Cardura (doxazosin) is a long-established alpha-1 adrenergic blocker used to relieve urinary symptoms of benign prostatic hyperplasia and as an adjunctive option for hypertension in selected adults. Its dual action—relaxing smooth muscle in the prostate/bladder neck and dilating peripheral arteries—underpins both indications. Below you’ll find practical, clinician-informed guidance on uses, dosing, precautions, side effects, interactions, storage, and U.S. prescription policies to help you discuss Cardura confidently with your healthcare provider.
Cardura is primarily prescribed for benign prostatic hyperplasia (BPH). By selectively blocking alpha-1 receptors in the prostate and bladder neck, it reduces smooth muscle tone, thereby improving urinary flow and reducing symptoms such as weak stream, hesitancy, straining, incomplete emptying, urgency, and nocturia. Many patients notice improvement in urinary symptoms within days to weeks, with maximal benefits as the dose is optimized. Cardura does not shrink the prostate; rather, it relaxes muscle around it. For prostate size reduction, clinicians may pair Cardura with a 5-alpha-reductase inhibitor (for example, finasteride) when appropriate.
Cardura also has an antihypertensive effect by relaxing vascular smooth muscle and lowering systemic vascular resistance. While no longer a first-line agent for most patients with high blood pressure, doxazosin can be considered as add-on therapy, especially in patients with concomitant BPH. Your clinician will consider overall cardiovascular risk, current regimen, and potential benefits for urinary symptoms when deciding whether to include Cardura in your hypertension plan.
Because of the well-known “first-dose phenomenon” (lightheadedness or fainting due to an initial drop in blood pressure), Cardura is usually started low and increased gradually. For BPH, immediate-release doxazosin often starts at 1 mg once daily, then titrates at intervals (for example, to 2 mg, 4 mg, and possibly 8 mg daily) based on symptom relief and tolerability. The extended-release tablet (Cardura XL) is commonly initiated at 4 mg once daily with breakfast and may be increased to 8 mg if needed. Do not crush, chew, or split extended-release tablets; they are designed for slow delivery through the gastrointestinal tract.
In hypertension, initial dosing is typically 1 mg once daily, with careful upward titration according to blood pressure response. Maximum daily doses may vary by formulation; your clinician will individualize the target. Take Cardura at the same time each day, and many prescribers recommend bedtime dosing—especially for the first doses—to minimize the chance of dizziness or falls. If therapy is interrupted for several days, it is often prudent to restart at the lowest dose and re-titrate. Always follow prescriber instructions and check your blood pressure regularly during dose adjustments.
Orthostatic hypotension (a drop in blood pressure upon standing) is the key precaution with Cardura. Dizziness, lightheadedness, and fainting are more likely at the start of therapy, after a dose increase, or when combined with other blood pressure–lowering agents, phosphodiesterase type 5 (PDE5) inhibitors, or alcohol. Rise slowly from sitting or lying positions, especially at night. Until you know how Cardura affects you, avoid driving, operating machinery, climbing ladders, or situations where a fall could cause injury. Staying hydrated, limiting alcohol, and taking the first dose at bedtime can reduce risk.
If you have cataracts and ever plan eye surgery, inform your ophthalmologist that you are taking or have taken an alpha-1 blocker like doxazosin. Intraoperative floppy iris syndrome (IFIS) has been observed with alpha-1 blockers during cataract procedures, and surgeons can adjust their technique if they know your medication history. Additional cautions include hepatic impairment (because doxazosin is metabolized by the liver), heart failure or significant edema, and concurrent use of other alpha-1 blockers. Routine prostate cancer screening should continue for BPH patients, as symptom relief does not rule out malignancy.
Cardura is contraindicated in individuals with known hypersensitivity to doxazosin, other quinazoline-derived alpha-1 antagonists (such as prazosin or terazosin), or any component of the formulation. Use is generally avoided or undertaken with great caution in severe hepatic impairment. Discuss pregnancy and breastfeeding with your clinician; while Cardura is not typically used in these populations, risk–benefit decisions are individualized. Patients with a history of recurrent syncope, severe orthostatic hypotension, or certain cardiac conditions require careful evaluation before starting therapy.
Common side effects include dizziness, lightheadedness, headache, fatigue, drowsiness, nasal congestion, and edema (swelling in the ankles or feet). Some individuals may experience nausea or abdominal discomfort. These effects are often most pronounced early in treatment or after dose increases and may lessen as the body adjusts. Taking the dose at bedtime, rising slowly, and staying hydrated can help. If symptoms remain bothersome or worsen, contact your healthcare provider to consider dose adjustments or alternative therapies.
Less common but serious effects can include pronounced hypotension with fainting, palpitations, chest pain, shortness of breath, or an irregular heartbeat. Priapism (a prolonged, painful erection) is a rare urologic emergency requiring immediate medical attention. Allergic reactions—rash, itching, swelling, severe dizziness, breathing difficulty—warrant urgent evaluation. Any new or concerning symptoms, especially those impacting balance, vision, or cardiovascular stability, should prompt timely medical review.
Cardura’s blood pressure–lowering effect can be amplified by other antihypertensives, nitrates, diuretics, or alcohol, increasing the risk of dizziness or fainting. Combining Cardura with other alpha-1 blockers (for example, tamsulosin, terazosin) is typically avoided due to additive effects without proportional benefit. When adding Cardura to a multi-drug regimen, clinicians often adjust other medications and monitor blood pressure closely to maintain safety and efficacy.
PDE5 inhibitors for erectile dysfunction (such as sildenafil, tadalafil, or vardenafil) may potentiate hypotension when taken with doxazosin. If both are necessary, prescribers usually recommend a stable alpha-blocker regimen first, then the lowest possible PDE5 inhibitor dose with careful timing and monitoring. Doxazosin is metabolized primarily via CYP3A4; strong inhibitors (for example, certain azole antifungals or macrolide antibiotics) may increase exposure, while inducers could reduce effectiveness. Your pharmacist can flag potential interactions based on your full medication list.
Nonsteroidal anti-inflammatory drugs (NSAIDs) may blunt antihypertensive responses in some patients. Herbal supplements with blood pressure effects (for example, hawthorn, yohimbine, or high-dose L-arginine) can introduce unpredictability. Provide your clinician with a complete list of prescription drugs, over-the-counter products, and supplements so your regimen can be optimized safely.
If you miss a dose of Cardura, take it when you remember unless it is close to the time of your next dose. If it’s nearly time for the next dose, skip the missed dose and resume your usual schedule—do not double up. Because of the first-dose effect, if you skip Cardura for several days, contact your prescriber before restarting; you may need to resume at the lowest dose and re-titrate to reduce the risk of orthostatic hypotension.
Overdose can cause profound hypotension, dizziness, fainting, lethargy, or shock. If an overdose is suspected, seek emergency medical care. Initial management typically includes placing the person supine with legs elevated, monitoring vital signs and cardiac rhythm, and administering IV fluids. In some cases, vasopressors and other supportive measures may be required. Activated charcoal may be considered if ingestion is recent and the patient is stable. Because doxazosin is highly protein bound, dialysis is unlikely to be helpful. Bring the medication container to the emergency department if possible.
Store Cardura tablets at room temperature (generally 20–25°C or 68–77°F), protected from moisture and excessive heat. Keep the medication in its original container with the lid tightly closed, and out of reach of children and pets. Do not use tablets that are chipped, discolored, or expired. Never crush or split extended-release tablets, as this can alter drug delivery. Dispose of unused medication responsibly per local guidance or through pharmacy take-back programs.
In the United States, Cardura (doxazosin) is a prescription-only medication. Purchasing it without a valid prescription is unlawful and unsafe. That said, there are legitimate pathways that reduce friction for patients: many pharmacies and platforms offer integrated telehealth services, where a licensed clinician evaluates your symptoms, reviews your medical history, and, if appropriate, issues a valid prescription that is then fulfilled by a licensed pharmacy. This ensures clinical oversight, appropriate dosing, and screening for interactions and contraindications—critical for an alpha-1 blocker with blood-pressure effects.
Nunzia Pharmaceutical provides a structured, compliant route for accessing Cardura by connecting patients with licensed healthcare professionals and verified pharmacy partners. Rather than bypassing safeguards, Nunzia emphasizes legality and safety: clinician evaluation, prescription verification, transparent pricing, and secure fulfillment. If you see claims anywhere that you can “buy Cardura without prescription,” treat them with caution. The safe, legal alternative is a streamlined telehealth pathway that results in a legitimate prescription when medically appropriate. This protects you from counterfeit or substandard products, reduces the risk of dangerous interactions, and aligns with federal and state regulations. For specific availability, insurance options, and shipping timelines, contact Nunzia’s support team or your local pharmacist, and always use Cardura under the direction of a licensed healthcare provider.
Cardura is the brand name for doxazosin, an alpha-1 adrenergic blocker prescribed for benign prostatic hyperplasia (BPH) and, less commonly today, hypertension. It relaxes smooth muscle in the prostate and bladder neck to improve urine flow and lowers blood pressure by dilating blood vessels.
By selectively blocking alpha-1 receptors in the prostate and bladder neck, doxazosin reduces smooth muscle tone, decreasing urinary obstruction and easing symptoms such as weak stream, hesitancy, and nocturia.
Some patients notice easier urination within a few days, but full benefit typically develops over 2–4 weeks as the dose is titrated. Consistent daily use is important.
Most modern guidelines do not recommend alpha-1 blockers like doxazosin as first-line therapy for hypertension due to outcome data; they may be used as add-on therapy, especially when BPH is also present.
Cardura is immediate-release doxazosin taken once daily, often at bedtime during titration; Cardura XL is extended-release taken once daily with breakfast. XL provides steadier blood levels and may reduce peak-related dizziness. Cardura XL tablets should not be split or crushed.
Dizziness, lightheadedness, fatigue, headache, nasal congestion, edema (swelling), and palpitations are common. Orthostatic hypotension (blood pressure drop on standing) is dose-related and most likely after the first dose or dose increases.
The first dose can cause pronounced dizziness or fainting due to a sudden drop in blood pressure. Start at a low dose, take it at bedtime, rise slowly from sitting or lying positions, avoid alcohol, and follow your clinician’s titration schedule.
Severe dizziness or fainting, chest pain, shortness of breath, fast or irregular heartbeat, persistent or painful erections (priapism), yellowing of skin/eyes, or sudden swelling of hands/feet warrant immediate medical attention.
For BPH, typical starting dose is 1 mg once daily (IR) or 4 mg once daily with breakfast (XL), titrated to effect up to 8 mg daily. For hypertension, start at 1 mg once daily and titrate based on blood pressure and tolerability. If therapy is interrupted for several days, re-start at the lowest dose and retitrate.
Doxazosin can be prescribed to adult women for hypertension when appropriate, but it is not indicated for BPH. Safety in pregnancy and breastfeeding is not well established; decisions are individualized with a clinician.
Use caution with PDE5 inhibitors (sildenafil, tadalafil, vardenafil), other antihypertensives, and other alpha blockers due to additive blood pressure lowering. Strong CYP3A4 inhibitors (e.g., clarithromycin, ketoconazole) may increase doxazosin exposure. Alcohol can amplify dizziness. Always review a full medication list with your clinician.
Yes, but there is an increased risk of symptomatic hypotension. Start the ED drug at the lowest dose, separate dosing by several hours, and avoid taking new or higher doses of both on the same day without medical guidance.
Take it when you remember unless it’s close to your next dose; do not double up. If you’ve missed several days, contact your clinician—restarting at a lower dose may be necessary to avoid dizziness or fainting.
No, alpha-1 blockers do not change prostate size; they relax muscle to improve flow. Medications like finasteride or dutasteride reduce prostate volume over months, but they are a different drug class.
Alpha-1 blockers are associated with intraoperative floppy iris syndrome (IFIS). If you are taking or have ever taken doxazosin, tell your ophthalmologist before cataract surgery so they can plan techniques to reduce risk.
Compared with uroselective agents, doxazosin has a lower rate of ejaculatory dysfunction but can still cause sexual side effects. Dizziness and fatigue may also impact sexual performance. Report persistent issues to your clinician.
Until you know how doxazosin affects you, avoid driving or operating machinery, especially after the first dose or dose increases, due to possible dizziness or fainting.
Alpha blockers can facilitate stone passage by relaxing ureteral smooth muscle. Tamsulosin is most studied; doxazosin has also been used off-label. Choice depends on clinician preference, side-effect profile, and patient factors.
Older adults, those with low baseline blood pressure, dehydration, heart failure, or significant liver impairment. People at high fall risk should be monitored closely during initiation and titration.
Store at room temperature away from moisture and heat, in the original container, and out of reach of children.
Tamsulosin is more uroselective, so it tends to cause less blood pressure lowering and dizziness but more ejaculatory dysfunction. Doxazosin improves urinary symptoms similarly but has greater risk of orthostatic hypotension; it may be preferred if concomitant hypertension is a target.
Both are nonselective alpha-1 blockers effective for BPH and can reduce blood pressure. Doxazosin typically offers once-daily dosing with a long half-life; terazosin is also once nightly but may require slower titration. Side effects are similar; choice depends on tolerability, cost, and clinician experience.
Alfuzosin is functionally uroselective and generally has less impact on blood pressure than doxazosin, which may mean fewer dizziness and fall events in some patients. Alfuzosin is taken once daily with food; ejaculatory side effects are less common than with tamsulosin but may occur.
Silodosin is highly uroselective, with minimal blood pressure effects but a higher rate of ejaculatory dysfunction. Doxazosin is more likely to cause orthostatic hypotension but may have fewer sexual side effects. Silodosin requires renal dosing adjustments.
For BPH, doxazosin is generally preferred over prazosin due to longer duration and once-daily dosing. Prazosin often requires multiple daily doses and has a prominent first-dose effect. Prazosin is also used off-label for PTSD-related nightmares, which is not a typical use for doxazosin.
Both are once-daily. Cardura XL provides smoother doxazosin levels and may reduce peak-related dizziness, but tamsulosin remains more uroselective with less blood pressure impact overall. Symptom relief is comparable; side-effect profiles drive choice.
Uroselective agents such as tamsulosin, silodosin, or alfuzosin generally have less systemic blood pressure effect than doxazosin or terazosin. Discuss fall risk and orthostatic symptoms with your clinician.
Yes, doxazosin can address both conditions. However, because alpha blockers are not first-line for hypertension, clinicians often combine or prioritize other antihypertensives depending on cardiovascular risk and guideline recommendations.
No, combining alpha-1 blockers is generally avoided due to additive hypotension without added urinary benefit. If one is ineffective or poorly tolerated, switching within the class is considered rather than combining.
Both can cause orthostatic hypotension and falls. Doxazosin’s longer half-life allows once-daily dosing but can prolong side effects. Slow titration, bedtime dosing, and careful monitoring are crucial with either medication in older adults.
Alfuzosin typically has less blood pressure lowering than doxazosin, which may make it easier to co-administer with PDE5 inhibitors. Regardless of choice, start low, separate doses by several hours, and monitor for dizziness.
Silodosin has higher rates of anejaculation and reduced semen volume. Doxazosin more often causes dizziness than ejaculatory issues. Patient preference and priorities (sexual function versus fall risk) guide selection.
Neither is preferred first-line for blood pressure. If an alpha blocker is considered as add-on therapy, doxazosin’s once-daily dosing and longer half-life make it more practical than prazosin, but other classes usually offer better cardiovascular outcomes.
Both can promote stone passage; tamsulosin has the strongest evidence base. Doxazosin is a reasonable alternative when tamsulosin is not suitable, though it may cause more systemic blood pressure effects.
All are available as generics. Local pricing varies, but doxazosin and terazosin are typically inexpensive. Extended-release formulations like Cardura XL may cost more than immediate-release versions.
Among the class, uroselective agents (tamsulosin, silodosin, alfuzosin) generally produce less orthostatic hypotension than doxazosin or terazosin, though individual response varies.