Terazosin

Last Reviewed: Dec 19, 2024

Warnings

Terazosin Risks, Warnings, and Complications

Terazosin can cause serious health complications in certain high-risk individuals. Talk to your doctor or pharmacist about other treatment options for BPH or high blood pressure if you are at an increased risk of health complications from this drug. Some of the risks of taking terazosin include:

POSTURAL HYPOTENSION: Terazosin and other alpha-adrenergic blockers can cause a significant lowering of blood pressure, especially with changes in position. This sudden drop in blood pressure is called postural hypotension, and it can lead to syncope (fainting). The risk of low blood pressure is highest with the first dose and in the first few days of treatment. It can also occur if terazosin therapy is interrupted and then restarted. Other risk factors include a rapid dose escalation, the use of other antihypertensive drugs that also have blood pressure-lowering effects, and hot weather or exercise. Sometimes, a fainting episode is preceded by supraventricular tachycardia, a type of heart rhythm abnormality where the heart rate can increase to 120 to 160 beats per minute.
To lower the risk of postural hypotension and fainting, your doctor will start you on a 1 mg daily dose of terazosin at bedtime. They will increase the dose slowly and add additional blood pressure medicines with caution. You should avoid driving and other potentially hazardous tasks until you know how the medicine affects you.
Also, arise slowly from a sitting or lying position to standing. If you experience lightheadedness or fainting, lie down and rest. Tell your doctor if you develop dizziness, lightheadedness, a fast heartbeat, or fainting while on terazosin. These effects typically occur within 90 minutes of taking a terazosin dose and are most common in the first 7 days of treatment, but can occur at any time. If you develop low blood pressure, your doctor may adjust your dose.
INTRAOPERATIVE EYE PROBLEMS: Terazosin and other alpha adrenergic blockers can cause a complication called intraoperative floppy iris syndrome during cataract surgery. Tell your eye surgeon you are taking terazosin before any planned eye surgery. They may ask you to stop terazosin temporarily and/or modify their surgical technique.
MASKED SYMPTOMS OF PROSTATE CANCER: BPH is a non-cancerous condition. However, it can cause many of the same symptoms as cancer of the prostate. Taking terazosin can therefore prevent a timely diagnosis of cancer by masking the symptoms. Your doctor may order a blood test called prostate-specific antigen (PSA) before starting you on terazosin to rule out cancer.
PRIAPISM: Terazosin and other drugs in its class can cause priapism, a painful or prolonged erection that lasts more than 4 hours and is unrelieved by masturbation or sexual intercourse. This condition requires immediate treatment to prevent permanent damage to the penis. Get emergency medical help if you develop a painful erection that does not go away.

Precautions Before Starting Terazosin

Tell your healthcare provider if you have ever had allergic reactions to terazosin, any of the active or inactive ingredients in terazosin capsules, other alpha-blocker drugs such as prazosin (Minipress) or doxazosin (Cardura), or any other medications. Your pharmacy can give you a list of ingredients.

Give your doctor and pharmacist a complete list of your medications, including prescription drugs, over-the-counter medicines, nutritional supplements, and herbal products. This can help avoid possible interactions between terazosin and your other medications.

Give your doctor a complete medical history. Terazosin may not be safe for people with certain health conditions. Tell your healthcare provider if you have a history of prostate cancer, kidney problems, kidney failure, heart disease, or heart failure.

Older adults (age 65 and above) should talk to their healthcare provider about the benefits versus risks of taking terazosin. There may be other safer medications available to treat high blood pressure.

Tell your healthcare provider if you are pregnant, could be pregnant, are planning a pregnancy, or are breast-feeding. There aren’t enough studies in humans to know whether the medication affects the unborn baby. Also, tell your doctor if you are breast-feeding. It is not known if terazosin passes into breast milk.

Precautions During Use of Terazosin

Keep all your medical and laboratory appointments during treatment with terazosin. Follow your doctor’s dosing instructions carefully.

Terazosin can cause dizziness and blurred vision. Be careful when driving and operating machinery until you know how this medicine affects you.

You may feel dizzy or lightheaded after taking terazosin, especially with changes in position. Stand up slowly from a sitting or lying position. Rest your feet on the floor for a few minutes before standing up when getting out of bed. If you feel dizzy, lie down and rest for a few minutes. These symptoms are most likely to occur after the first dose and in the first few days of therapy.

Tell all your healthcare providers that you are on terazosin before any surgery, including eye surgery and dental procedures.

Terazosin Drug Interactions

Certain other drugs can affect how terazosin works. Possible interactions between terazosin and other medicines can increase the risk of severe adverse reactions. The following medications can interact with terazosin:

Other blood pressure medications, especially calcium channel blockers such as verapamil
Phosphodiesterase-5 (PDE-5) inhibitors prescribed for erectile dysfunction, such as sildenafil (Viagra) and tadalafil (Cialis)

The above list does not describe all the potential interactions of terazosin. Give your doctor or pharmacist a list of all the medicines you are taking, including prescription drugs, nonprescription drugs, dietary supplements, and herbal remedies. Also, tell your healthcare professional if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription and over-the-counter medications.

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