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doxazosin (Rx)Brand and Other Names:Cardura, Cardura XL, more...Doxadura

 
 
 

Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

tablet

  • 1mg
  • 2mg
  • 4mg
  • 8mg

tablet, extended release

  • 4mg
  • 8mg
more...

Hypertension

Immediate release: 1-16 mg PO once daily in AM or PM

Extended release: Not indicated for hypertension

Benign Prostatic Hyperplasia

Immediate release: 1-8 mg/day PO

Extended release: 4 mg/day PO initially at breakfast; may be increased to no more than 8 mg/day PO

Dosing Modifications

Hepatic impairment: Use with caution in mild-to-moderate hepatic dysfunction; do not use in severe impairment

Dosing Considerations

Give first dose and increase at bedtime to avoid syncope

Dosage Forms & Strengths

tablet

  • 1mg
  • 2mg
  • 4mg
  • 8mg
more...

Hypertension (Off-label)

Immediate release: 1-4 mg PO once daily in AM or PM

Hypertension

Avoid use for hypertension; high risk of orthostatic hypotension (Beers criteria); if used, lower initial dosages and gradual adjustments are recommended

Immediate release: 0.5-16 mg PO once daily in AM or PM

Extended release: Not indicated for hypertension

Benign Prostatic Hyperplasia

Immediate release: 1-8 mg/day PO

Extended release: 4 mg/day PO initially at breakfast; may be increased to no more than 8 mg/day PO

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Interactions

Interaction Checker

doxazosin and

No Results

     
     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            >10%

            Dizziness (5-19%)

            Fatigue (8-12%)

            Headache (6-10%)

            1-10%

            Vertigo (7%)

            Upper respiratory tract infection (URTI) (5%)

            Edema (3-4%)

            Rhinitis (3%)

            Dyspnea (1-3%)

            Abdominal pain (2%)

            Hypotension (1-2%)

            Nausea (1-2%)

            Orthostatic hypotension (dose related) (0.3-2%)

            Anxiety (1%)

            Palpitations (1%)

            Postmarketing experience

            Autonomic Nervous System: Priapism

            Cardiovascular System: Cerebrovascular accidents, dizziness postural, myocardial infarction

            Central and Peripheral Nervous System: Hypoesthesia, paresthesia

            Endocrine System: Gynecomastia

            Gastrointestinal System: Gastrointestinal obstruction, vomiting

            General Body System: Fatigue, hot flushes, malaise

            Heart Rate/Rhythm: Bradycardia, cardiac arrhythmias

            Hematopoietic: Leukopenia, purpura, thrombocytopenia

            Liver/Biliary System: Abnormal liver function tests, hepatitis, hepatitis cholestatic, jaundice

            Musculoskeletal System: Muscle cramps, muscle weakness

            Psychiatric: Agitation, anorexia, nervousness

            Respiratory System: Bronchospasm aggravated

            Skin Disorders: Alopecia, urticaria, skin rash, pruritus

            Special Senses: Blurred vision, intraoperative Floppy Iris Syndrome

            Urinary System: Hematuria, micturition disorder, micturition frequency, nocturia, polyuria

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            Warnings

            Contraindications

            Hypersensitivity to doxazosin or other quinazolines

            Cautions

            Use with caution in liver disease or recent cerebrovascular accident (CVA)

            Rule out prostate cancer before initiating therapy

            May cause first-dose syncope or sudden loss of consciousness

            Risk of orthostatic hypotension (dose dependent)

            Potential for hypotension, dry mouth, and urinary complications in elderly

            Priapism (painful penile erection, sustained for hours and unrelieved by sexual intercourse or masturbation) rarely reported (probably less frequently than once in every several thousand patients), with alpha-1 antagonists, including doxazosin; because condition can lead to permanent impotence if not promptly treated, patients must be advised about seriousness of condition

            Concomitant use of other antihypertensives (additive hypotensive effects)

            Extended-release form not indicated for hypertension

            Concomitant administration of immediate-release form with a phosphodiesterase-5 (PDE-5) inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension

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            Pregnancy & Lactation

            Pregnancy category: C

            Lactation: Unknown whether drug is excreted in milk; use with caution

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

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            Pharmacology

            Mechanism of Action

            Hypertension: Blocks postsynaptic alpha1 receptors; alpha blockade causes arterial, arteriolar, and venous dilation; decreases total peripheral resistance and blood pressure

            Benign prostatic hyperplasia (BPH): Blocks alpha1 receptors in prostatic stromal and bladder tissues; reduces sympathetic tone-induced urethral stricture responsible for BPH symptoms

            Absorption

            Bioavailability: Immediate release, 65%; extended release, 54-59%

            Onset (antihypertensive response): Peak, 4-8 hr

            Onset (BPH response): Initial, 2 wk; peak, 4-6 weeks

            Duration: 24 hr

            Peak plasma time: 2-3 hr

            Distribution

            Protein bound: 99%

            Vd: 1-3.4 L/kg

            Metabolism

            Metabolized extensively in liver

            Metabolites: 6- and 7-O-demethyl metabolites, 6'- and 7'-hydroxy metabolites, other minor metabolites (activity unknown)

            Elimination

            Half-life: Immediate release, 22 hr; extended release, 15-19 hr

            Dialyzable: HD, no

            Total body clearance: 83-140 mL/min

            Excretion: Feces (65%), urine (0.6-9%)

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            Images

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            Formulary

            FormularyPatient Discounts

            To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

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            • View the formulary and any restrictions for each plan.
            • Manage and view all your plans together – even plans in different states.
            • Compare formulary status to other drugs in the same class.
            • Access your plan list on any device – mobile or desktop.

            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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