Terazosin (By mouth)

Terazosin (ter-AZ-oh-sin)

Treats high blood pressure and benign prostatic hyperplasia (enlarged prostate). This medicine is an alpha blocker.

Brand Name(s):

When This Medicine Should Not Be Used:

How to Use This Medicine:

Capsule, Liquid, Tablet, Liquid Filled Capsule

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
• Oral liquid: Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
• Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Some medicines can affect how terazosin works. Tell your doctor if you are using verapamil, medicine to treat erectile dysfunction (including sildenafil, tadalafil), or other blood pressure medicines.

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have liver disease, cataracts, low blood pressure, or a history of prostate cancer.
• This medicine may cause the following problems:
  • Low blood pressure (especially if taken with other medicines that lower blood pressure)
  • Painful or prolonged erection of the penis
  • Serious eye problem called Intraoperative Floppy Iris Syndrome (IFIS) in patients having an eye procedure (including cataract surgery)
• This medicine could lower your blood pressure too much, especially when you first use it. This can make you dizzy or lightheaded. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. Stand or sit up slowly if you feel lightheaded or dizzy.
• Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Chest pain
• Fever, chills, sore throat, body aches
• Lightheadedness or fainting
• Numbness or tingling in the hands or feet
• Painful or prolonged erection of your penis
• Rapid weight gain, swelling in your hands, ankles, or feet
• Slow, fast, or irregular heartbeat

If you notice these less serious side effects, talk with your doctor:

• Arm or leg pain, back pain
• Blurred vision
• Inability to have or keep an erection, loss in sexual ability, desire, drive, or performance
• Lack or loss of strength
• Sleepiness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 3/4/2025