Doxazosin

Class
Adrenergic receptor blockers
Subclass
Selective α1-blockers
Substance name
Doxazosin mesylate
Brand names
Cardura®
Common formulations
Tablet
See also
Doxazosin ER (Cardura XL®)
Dosage and administration
Adults patients
Treatment
BPH
•
Start at: 1 mg PO daily
•
Maintenance: 1-8 mg PO daily
•
Maximum: 8 mg per day
Titrate every 1-2 weeks based on response.
Hypertension
•
Start at: 1 mg PO daily
•
Maintenance: 1-16 mg PO daily
•
Maximum: 16 mg per day
Titrate based on response.
Ureteral stones • Off-label
•
2-4 mg PO daily for up to 4 weeks
Induction
Induction of preoperative α-blockade in patients with pheochromocytoma • Off-label
•
Start at: 2 mg PO daily 10-14 days before surgery
•
Maintenance: 32 mg PO daily achieving as the final dose
Other off-label uses
•
Treatment of chronic prostatitis/chronic pelvic pain syndrome
Indications for use
Labeled indications
Adults
•
Treatment of BPH
•
Treatment of hypertension
Off-label indications
Adults
•
Treatment of chronic prostatitis/chronic pelvic pain syndrome
•
Treatment of ureteral stones
•
Induction of preoperative α-blockade in patients with pheochromocytoma
Safety risks
Contraindications
Hypersensitivity to doxazosin or its components or other quinazolines
Concomitant use of other α-blockers
Warnings and precautions
Increased serum doxazosin levels
•
Use caution in patients taking potent CYP3A inhibitors. Monitor for hypotension.
Intraoperative floppy iris syndrome
•
Use caution in patients undergoing cataract surgery.
Mask symptoms of prostate cancer
•
Maintain a high level of suspicion, as prostate cancer can present with symptoms of BPH, and the two disorders frequently coexist. Exclude prostate cancer before initiating doxazosin.
Orthostatic hypotension, syncope
•
Use caution in all patients, especially those taking PDE5 inhibitors.
Priapism
•
Maintain a high level of suspicion, as an increased incidence has been reported in patients receiving doxazosin.
Specific populations
Renal impairment
eGFR 0-90 mL/min/1.73 m²
•
Use acceptable. No dose adjustment required.
Renal replacement therapy
Continuous renal replacement
•
Use acceptable. No dose adjustment required.
Intermittent hemodialysis
•
Use acceptable. No dose adjustment required.
Peritoneal dialysis
•
Use acceptable. No dose adjustment required.
Hepatic impairment
Child-Pugh A (mild)
•
Use with caution. Monitor for hypotension.
Child-Pugh B (moderate)
•
Use with caution. Monitor for hypotension.
Child-Pugh C (severe)
•
Do not use.
Pregnancy and breastfeeding
Pregnancy
All trimesters
•
Use only if benefits outweigh potential risks. Evidence of fetal harm in animals.
Breastfeeding
Use only if benefits outweigh potential risks.
•
Consider alternative agents that may be safer.
Unknown drug levels in breastfed infants.
Adverse reactions
Very common > 10%
•
Dizziness, fatigue, headache
Common 1-10%
•
Hypotension, orthostatic hypotension, peripheral edema, abdominal pain, anxiety, asthenia, dry mouth, dyspepsia, dyspnea, nausea, nosebleed, palpitations, polyuria, somnolence, vertigo, rhinitis
Uncommon < 1%
•
Arthralgia, chest pain, ↓ libido, diarrhea, hot flashes, muscle cramps, myalgia, syncope, stroke, tachycardia
Unknown frequency
•
Agitation, bradycardia, bronchospasm, ↓ WBC count, ↓ platelet count, drug-induced liver injury, gynecomastia, ↑ liver enzymes, intraoperative floppy iris syndrome, jaundice, myocardial infarction, purpura, blurred vision, blurred vision, hair loss, hematuria, hypoesthesia, loss of appetite, malaise, nocturia, paresthesia, priapism, pruritus, skin rash, urinary frequency, vomiting, urticaria
Interactions
Drug(s)
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