Cardura (doxazosin mesylate) is an alpha-1 adrenergic blocker medication prescribed for the management of hypertension (high blood pressure) and the treatment of symptomatic benign prostatic hyperplasia (BPH). It functions by relaxing blood vessels and muscles in the prostate and bladder neck, facilitating smoother blood flow and improved urinary function. This dual-action mechanism makes it a versatile option in a clinician’s therapeutic arsenal for addressing these common conditions.

Features

• Active pharmaceutical ingredient: Doxazosin mesylate.
• Available in oral tablet formulations (1 mg, 2 mg, 4 mg, 8 mg).
• Class: Selective antagonist of postsynaptic alpha-1 adrenergic receptors.
• Standard release formulation; not available in an extended-release form for this brand.
• Proven efficacy in clinical trials for reducing both systolic and diastolic blood pressure.
• Demonstrated improvement in urine flow rates and reduction in BPH symptom scores.

Benefits

• Provides effective control of high blood pressure, reducing the long-term risk of stroke, heart attack, and kidney damage.
• Significantly alleviates lower urinary tract symptoms associated with BPH, such as weak stream, hesitancy, and nocturia, improving quality of life.
• Offers a single-agent therapeutic option for male patients presenting with both hypertension and symptomatic BPH.
• Generally well-tolerated with a predictable side effect profile when dosed appropriately.
• Rapid onset of action for symptomatic relief in BPH, often within one to two weeks.
• Does not adversely affect blood lipid levels or glucose metabolism.

Common use

Cardura is primarily indicated for two conditions. First, it is used in the treatment of hypertension, either as monotherapy or in combination with other antihypertensive agents such as diuretics or beta-blockers. Second, it is indicated for the treatment of the signs and symptoms of benign prostatic hyperplasia. It is important to note that while it improves urine flow and symptoms, it does not reduce the size of the prostate gland itself. Treatment is typically long-term, requiring ongoing medical supervision to ensure efficacy and monitor for tolerability.

Dosage and direction

Dosage must be individualized based on the patient’s therapeutic response and tolerability.

For Hypertension:

• The initial dosage is 1 mg administered once daily.
• The dosage may be increased gradually, typically after 1-2 weeks, to 2 mg once daily.
• Further increments to 4 mg, 8 mg, and a maximum of 16 mg once daily may be necessary to achieve the desired blood pressure response.
• The dose should be taken at the same time each day, with or without food.

For Benign Prostatic Hyperplasia:

• The initial dosage is 1 mg administered once daily.
• Depending on the patient’s symptomatic response and tolerability, the dose may be increased to 2 mg and then to 4 mg and 8 mg once daily.
• The recommended titration interval is 1-2 weeks.
• The maximum recommended dose for BPH is 8 mg once daily.

Important Administration Note: Due to the risk of first-dose hypotension (a sudden drop in blood pressure), the initial dose should be taken at bedtime. This practice minimizes the risk of syncope (fainting) or dizziness. Patients should not drive or operate machinery for 12-24 hours after the first dose or any subsequent dose increase.

Precautions

• Orthostatic Hypotension: Patients should be cautioned about the potential for dizziness, lightheadedness, or fainting, particularly when rising from a sitting or lying position. This is most common during initiation and dose titration.
• Priapism: Although rare, prolonged and painful erections (priapism) have been reported. This condition requires immediate medical attention to prevent permanent damage.
• Intraoperative Floppy Iris Syndrome (IFIS): This alpha-1 blocker class effect has been observed during cataract surgery. Surgeons should be informed of the patient’s use of Cardura prior to any cataract procedure.
• Use in Specific Populations: Use with caution in patients with severe hepatic impairment. Safety and efficacy in children have not been established.
• Pregnancy and Lactation: Cardura is not recommended for use in women. It is not indicated for use in pregnant women or nursing mothers.

Contraindications

Cardura is contraindicated in patients with a known hypersensitivity to doxazosin, other quinazolines (e.g., prazosin, terazosin), or any component of the formulation.

Possible side effect

Like all medications, Cardura can cause side effects, although not everybody gets them. Most are dose-dependent and often diminish with continued therapy.

Very Common (≥1/10):

• Dizziness
• Fatigue

Common (≥1/100 to <1/10):

• Postural dizziness
• Postural hypotension
• Headache
• Somnolence (drowsiness)
• Nausea
• Edema (swelling)
• Rhinitis (nasal congestion)

Uncommon (≥1/1,000 to <1/100):

• Palpitations
• Pain (abdominal, back)
• Dry mouth
• Dyspnea (shortness of breath)
• Blurred vision
• Urinary incontinence
• Impotence

Rare (<1/1,000):

• Priapism
• Syncope (fainting)
• Hepatitis
• Leukopenia
• Thrombocytopenia

Drug interaction

Concomitant use of Cardura with other medications that lower blood pressure, including other antihypertensives and phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil, vardenafil), may potentiate the hypotensive effect and increase the risk of orthostasis and syncope. Caution is advised when administering Cardura with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir), as they may increase doxazosin plasma concentrations. Inform your physician of all prescription, over-the-counter, and herbal products you are taking.

Missed dose

If a dose is missed, it should be taken as soon as remembered on that same day. If it is not remembered until the next day, the missed dose should be skipped, and the regular dosing schedule resumed. Do not take a double dose to make up for a forgotten one.

Overdose

In the event of an overdose, the primary expected manifestation is exaggerated pharmacological effects, leading to profound hypotension (extremely low blood pressure), sometimes accompanied by shock. Circulatory support is the cornerstone of management. The patient should be placed in a supine position with their legs elevated. This position helps restore blood pressure and ensure brain perfusion. Vital functions should be monitored and supported as necessary. Gastric lavage or the administration of activated charcoal may be considered if ingestion was recent. Vasopressors may be required to support blood pressure, with care taken to not precipitate a paradoxical response. Due to high protein binding, doxazosin is not dialyzable.

Storage

Store Cardura tablets at room temperature (15°-30°C or 59°-86°F). Protect from light and moisture. Keep in the original container and out of reach of children and pets. Do not use after the expiration date printed on the packaging.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any new treatment. Never disregard professional medical advice or delay in seeking it because of something you have read here.

Reviews

“Cardura has been a cornerstone in my practice for managing patients with concomitant hypertension and BPH. The titration process is key to managing the initial side effects, but for persistent patients, the dual benefit is undeniable. It effectively improves urinary flow and controls BP without the metabolic concerns of some other classes.” – Urologist, 15 years of experience.

“In my cardiology practice, I find Cardura to be a useful add-on agent for resistant hypertension. The first-dose hypotension is a real consideration, so I always initiate at bedtime. Once titrated, most patients tolerate it well, and it provides a reliable antihypertensive effect.” – Cardiologist, 10 years of experience.

“After the first week of dizziness, my symptoms have improved dramatically. I can sleep through the night now without getting up to use the bathroom. It’s made a significant difference in my daily life.” – Patient, 68 years old.