dosage are needed. These could be a change in your dose amount, or a change from taking this drug once a day to twice a day. Do this by checking your blood pressure right before your next dose, and again 2–3 hours after that dose.
  • If you stop taking this drug for several days, be sure to restart the medication at 1 mg/day. Do not stop taking this drug without talking to your doctor first.
Child dosage (ages 0–17 years)

Dosage for people younger than 18 years has not been established.

Special considerations

High blood pressure: Taking terazosin at the same time as other medications that lower blood pressure can cause very low blood pressure. The dosage of either terazosin or the other drug may need to be changed. Talk to your doctor for more information.

Senior (ages 65 years and older): The lowered blood pressure that can occur with posture changes when taking this drug can increase your fall risk. To help reduce your risk of falls, take this drug at bedtime if you are taking it once a day. Also, be sure to move slowly when standing after sitting or lying down.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Terazosin comes with serious risks if you don't take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all

If you’re taking this drug to treat benign prostatic hyperplasia (BPH), your symptoms may worsen. These symptoms include an urgent need to urinate, and a weak urine stream.

If you’re taking it to treat high blood pressure, your blood pressure may increase.

If you miss doses or don’t take the drug on schedule

Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much

You may get very low blood pressure. Symptoms include feeling very dizzy, faint, or lightheaded, or passing out. If you have symptoms of very low blood pressure, call 9-1-1 or go to the emergency room right away for treatment.

What to do if you miss a dose

Call your doctor for guidance on how you should restart this drug.

How to tell if the drug is working

If you’re taking this drug to treat BPH, your urinary flow should improve.

If you’re taking it to treat high blood pressure, your blood pressure should go down. Your doctor can check your blood pressure, or you can do it using a home blood pressure monitor.

Terazosin is a long-term drug treatment.

If taking this drug once a day, take it at bedtime

If you are taking this medication once a day, take it at bedtime to avoid side effects such as a sudden drop in blood pressure. Take it every day as your doctor prescribes.

Terazosin must be stored at the right temperature

Store terazosin at room temperature between 68°F (20°C) and 77°F (25°C). Do not freeze this drug.

Keep this drug away from light.

Do not store this medication in moist or damp areas such as bathrooms.

Travel

When traveling with your medication:

  • Always carry your medication with you, such as in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Be sure to carry with you the prescription-labeled box that your medication came in.

Clinical monitoring

To make sure that terazosin is safe for you to take, your doctor may monitor the following before you begin treatment and regularly during treatment:

  • blood pressure
  • heart rate
  • blood cell counts
  • symptoms of benign prostatic hypertrophy

When you have an enlarged prostate, you are at risk of prostate cancer. Your doctor may also check your levels of prostate-specific antigen (PSA) to check for prostate cancer.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other options that may work for you.

What does the pill look like?

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How Much Does terazosin Cost?

Oral capsule

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These prices represent the lowest priced national pharmacies for terazosin on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on August 25, 2015

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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