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doxazosin

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Brand names: Cardura

Alpha-1 Adrenergic Blocker Rx

Doxazosin is a medicine that can help lower high blood pressure and improve symptoms of an enlarged prostate in men.

Drug Pricing (NADAC)

Generic Price

$0.07/unit

Generic Available

Yes (10 manufacturers)

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

What it does

Doxazosin is used to treat high blood pressure (hypertension).

Common side effects

Dizziness, Feeling tired, Low blood pressure

Key warnings

Doxazosin can cause your blood pressure to drop suddenly when you stand up, leading to dizziness or fainting.

How It Works

Doxazosin belongs to a class of drugs called alpha-1 adrenergic 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 doxazosin once a day, either in the morning or evening. You can take it with or without food. For BPH, the starting dose is 1 mg daily, which may be increased every 1 to 2 weeks up to 8 mg daily. For high blood pressure, the starting dose is 1 mg daily, which may be increased as needed up to 16 mg daily.

Pregnancy & Breastfeeding

It is not known if doxazosin can harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant. Doxazosin does pass into breast milk in small amounts. Talk to your doctor about the best way to feed your baby if you are taking doxazosin.

Missed Dose

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

Storage

Store doxazosin tablets at room temperature, away from heat and moisture.

Side Effects (from patient reports)

Based on 11,686 FDA adverse event reports.

Shortness of breath
1,478
Feeling unsteady
1,295
Feeling very tired
1,276
Medication not working
1,251
Loose stools
1,237
Sudden kidney damage
1,135
Feeling sick to your stomach
1,133
Low blood pressure
988
Weakness
952
Pain in your head
941

FDA Adverse Event Report Analysis

Detailed analysis of 27,049 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2003–2025.

Total Reports

27,049

Death-Related Reports

2,269

Hospitalization Reports

11,467

Top Indication

Product Used For Unknown Indication

Gender Distribution

Female 8,688 (35%)
Male 16,206 (65%)

Age Distribution

0–17 206
18–44 1,048
45–64 5,427
65–74 6,253
75+ 7,693

Most Reported Adverse Reactions (FAERS)

# Reaction Reports
1 DYSPNOEA 1,479
2 DIZZINESS 1,295
3 FATIGUE 1,276
4 DRUG INEFFECTIVE 1,250
5 DIARRHOEA 1,237
6 ACUTE KIDNEY INJURY 1,135
7 NAUSEA 1,131
8 HYPOTENSION 988
9 ASTHENIA 950
10 HEADACHE 941
11 HYPERTENSION 853
12 DRUG INTERACTION 851
13 VOMITING 835
14 OFF LABEL USE 781
15 RENAL FAILURE 773

Reactions in Death Reports

DEATH 677
RENAL FAILURE 165
DYSPNOEA 163
PNEUMONIA 140
ACUTE KIDNEY INJURY 136
CARDIAC ARREST 100
ASTHENIA 98
CHRONIC KIDNEY DISEASE 97
MYOCARDIAL INFARCTION 95
SEPSIS 93

Reactions in Hospitalization Reports

DYSPNOEA 825
ACUTE KIDNEY INJURY 806
HYPOTENSION 613
FALL 522
DIARRHOEA 514
PNEUMONIA 505
VOMITING 501
DIZZINESS 473
ANAEMIA 471
DRUG INTERACTION 451

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

Serious Warnings

Doxazosin can cause your blood pressure to drop suddenly when you stand up, leading to dizziness or fainting. This is more likely when you first start taking it or when the dose is increased. If you are having cataract surgery, tell your doctor you are taking this medicine. Doxazosin has been linked to priapism (a painful erection lasting for hours). If this happens, seek medical attention right away.

Known Drug Interactions

Postural hypotension has been reported in patients taking both beta-blockers and terazosin or doxazosin.

Mechanism: Both drugs lower blood pressure, which can cause a sudden drop in pressure when you stand up. This can make you feel dizzy or faint.

What to do: Stand up slowly from a sitting or lying position to avoid falling. Your doctor may need to adjust your medication doses.

Clinical pharmacology studies have been conducted with coadministration of tadalafil with doxazosin, tamsulosin or alfuzosin.

Mechanism: Both of these medications can lower your blood pressure, and taking them together might cause your blood pressure to drop too low.

What to do: Your doctor should monitor your blood pressure closely and may need to adjust your doses.

Common Questions

Can I drink alcohol while taking doxazosin?
Alcohol can lower your blood pressure and may increase the dizziness caused by doxazosin. Talk to your doctor before drinking alcohol.
How long does it take for doxazosin to start working?
You may notice an improvement in BPH symptoms within a few weeks. It may take several weeks for your blood pressure to be controlled.
Can I stop taking doxazosin suddenly?
Do not stop taking doxazosin without talking to your doctor. Stopping suddenly can cause your blood pressure to increase.
Does doxazosin affect my ability to drive or operate machinery?
Doxazosin can cause dizziness or lightheadedness, especially when you first start taking it. Be careful driving or operating machinery until you know how doxazosin affects you.
Will doxazosin cure my enlarged prostate?
Doxazosin can help relieve the symptoms of an enlarged prostate, but it does not cure the condition.
Can women take doxazosin?
Doxazosin is primarily used to treat conditions in men, such as enlarged prostate. Talk to your doctor about other options.
What should I do if I feel dizzy after taking doxazosin?
Lie down until the dizziness passes. Avoid standing up quickly.
Can I take doxazosin with other medications?
Tell your doctor about all the medications you are taking, including over-the-counter drugs and supplements, before starting doxazosin.
Will doxazosin affect my sexual function?
Doxazosin can cause sexual side effects, such as difficulty with ejaculation. Talk to your doctor if you experience these side effects.
How often should I see my doctor while taking doxazosin?
Follow your doctor's instructions for regular check-ups while taking doxazosin.
What are the common side effects of doxazosin?
The most commonly reported side effects of doxazosin include Dizziness, Feeling tired, Low blood pressure, Swelling, Runny nose. Based on 11,686 FDA adverse event reports. Always consult your healthcare provider about potential side effects.
Does doxazosin interact with other medications?
Yes, doxazosin has 2 known drug interactions. Notable interactions include propranolol, tadalafil. Always inform your doctor about all medications you are taking.
What drug class is doxazosin?
doxazosin belongs to the Alpha-1 Adrenergic Blocker drug class. It requires a prescription (Rx). Doxazosin is used to treat high blood pressure (hypertension).
Is doxazosin safe during pregnancy?
It is not known if doxazosin can harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant. Always consult your healthcare provider before using any medication during pregnancy or breastfeeding.
Has doxazosin been recalled?
There is 1 recall associated with doxazosin products. cGMP Deviations for the manufacturing Firm (Accord Healthcare) after their inspection. Check the recalls section below for full details and affected products.

Active Recalls

Class II March 23, 2023

cGMP Deviations for the manufacturing Firm (Accord Healthcare) after their inspection.

Preferred Pharmaceuticals, Inc.

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What the FDA Data Shows for doxazosin

The FDA label for doxazosin (sold under brand names such as Cardura) classifies it as a prescription-only medication in the Alpha-1 Adrenergic Blocker class. Doxazosin is used to treat high blood pressure (hypertension). Official labeling lists 6 commonly reported side effects, including Dizziness, Feeling tired, Low blood pressure.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 11,686 voluntary reports. The database also lists 2 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 $0.07.

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 (currently 1 recall record on file), 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: March 31, 2025

All federal data sources used on this page