Cardura

Cardura (doxazosin mesylate) is an alpha-1 adrenergic blocker medication prescribed for the management of hypertension (high blood pressure) and the symptomatic treatment of benign prostatic hyperplasia (BPH). It functions by relaxing blood vessels and muscles in the prostate and bladder neck, facilitating easier blood flow and improved urinary function. This dual-action mechanism makes it a versatile option in a clinician’s arsenal for addressing cardiovascular and urological conditions. Proper diagnosis and adherence to a prescribed treatment plan are essential for achieving optimal therapeutic outcomes.

Features

• Active pharmaceutical ingredient: Doxazosin mesylate.
• Available in scored tablet formulations for ease of dose titration (1 mg, 2 mg, 4 mg, 8 mg).
• Selective antagonist of postsynaptic alpha-1 adrenergic receptors.
• Exhibits a dual therapeutic action for hypertension and BPH.
• Standard oral administration, typically once daily.

Benefits

• Effectively lowers elevated blood pressure, reducing the long-term risk of associated cardiovascular events.
• Provides rapid relief from obstructive and irritative symptoms of BPH, improving urinary flow and reducing nocturia.
• Offers a convenient once-daily dosing regimen, promoting patient adherence to the treatment plan.
• Does not adversely affect blood lipid profiles or blood glucose levels, which is beneficial for patients with metabolic comorbidities.
• Can be used as a monotherapy or in combination with other antihypertensive agents (e.g., diuretics, beta-blockers, ACE inhibitors) for synergistic effects.

Common use

Cardura is primarily indicated for two conditions. First, it is used in the management of hypertension, either as monotherapy or as part of a combination antihypertensive regimen. It works by causing peripheral vasodilation, which reduces peripheral vascular resistance and lowers blood pressure. Second, it is used for the treatment of the signs and symptoms of benign prostatic hyperplasia (BPH). In BPH, it relaxes the smooth muscle in the prostate and bladder neck, which decreases the dynamic component of bladder outlet obstruction. This leads to an improvement in urine flow rate and a reduction in symptoms such as hesitancy, weak stream, incomplete emptying, nocturia, and urgency. It is important to note that while Cardura improves symptoms, it does not reduce the size of the enlarged prostate itself.

Dosage and direction

The dosage of Cardura must be individualized based on the patient’s therapeutic response and tolerability.

For Hypertension: The initial dose is 1 mg administered once daily. The dose may be increased after 1–2 weeks of therapy to 2 mg once daily. Thereafter, doses may be increased further, if necessary, at intervals of 1–2 weeks to 4 mg, 8 mg, and finally to a maximum of 16 mg once daily to achieve the desired blood pressure response. The majority of patients who respond to Cardura will do so at a dose of 4 mg or less per day.

For Benign Prostatic Hyperplasia: The initial dose is also 1 mg administered once daily. The dose should be titrated upwards to 2 mg, 4 mg, and 8 mg once daily, with the next dose increment typically occurring at 1–2 week intervals. The recommended therapeutic dosage range is 4–8 mg once daily. Doses above 4 mg provide no additional symptomatic relief but increase the incidence of postural side effects.

Administration: Cardura tablets should be swallowed whole, with a sufficient amount of water. They can be taken with or without food. Administration at bedtime is often recommended, especially during initial dose titration, to minimize the potential for orthostatic hypotension and syncope (fainting). Patients should not crush or chew the tablets.

Precautions

First-Dose Effect: A marked drop in blood pressure, primarily orthostatic hypotension, with syncope (fainting) can occur within 30 to 90 minutes after the first dose or after any subsequent rapid dose increase. This risk is also increased if therapy is interrupted for several days and then restarted. To avoid this, initiation of therapy with 1 mg and careful dose titration are mandatory. Patients should be cautioned about engaging in potentially hazardous activities during this period.

Orthostatic Hypotension: While syncope is most common with the first dose, symptoms of lowered blood pressure, such as dizziness, lightheadedness, and palpitations, can occur at any time during treatment, particularly after a dose increase. Patients should be advised to sit or lie down if these symptoms occur and to rise slowly from a sitting or lying position.

Priapism: Although very rare, prolonged and painful erections (priapism) have been reported with this class of drugs. This condition requires immediate medical attention to prevent permanent erectile dysfunction.

Cataract Surgery: A complication known as Intraoperative Floppy Iris Syndrome (IFIS) has been observed during cataract surgery in some patients treated with alpha-1 blockers. Ophthalmologists should be informed in advance of planned surgery that the patient is taking doxazosin.

Use in Specific Populations:

• Hepatic Impairment: Cardura should be administered with caution to patients with evidence of impaired liver function.
• Renal Impairment: Dose adjustment is not routinely needed in patients with renal impairment; however, these patients should be monitored closely, as the drug is extensively metabolized by the liver.
• Geriatric Patients: Elderly patients may be more sensitive to the hypotensive effects of Cardura.

Contraindications

Cardura is contraindicated in patients with a known hypersensitivity to doxazosin, other quinazolines (e.g., prazosin, terazosin), or any component of the formulation. It is also contraindicated in patients with a history of orthostatic hypotension and should not be used for the treatment of BPH in patients with hypotension.

Possible side effect

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

Very Common (≥1/10) and Common (≥1/100 to <1/10):

• Dizziness, headache, vertigo
• Fatigue, asthenia (weakness), somnolence (drowsiness)
• Postural dizziness, postural hypotension
• Edema (swelling), particularly peripheral edema

Uncommon (≥1/1,000 to <1/100):

• Palpitations, tachycardia (rapid heart rate)
• Nausea, dry mouth, diarrhea, constipation
• Rhinitis (nasal inflammation), epistaxis (nosebleeds)
• Blurred vision
• Urinary incontinence

Rare (≥1/10,000 to <1/1,000):

• Syncope (fainting)
• Priapism
• Allergic reactions including rash, pruritus (itching), urticaria (hives)
• Hepatitis, jaundice

Patients should report any persistent or severe side effects to their healthcare provider.

Drug interaction

The hypotensive effects of Cardura can be potentiated by concomitant use of other antihypertensive agents, including phosphodiesterase-5 (PDE-5) inhibitors (e.g., sildenafil, tadalafil, vardenafil), which are used for erectile dysfunction. This combination can lead to significant hypotension and is generally not recommended. Concomitant administration of Cardura with a strong CYP3A4 inhibitor (e.g., ketoconazole, itraconazole, ritonavir) may increase doxazosin plasma concentrations and should be approached with caution. Non-steroidal anti-inflammatory drugs (NSAIDs) and sympathomimetics may reduce and increase the hypotensive effects of Cardura, respectively. Patients should always inform their doctor of all other medications, including over-the-counter drugs and herbal supplements, they are taking.

Missed dose

If a dose is missed, it should be taken as soon as remembered on the same day. If it is not remembered until the next day, the missed dose should be skipped, and the regular dosing schedule resumed. The patient should never take a double dose to make up for a forgotten one, as this could significantly increase the risk of hypotension and syncope.

Overdose

In the event of an overdose, the primary expected manifestation is severe hypotension, which may present as dizziness, lightheadedness, and syncope. Supportive measures should be initiated, including placing the patient in a supine position and elevating their legs. This position is essential for managing shock and restoring blood pressure. Vital signs should be monitored frequently. If necessary, volume expansion with intravenous fluids and vasopressor therapy may be used to support blood pressure. Gastric lavage may be considered if ingestion was recent. As doxazosin is highly protein-bound, dialysis is not likely to be of benefit.

Storage

Cardura tablets should be stored at room temperature, between 15°C and 30°C (59°F and 86°F), in their original container to protect them from light and moisture. The medication must be kept out of sight and reach of children and pets. Do not use the medicine after the expiration date printed on the packaging. Unused medication should not be disposed of via wastewater or household waste; consult a pharmacist on the proper disposal method according to local guidelines.

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 medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The information provided may not cover all possible uses, directions, precautions, drug interactions, or adverse effects.

Reviews

• “As a urologist with over 20 years of experience, I find Cardura to be a highly effective first-line option for managing BPH symptoms. The titration process is key to minimizing initial side effects, and most of my patients achieve significant symptomatic relief on a stable 4 mg dose. The improvement in flow rate and reduction in nocturia are consistently notable.” – Dr. A. Reynolds, MD
• “In my cardiology practice, I often use Cardura as part of a combination therapy regimen for resistant hypertension. Its mechanism of action complements other drug classes well. While the first-dose effect requires careful patient education, its long-term efficacy and neutral metabolic profile are substantial benefits, especially for hypertensive patients with concomitant BPH.” – Dr. L. Chen, Cardiologist
• “I’ve been on Cardura for my blood pressure for three years. The first few days I felt a bit dizzy, but that passed quickly. My numbers have been consistently excellent since, and I haven’t experienced any other side effects. The once-a-day pill is easy to remember.” – Patient M, 68
• “Prescribed for BPH. The difference in urinary frequency and urgency was noticeable within two weeks. It has greatly improved my sleep as I’m not getting up multiple times a night. A game-changer for my quality of life.” – Patient R, 72