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Cardura Side Effects

Generic name: doxazosin

Medically reviewed by Last updated on Mar 29, 2023.

Note: This document contains side effect information about doxazosin. Some dosage forms listed on this page may not apply to the brand name Cardura.

Applies to doxazosin: oral tablet, oral tablet extended release.

Serious side effects of Cardura

Along with its needed effects, doxazosin (the active ingredient contained in Cardura) 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 while taking doxazosin:

More common

  • Dizziness or lightheadedness

Less common

  • Blurred vision
  • confusion
  • dizziness, faintness, or lightheadedness when getting up from a lying or sitting position
  • fainting (sudden)
  • fast and pounding heartbeat
  • irregular heartbeat
  • shortness of breath
  • sweating
  • swelling of feet or lower legs


  • Painful or prolonged erection of the penis (called priapism), although extremely rare, must have immediate medical attention. If painful or prolonged erection occurs, call your doctor or go to an emergency room as soon as possible

Incidence not known

  • Abdominal or stomach pain
  • area rash
  • black, tarry stools
  • bleeding gums
  • blood in urine or stools
  • chest pain or discomfort
  • chills
  • clay-colored stools
  • cough
  • dark urine
  • diarrhea
  • difficulty breathing
  • difficult, burning, or painful urination
  • fever
  • general tiredness and weakness
  • headache, sudden and severe
  • inability to speak
  • itching
  • lab results that show problems with liver
  • light-colored stools
  • loss of appetite
  • noisy breathing
  • pain or discomfort in arms, jaw, back or neck
  • pinpoint red or purple spots on skin
  • rash
  • seizures
  • slow or irregular heartbeat
  • slurred speech
  • sore throat
  • sores, ulcers, or white spots on lips or in mouth
  • swollen glands
  • temporary blindness
  • tightness in chest
  • unpleasant breath odor
  • unusual bleeding or bruising
  • upper right abdominal pain
  • vomiting
  • vomiting of blood
  • weakness in arm and/or leg on one side of the body, sudden and severe
  • wheezing
  • yellow eyes and skin

Other side effects of Cardura

Some side effects of doxazosin 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
  • lack or loss of strength
  • unusual tiredness or weakness

Less common

  • Acid or sour stomach
  • back pain
  • belching
  • bladder pain
  • cloudy urine
  • difficulty in moving
  • frequent urge to urinate
  • heartburn
  • indigestion
  • joint pain
  • lower back or side pain
  • muscle aching, cramping, or weakness
  • muscle pains or stiffness
  • nausea
  • nervousness, restlessness, unusual irritability
  • runny nose
  • sleepiness or drowsiness
  • sneezing
  • sore throat
  • stomach discomfort, upset or pain
  • swollen joints

Incidence not known

  • Anxiety
  • burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feeling
  • change in frequency or urination
  • dry mouth
  • feeling of warmth
  • frequent urination
  • general feeling of discomfort or illness
  • hair loss
  • hives or welts
  • hyperventilation
  • increased urge to urinate during the night
  • increased volume of pale dilute urine
  • loss of appetite
  • painful urination
  • redness of skin
  • redness of the face, neck, arms and occasionally upper chest
  • shaking
  • swelling of the breasts or breast soreness in both females and males
  • thinning of hair
  • trouble in holding or releasing urine
  • trouble sleeping
  • waking to urinate at night
  • weight loss

For Healthcare Professionals

Applies to doxazosin: oral tablet, oral tablet extended release.


The most common adverse reaction was dizziness.[Ref]

Nervous system

Very common (10% or more): Dizziness (up to 19%)

Common (1% to 10%): Somnolence, headache, vertigo

Uncommon (0.1% to 1%): Cerebrovascular accident, hypoesthesia, syncope, tremor, tinnitus

Very rare (less than 0.01%): Dizziness postural, paresthesia

Frequency not reported: Taste disturbance[Ref]


Very common (10% or more): Fatigue/malaise (12%)

Common (1% to 10%): Asthenia, chest pain, influenza-like symptoms

Uncommon (0.1% to 1%): Pain, facial edema[Ref]


Common (1% to 10%): Dyspnea, rhinitis, respiratory tract infection, bronchitis, cough

Uncommon (0.1% to 1%): Epistaxis

Very rare (less than 0.01%): Bronchospasm

Postmarketing reports: Bronchospasm aggravated[Ref]


Common (1% to 10%): Dry mouth, abdominal pain, dyspepsia, nausea

Uncommon (0.1% to 1%): Constipation, flatulence, vomiting, gastroenteritis, diarrhea

Frequency not reported: Gastrointestinal obstruction[Ref]


Common (1% to 10%): Polyuria, urinary tract infection, cystitis, urinary incontinence

Uncommon (0.1% to 1%): Dysuria, micturition frequency, hematuria, impotence

Very rare (less than 0.01%): Micturition disorder, nocturia, priapism

Frequency not reported: Retrograde ejaculation[Ref]


Common (1% to 10%): Hypotension, postural hypotension, palpitation, tachycardia

Uncommon (0.1% to 1%): Angina pectoris, myocardial infarction

Very rare (less than 0.01%): Bradycardia, cardiac arrhythmias, hot flushes[Ref]


Common (1% to 10%): Edema, peripheral edema

Uncommon (0.1% to 1%): Gout, appetite increased, anorexia, weight increased[Ref]


Common (1% to 10%): Myalgia, back pain

Uncommon (0.1% to 1%): Arthralgia

Rare (less than 0.1%): Muscle cramps, muscle weakness[Ref]


Common (1% to 10%): Pruritus

Uncommon (0.1% to 1%): Skin rash

Very rare (less than 0.01%): Urticaria, purpura, alopecia[Ref]


Uncommon (0.1% to 1%): Agitation, depression, anxiety, insomnia, nervousness

Frequency not reported: Libido decreased[Ref]


Uncommon (0.1% to 1%): Abnormal liver function tests

Very rare (less than 0.01%): Cholestasis, hepatitis, jaundice

Postmarketing reports: Hepatitis cholestatic[Ref]


Uncommon (0.1% to 1%): Allergic drug reaction

Postmarketing reports: Allergic reaction[Ref]


Very rare (less than 0.01%): Leukopenia, thrombocytopenia

Frequency not reported: White blood cell counts decreased, neutrophil count decreased[Ref]


Very rare (less than 0.01%): Blurred vision

Frequency not reported: Intraoperative Floppy Iris Syndrome (IFIS)[Ref]


Very rare (less than 0.01%): Gynecomastia[Ref]


Very rare (less than 0.01%): Diuresis increased[Ref]


1. Product Information. Cardura (doxazosin). Pfizer U.S. Pharmaceuticals. 2001.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.