Terazosin is used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH), which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. It also is used alone or in combination with other medications to treat high blood pressure. Terazosin is in a class of medications called alpha-blockers. It relieves the symptoms of BPH by relaxing the muscles of the bladder and prostate. It lowers blood pressure by relaxing the blood vessels so that blood can flow more easily through the body.
Terazosin comes as a capsule to take by mouth. It is usually taken with or without food once a day at bedtime or twice a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take terazosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Your doctor will start you on a low dose of terazosin and gradually increase your dose. If you stop taking terazosin for a few days or longer, call your doctor. Your doctor usually will start you again on the lowest dose of terazosin and gradually increase your dose.
Terazosin controls high blood pressure and the symptoms of BPH but does not cure them. It may take 4 to 6 weeks or longer before you feel the full benefit of terazosin for BPH. Continue to take terazosin even if you feel well. Do not stop taking terazosin without talking to your doctor.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking terazosin,
- tell your doctor and pharmacist if you are allergic to terazosin, doxazosin (Cardura, Cardura XL), prazosin (Minipress, in Minizide), or any other medications.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: medications for erectile dysfunction (ED) such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra);and other medications for high blood pressure, especially verapamil (Calan, Covera, Isoptin, Verelan). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have or have ever had prostate cancer.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking terazosin, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking terazosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken terazosin.
- you should know that terazosin may make you drowsy or dizzy. Do not drive a car, operate machinery or perform dangerous tasks for 12 hours after the first time you take terazosin or after your dose is increased, and until you know how this medication affects you.
- you should know that terazosin may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking terazosin, when your dose is increased, or when treatment with terazosin is stopped for several days and then restarted. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. If you experience these symptoms, sit or lie down. If these symptoms do not improve, call your doctor.
Follow your doctor's directions for your meals, including advice for a reduced salt (sodium) diet .
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. Check with your doctor if you have missed two or more doses.
Terazosin may cause side effects. Tell your doctor if any of these symptoms or those listed in the SPECIAL PRECAUTIONS section are severe or do not go away:
- stuffy or runny nose
- back pain
- weight gain
- decreased sexual ability
- blurred vision
- swelling of the hands, feet, ankles, or lower legs
- pain, burning, numbness, or tingling in the hands or feet
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:
- shortness of breath
- rapid, pounding, or irregular heartbeat
- painful erection of the penis that lasts for hours
Terazosin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light and excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include:
- blurred vision
Keep all appointments with your doctor. Your blood pressure should be checked regularly to determine your response to terazosin.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Last Reviewed: September 1, 2010.