Doxazosin
Doxazosin is an alpha-1 blocker medication used to treat high blood pressure (hypertension) and benign prostatic hyperplasia (BPH), a condition where the prostate gland is enlarged in men. It works by relaxing blood vessels to allow easier blood flow and by relaxing smooth muscle in the prostate and bladder neck to improve urinary symptoms.
Doxazosin is an alpha blocker that treats high blood pressure and enlarged prostate symptoms by relaxing blood vessels and smooth muscle.
Key facts at a glance
- ATC
- C02CA04
- RxNorm
- 49276
- Generic
- Doxazosin
- Class
- atc-c02
- Brands
- Cardura
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 1mg once daily
- Maximum
- consult physician
- Frequency
- once daily (usually at bedtime)
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 1-16mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 1-8mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
9 groupspregnancy
first trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks
regular fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks
regular fetal monitoring and uterine blood flow assessment
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
third trimesteravoid if possible
avoid use near term due to risk of hypotension in newborn
monitor neonatal blood pressure after delivery
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedinguse with caution
discontinue breastfeeding or discontinue drug; excreted in breast milk in small amounts
monitor infant for hypotension and excessive drowsiness
Use with caution and monitor for adverse effects.
geriatric
elderlystart at low dose and titrate slowly
increased sensitivity to hypotensive effects; higher risk of orthostatic hypotension
monitor blood pressure regularly including orthostatic measurements
Use with caution and monitor for adverse effects.
pediatric_age
children adolescentsnot established
safety and efficacy not established in pediatric patients
limited data available
renal_impairment
moderate to severeadjust dose based on renal function
use with caution; no significant change in pharmacokinetics but monitor response
monitor renal function and blood pressure regularly
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderatereduce starting dose
use with caution; extensively metabolized in liver
monitor liver function tests and blood pressure
Use with caution and monitor for adverse effects.
hepatic_impairment
severeuse lowest possible dose
use with extreme caution; not recommended in severe hepatic impairment
frequent monitoring of liver function and blood pressure
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA approval year
Original FDA approval date for doxazosin
Drug class
Pharmacological classification according to WHO ATC system
Primary indications
FDA-approved therapeutic indications
Mechanism of action
Primary pharmacodynamic mechanism
Doxazosin is FDA-approved for treating hypertension and benign prostatic hyperplasia (BPH). For BPH, it helps relieve urinary symptoms such as difficulty starting urination, weak stream, and frequent urination.
As an alpha-1 adrenergic blocker, doxazosin inhibits alpha-1 receptors on smooth muscle in blood vessels, causing vasodilation and reduced peripheral resistance to lower blood pressure. In the prostate and bladder neck, blocking these receptors relaxes smooth muscle, reducing obstruction and improving urine flow.
Doxazosin may cause orthostatic hypotension, especially with the first dose ('first-dose effect'), so treatment often starts with a low dose taken at bedtime. Common side effects include dizziness, headache, fatigue, and nasal congestion. It is not a cure for BPH but manages symptoms and does not treat prostate cancer. Patients should rise slowly from sitting or lying positions and avoid operating machinery until they know how the medication affects them.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 24, 2026. · Read our editorial policy