Cardura (doxazosin mesylate) is an alpha-1 adrenergic blocker medication primarily prescribed for the management of hypertension (high blood pressure) and the treatment of symptomatic benign prostatic hyperplasia (BPH). As a selective antagonist of alpha-1 adrenergic receptors located in vascular smooth muscle and the prostate, Cardura works by causing vasodilation and relaxation of smooth muscles in the bladder neck and prostate. This dual mechanism of action makes it a valuable therapeutic option for patients presenting with either condition or both concurrently. Clinical evidence supports its efficacy in reducing blood pressure and improving urinary flow rates while demonstrating a generally favorable tolerability profile when administered under appropriate medical supervision.

Features

• Active ingredient: Doxazosin mesylate
• Available in 1 mg, 2 mg, 4 mg, and 8 mg oral tablet formulations
• Selective alpha-1 adrenergic receptor blockade
• Extended-release and immediate-release formulations (Cardura XL® and standard)
• Once-daily dosing convenience for most patients
• FDA-approved for hypertension and symptomatic BPH

Benefits

• Effectively lowers both systolic and diastolic blood pressure, reducing cardiovascular risk
• Improves urinary flow and reduces symptoms of BPH, including hesitancy, weak stream, and nocturia
• Single-agent therapy with potential dual benefits for patients with concomitant hypertension and BPH
• Generally well-tolerated with a established safety profile spanning decades of clinical use
• Does not adversely affect blood lipid profiles or glucose metabolism
• May be used concomitantly with other antihypertensive agents for enhanced blood pressure control

Common use

Cardura is commonly prescribed for the management of essential hypertension, either as monotherapy or in combination with other antihypertensive medications such as diuretics, beta-blockers, or ACE inhibitors. In urological practice, it is indicated for the treatment of symptomatic benign prostatic hyperplasia to improve urinary flow and reduce obstructive and irritative symptoms. Some off-label uses include the management of Raynaud’s phenomenon and the treatment of ureteral stones due to its smooth muscle relaxant properties. The medication may be particularly beneficial for male patients who present with both hypertension and BPH, allowing for simplified treatment regimens.

Dosage and direction

For hypertension: Initial dose is 1 mg once daily, which may be increased to 2 mg, 4 mg, and up to 8 mg or 16 mg daily based on blood pressure response. Dosage adjustments should typically occur at 2-week intervals.

For BPH: Initial dose is 1 mg once daily, with titration to 2 mg, 4 mg, and 8 mg daily as needed based on symptomatic response and tolerability. The maximum recommended dose is 8 mg daily.

Cardura should be taken at the same time each day, with or without food. The extended-release formulation (Cardura XL) should be swallowed whole and not crushed or chewed. Initial dosing should occur at bedtime to minimize potential orthostatic effects, though subsequent doses may be taken in the morning if well-tolerated.

Precautions

Patients should be cautioned about the potential for orthostatic hypotension, particularly during initial titration or when increasing the dose. This risk may be increased with concomitant alcohol consumption, prolonged standing, exercise, and hot weather. Caution should be exercised when driving or operating machinery until the individual response is established. Regular monitoring of blood pressure is recommended, especially during dose adjustments. Patients with impaired hepatic function may require dose adjustment or alternative therapy due to reduced metabolism. Cataract surgery patients should inform their surgeon about doxazosin use due to the potential for intraoperative floppy iris syndrome (IFIS).

Contraindications

Cardura is contraindicated in patients with known hypersensitivity to doxazosin, other quinazolines (prazosin, terazosin), or any component of the formulation. It should not be used in patients with a history of orthostatic hypotension or in those with severe hepatic impairment. Concomitant use with other alpha-adrenergic blocking agents is contraindicated due to the potential for additive hypotensive effects. The medication is not indicated for use in pediatric patients or for the treatment of pulmonary hypertension.

Possible side effect

Common side effects (≥2%) include dizziness (15.6%), fatigue (8.1%), hypotension (3.9%), somnolence (3.5%), nausea (2.9%), and edema (2.7%). Orthostatic hypotension occurs in approximately 0.3-1% of patients. Less frequent adverse reactions include headache, rhinitis, palpitations, pain, dyspnea, and abdominal pain. Priapism, though rare, constitutes a medical emergency requiring immediate attention. Other infrequently reported effects include visual disturbances, tinnitus, and skin rash. Most side effects are dose-dependent and often diminish with continued therapy.

Drug interaction

Cardura may potentiate the hypotensive effects of other antihypertensive agents, diuretics, phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil), and nitrates. Concomitant use with other alpha-adrenergic blockers should be avoided. CYP3A4 inhibitors such as ketoconazole, itraconazole, and ritonavir may increase doxazosin concentrations, while inducers like rifampin may decrease its efficacy. Nonsteroidal anti-inflammatory drugs may attenuate the antihypertensive effect. Caution is advised when combining with medications that prolong the QT interval. The medication may enhance the effects of alcohol on cognitive and motor performance.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is nearly time for the next scheduled dose. In that case, the missed dose should be skipped, and the regular dosing schedule resumed. Patients should not double the dose to make up for a missed one. If multiple doses are missed, consultation with a healthcare provider is recommended before restarting therapy, as dose retitration may be necessary to minimize orthostatic effects.

Overdose

Symptoms of overdose may include pronounced hypotension, dizziness, lightheadedness, and syncope. Supportive care should include placing the patient in a supine position and administering intravenous fluids if necessary. Vasopressors may be required for severe hypotension, with norepinephrine being preferred over epinephrine due to more selective alpha-adrenergic activity. Gastric lavage may be considered if ingestion was recent. Hemodialysis is not effective due to high protein binding. Patients should receive continuous cardiovascular monitoring until stable.

Storage

Store at controlled room temperature (20-25°C or 68-77°F) in the original container with the lid tightly closed. Protect from light and excessive moisture. Keep out of reach of children and pets. Do not use after the expiration date printed on the packaging. Do not transfer tablets to other containers, as this may affect stability. Discard any medication that appears discolored or shows signs of deterioration.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Cardura is a prescription medication that should be used only under the supervision of a qualified healthcare professional. Individual response to therapy may vary, and treatment decisions should be based on a thorough evaluation by a physician. Patients should not initiate, adjust, or discontinue medication without consulting their healthcare provider. The complete prescribing information should be consulted before administration.

Reviews

Clinical studies demonstrate that Cardura effectively reduces blood pressure by 10-15 mmHg systolic and 5-10 mmHg diastolic in hypertensive patients. In BPH trials, it shows significant improvement in symptom scores (30-40% reduction) and peak urinary flow rates (2-3 mL/sec increase). Patient satisfaction surveys indicate improved quality of life measures related to both cardiovascular and urinary symptoms. Long-term follow-up studies confirm maintained efficacy with continued therapy. Most adverse effects are reported as mild to moderate and often diminish with continued treatment. The medication receives generally positive evaluations from prescribing physicians for its dual-action benefits and flexible dosing options.