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terazosin

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Brand names: Hytrin

Alpha-1 Blocker Rx

Terazosin is a medicine that can help men with enlarged prostate and also treat high blood pressure. It works by relaxing certain muscles in your body.

Drug Pricing (NADAC)

Generic Price

$0.15/unit

Generic Available

Yes (5 manufacturers)

Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →

What it does

Terazosin is used to treat enlarged prostate in men.

Common side effects

Feeling weak or tired, Dizziness, Stuffy nose

Key warnings

Be careful when you first start taking terazosin, as it can cause your blood pressure to drop too low.

How It Works

Terazosin belongs to a class of drugs called alpha-1 blockers. It works by relaxing the muscles in the prostate and bladder neck, making it easier to urinate. It also relaxes blood vessels, which helps to lower blood pressure.

How to Take It

Take terazosin capsules as directed by your doctor. For enlarged prostate, the starting dose is 1 mg at bedtime. Your doctor may increase the dose slowly to 2 mg, 5 mg, or 10 mg once a day. For high blood pressure, the usual dose is 1 mg to 5 mg once a day, but some people may need up to 20 mg.

Pregnancy & Breastfeeding

It is not known if terazosin can harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if terazosin passes into breast milk, so talk to your doctor if you are breastfeeding.

Missed Dose

If you miss a dose of terazosin, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.

Storage

Store terazosin capsules at room temperature (68 to 77°F) in a tight, light-resistant container, away from light and moisture.

Side Effects (from patient reports)

Based on 3,730 FDA adverse event reports.

The medicine is not working
474
Tiredness
466
Diarrhea
395
Feeling dizzy
385
Difficulty breathing
383
Weakness
351
Sudden kidney damage
331
Death
325
Long-term kidney disease
319
Kidney failure
301

FDA Adverse Event Report Analysis

Detailed analysis of 7,436 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2002–2025.

Total Reports

7,436

Death-Related Reports

836

Hospitalization Reports

2,657

Top Indication

Product Used For Unknown Indication

Gender Distribution

Female 1,047 (15%)
Male 5,875 (85%)

Age Distribution

0–17 12
18–44 162
45–64 1,186
65–74 1,637
75+ 2,102

Most Reported Adverse Reactions (FAERS)

# Reaction Reports
1 DRUG INEFFECTIVE 474
2 FATIGUE 466
3 DIARRHOEA 395
4 DIZZINESS 385
5 DYSPNOEA 383
6 ASTHENIA 351
7 ACUTE KIDNEY INJURY 331
8 DEATH 325
9 CHRONIC KIDNEY DISEASE 319
10 RENAL FAILURE 301
11 OFF LABEL USE 297
12 FALL 283
13 NAUSEA 282
14 PAIN 267
15 PNEUMONIA 253

Reactions in Death Reports

DEATH 325
ACUTE KIDNEY INJURY 61
PNEUMONIA 61
RENAL FAILURE 57
CHRONIC KIDNEY DISEASE 55
FALL 46
CARDIAC ARREST 45
DYSPNOEA 45
ASTHENIA 38
END STAGE RENAL DISEASE 38

Reactions in Hospitalization Reports

FALL 198
PNEUMONIA 192
DYSPNOEA 187
ACUTE KIDNEY INJURY 179
ASTHENIA 174
HYPOTENSION 157
GASTROINTESTINAL HAEMORRHAGE 149
DIZZINESS 148
FATIGUE 148
RENAL FAILURE 140

Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation

Serious Warnings

Be careful when you first start taking terazosin, as it can cause your blood pressure to drop too low. This can lead to dizziness or fainting. Take your first dose at bedtime and be careful when standing up.

Known Drug Interactions

Terazosin has been used concomitantly in at least 50 patients on the following drugs or drug classes: analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); antigout (e.g., allopurinol); antihistamines (e.g., chlorpheniramine); cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); corticosteroids; gastrointestinal...

Mechanism: Both drugs are used to lower blood pressure. Taking them at the same time can cause an additive effect, making your blood pressure drop lower than usual.

What to do: Your doctor may need to monitor your blood pressure more often. Be careful when standing up to avoid dizziness.

Terazosin has been used concomitantly in at least 50 patients on the following drugs or drug classes: analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); antigout (e.g., allopurinol); antihistamines (e.g., chlorpheniramine); cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); corticosteroids; gastrointestinal...

Mechanism: Ibuprofen belongs to a class of drugs that can cause the body to retain fluid. This may make blood pressure medications like terazosin less effective.

What to do: Let your doctor know if you take ibuprofen regularly. They may want to check your blood pressure to ensure the medicine is still working well.

Terazosin has been used concomitantly in at least 50 patients on the following drugs or drug classes: analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); antigout (e.g., allopurinol); antihistamines (e.g., chlorpheniramine); cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); corticosteroids; gastrointestinal...

Mechanism: These medications have been used together in clinical trials without any reported problems. There is no known negative interaction between them.

What to do: You can continue taking both medications as prescribed. No special monitoring is usually necessary for this combination.

minor aspirin

Terazosin has been used concomitantly in at least 50 patients on the following drugs or drug classes: analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); antigout (e.g., allopurinol); antihistamines (e.g., chlorpheniramine); cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); corticosteroids; gastrointestinal...

Mechanism: These drugs have been used together in many patients without any harmful effects being reported. They do not typically interfere with each other.

What to do: No special changes are typically needed when taking these together. Follow your doctor's instructions for both medicines.

Terazosin has been used concomitantly in at least 50 patients on the following drugs or drug classes: analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); antigout (e.g., allopurinol); antihistamines (e.g., chlorpheniramine); cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); corticosteroids; gastrointestinal...

Mechanism: Both of these medications work to lower blood pressure. Using them together can cause your blood pressure to drop more than if you took only one.

What to do: Your doctor might need to adjust your dose. Watch for signs of dizziness or lightheadedness, especially when you first start taking them together.

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Common Questions

Can I take terazosin with other blood pressure medicines?
Yes, terazosin can be used with other blood pressure medicines, but your doctor may need to adjust the doses.
How long does it take for terazosin to start working?
You may notice an improvement in your symptoms within a few weeks of starting terazosin.
Can terazosin cause dizziness?
Yes, dizziness is a common side effect of terazosin, especially when you first start taking it.
Can I drink alcohol while taking terazosin?
Talk to your doctor about drinking alcohol while taking terazosin, as it can increase the risk of dizziness.
What should I do if I feel dizzy after taking terazosin?
Lie down until the dizziness passes. Be careful when standing up.
Can terazosin affect my sex life?
Yes, terazosin can cause impotence (trouble getting an erection) in some men.
Is it safe to drive while taking terazosin?
Be careful driving or operating machinery until you know how terazosin affects you, as it can cause dizziness.
What are the different strengths of terazosin capsules?
Terazosin capsules come in 1 mg, 2 mg, 5 mg, and 10 mg strengths.
How should I dispose of unused terazosin capsules?
Talk to your pharmacist about how to properly dispose of unused terazosin capsules.
Can I stop taking terazosin suddenly?
Do not stop taking terazosin suddenly without talking to your doctor, as this can cause your blood pressure to increase.
What are the common side effects of terazosin?
The most commonly reported side effects of terazosin include Feeling weak or tired, Dizziness, Stuffy nose, Headache. Based on 3,730 FDA adverse event reports. Always consult your healthcare provider about potential side effects.
Does terazosin interact with other medications?
Yes, terazosin has 15 known drug interactions. Notable interactions include hydrochlorothiazide, ibuprofen, allopurinol. Always inform your doctor about all medications you are taking.
What drug class is terazosin?
terazosin belongs to the Alpha-1 Blocker drug class. It requires a prescription (Rx). Terazosin is used to treat enlarged prostate in men.
Is terazosin safe during pregnancy?
It is not known if terazosin can harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. Always consult your healthcare provider before using any medication during pregnancy or breastfeeding.

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What the FDA Data Shows for terazosin

The FDA label for terazosin (sold under brand names such as Hytrin) classifies it as a prescription-only medication in the Alpha-1 Blocker class. Terazosin is used to treat enlarged prostate in men. Official labeling lists 4 commonly reported side effects, including Feeling weak or tired, Dizziness, Stuffy nose.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 3,730 voluntary reports. The database also lists 15 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS shows a generic unit cost of $0.15.

Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.

Last updated: July 20, 2023

All federal data sources used on this page