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Terazosin, Oral Capsule

Highlights for terazosin

  1. Terazosin oral capsule is available only as a generic drug.
  2. 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.
  3. 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.
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Important warnings

Important warnings

  • 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.

About

What is terazosin?

Terazosin oral capsule is a prescription drug that’s only available as a generic 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.

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.

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.

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

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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Side effects

Terazosin side effects

Terazosin oral capsule 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. Terazosin can also cause other side effects.

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 911 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.

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.

Interactions

Terazosin may interact with other medications

Terazosin oral capsule can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with terazosin are listed below.

Blood pressure drug

When taken with terazosin, this blood pressure drug may cause very low blood pressure.

  • verapamil

Erectile dysfunction (ED) drugs

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

  • avanafil
  • 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.

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Other warnings

Terazosin warnings

Terazosin oral capsule comes with several warnings.

Allergy warnings

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.

Warnings for people with certain health conditions

For 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.

For 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.

For 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.

Warnings for other groups

For 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.

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

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Dosage

How to take terazosin

This dosage information is for terazosin 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

Forms and strengths

Generic: terazosin

  • Form: Oral capsule
  • Strengths: 1 mg, 2 mg, 5 mg, 10 mg

Dosage for benign prostatic hyperplasia

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.

Senior dosage (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.

Dosage for high blood pressure (hypertension)

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.

Senior dosage (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.

Special considerations

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 any other drug you take for high blood pressure may need to be changed. Talk to your doctor for more information.

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.

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Take as directed

Take as directed

Terazosin oral capsule is used for long-term treatment. It 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 911 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.

Important considerations

Important considerations for taking terazosin

Keep these considerations in mind if your doctor prescribes terazosin oral capsule for you.

General

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.

Storage

  • 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.

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Alternatives

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.

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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