Terazosin is a medication that’s typically used to treat difficulty urinating caused by an enlarged prostate (also known as benign prostatic hyperplasia or BPH). It can also be used to treat high blood pressure, but it’s not a first-choice option for this condition due to the risk of side effects, like feeling dizzy or weak, particularly for older adults. Terazosin is taken by mouth, typically once daily at bedtime. It’s only available as a lower-cost generic (former brand name Hytrin).
Terazosin is an alpha-1 blocker. It treats BPH by relaxing certain muscles in the prostate and bladder, which allows urine to flow more easily.
Terazosin can also treat high blood pressure by relaxing your blood vessels. This helps blood flow smoothly through the body.
| Common Brands | Hytrin |
|---|---|
| Drug Class | Alpha-1 blocker |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | Lower-cost generic available |
| Availability | Prescription only |
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Benign prostatic hyperplasia (BPH):
High blood pressure:
Contact your healthcare provider immediately if you experience any of the following.
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
More common
Dizziness
Less common
dizziness or lightheadedness when getting up from a lying or sitting position
fainting (sudden)
fast or irregular heartbeat
pounding heartbeat
shortness of breath
swelling of feet or lower legs
Rare
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Headache
unusual tiredness or weakness
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Terazosin can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Terazosin can cause you to feel dizzy or faint when you stand up after sitting or lying down. This is because your blood pressure may change quickly when you change positions (also known as orthostatic hypotension). The risk of this side effect is highest after your first dose. But it’s also more likely to happen during the first 7 days of taking terazosin and whenever your dose is raised. Typically, you tend to feel most dizzy within 90 minutes of taking a dose.
When you take terazosin for the first time or take a higher dose, avoid activities that could be dangerous for 12 hours after your dose. This includes driving, operating heavy machinery, and exercising. If you feel dizzy, lightheaded, or like your heart is pounding, make sure to stop doing anything that could be hazardous. If these symptoms are bothersome, let your healthcare provider know because they might need to change your dose.
In some rare cases, terazosin can cause a painful erection (also known as priapism) that continues for more than 4 hours. If this happens to you, contact your provider right away to avoid the risk of permanent erectile dysfunction.
If you take terazosin and plan to get cataract eye surgery, let your provider know. In some rare cases, this medication can cause changes to your iris, a condition called Intraoperative Floppy Iris Syndrome (IFIS). Keep in mind that terazosin is probably less likely to cause IFIS than other medications used to treat BPH, like tamsulosin. You don’t need to stop taking terazosin before the surgery, but your surgeon needs to adjust how they perform the operation. Letting your provider know ahead of time can help them prepare accordingly.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
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Terazosin is typically taken once daily at bedtime to lower your risk of falling. This is because terazosin can make you feel dizzy or light-headed, especially right after you take it. If you need to get up during the night, you may need more support than usual to safely get out of bed. To avoid falling, change positions slowly. It’s also helpful to have something to hold on to when you stand up. While dizziness is expected, let your provider know if this side effect is too bothersome or doesn’t get better after you’ve taken Terazosin for a week or two. They can talk with you about your options.
If you take Terazosin for BPH, your symptoms may start to improve in 2 to 4 weeks. You might notice that your urine stream is more consistent or that you can better empty your bladder. But if your symptoms aren’t getting better by then, let your provider know because they might need to raise your dose. Keep in mind that sometimes you may need to take your dose for 4 to 6 weeks to see the full effect. If you take Terazosin for high blood pressure, it can start to lower your blood pressure within 15 minutes after you take it. But it might take up to 2 to 3 hours for the medication to have the most effect. Your provider might tell you to check your blood pressure a few times a day, especially when you first start Terazosin, to see how it’s working.
While some medications that are used for BPH and high blood pressure can directly cause erectile dysfunction, this isn’t a known side effect of Terazosin. In some rare cases, Terazosin can cause priapism (prolonged erection), which can lead to erectile dysfunction if it’s not treated right away. If you experience painful erections that last for several hours, get medical help as soon as possible to avoid permanent damage.
Ask your provider if taking Terazosin and sildenafil (Viagra) is a possible option for you. Taking Terazosin and sildenafil (Viagra) at the same time can increase your risk of side effects, like dizziness. This is because sildenafil (Viagra), like Terazosin, relaxes your blood vessels to lower your blood pressure. Your provider may have you avoid using both Terazosin and sildenafil (Viagra) in order to prevent your blood pressure from dropping too low. Or, they might allow you to take both medications together, but at lower dosages or at separate times. Discuss with your provider if you have questions about this interaction.
Terazosin and tamsulosin are both alpha-1 blockers that are used for symptoms of BPH. Both medications are effective and can help ease urine flow. The American Urology Association doesn’t recommend one over the other. But your provider might choose either Terazosin or tamsulosin (Flomax) for you based on what other conditions you have. For example, tamsulosin (Flomax) is less likely to cause dizziness because it typically doesn’t lower blood pressure as much as Terazosin. So your provider might choose tamsulosin (Flomax) for you if you’re too dizzy from Terazosin. But if you have high blood pressure that’s not well-controlled, your provider might consider Terazosin over tamsulosin (Flomax) to help bring down your blood pressure.
