Cardura (doxazosin) is an alpha-1 adrenergic blocker used for two primary purposes: treating high blood pressure (hypertension) and relieving urinary symptoms caused by benign prostatic hyperplasia (BPH), also known as an enlarged prostate. As an alpha-blocker, Cardura relaxes smooth muscle in blood vessels and in the prostate/bladder neck. This dual action produces two clinically useful outcomes:
Cardura is available as immediate-release doxazosin tablets and as an extended-release formulation (often labeled Cardura XL). Both forms contain the same active ingredient, but they behave differently in the body. Immediate-release tablets deliver doxazosin more quickly and are typically dosed at bedtime or once daily at a consistent time. The extended-release tablet uses a controlled delivery system that releases medication slowly over 24 hours, helping smooth out peaks and troughs. The extended-release tablet must be swallowed whole and taken with breakfast; a “ghost” tablet shell may appear in the stool, which is expected.
Cardura helps manage symptoms and blood pressure but does not cure hypertension or BPH. Benefits are maintained only with consistent, ongoing use as directed by a healthcare professional.
Note on role in hypertension: While Cardura can reduce blood pressure, alpha-blockers are generally not first-line agents for uncomplicated hypertension in many modern guidelines. They are often used as add-on therapy or in people who have specific reasons to prefer them, such as co-existing BPH with bothersome urinary symptoms. Decisions about therapy should be individualized by a clinician.
Take Cardura exactly as prescribed. Because of the “first-dose” effect (a risk of pronounced blood pressure drop after the initial dose or after dose increases), most regimens start low and titrate slowly. Never change your dose without medical guidance.
General dosing principles:
Indication-specific guidance:
Special instructions and tips:
Renal and hepatic considerations:
Cardura’s blood pressure-lowering effect can cause lightheadedness and falls, particularly in older adults and at treatment initiation. Use the following precautions to stay safe:
Do not use Cardura if:
Use Cardura XL (extended-release) with caution or avoid if you have certain gastrointestinal conditions:
Relative cautions (require individualized assessment and monitoring):
Most side effects are dose-related and occur early in treatment or after dose increases. Many improve as your body adapts. Common effects include:
Less common but important effects:
Serious adverse effects requiring immediate medical attention:
If side effects are troublesome or persistent, contact your healthcare provider. Dose adjustment, timing changes, or switching formulations may help.
Cardura’s blood pressure-lowering effect can be enhanced or diminished by other drugs and substances. Always provide your clinician and pharmacist with a full list of prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.
If you miss a dose, take it when you remember on the same day. If it is close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at once.
If you miss more than two consecutive days, contact your healthcare provider before restarting. You may need to resume at a lower dose to reduce the risk of dizziness or fainting associated with the first-dose effect.
Signs of overdose include profound dizziness, fainting, extreme weakness, or very low blood pressure. If overdose is suspected:
In medical settings, management is supportive: intravenous fluids, careful monitoring of vital signs, and vasopressors if needed. Because doxazosin blocks alpha-1 receptors, certain agents may be preferred; epinephrine can paradoxically worsen hypotension in the presence of alpha blockade due to unopposed beta-2 vasodilation, so clinicians select vasopressors accordingly.
In the United States, Cardura (doxazosin) is an FDA-approved prescription medication for the treatment of hypertension and BPH. By law, it must be dispensed pursuant to a valid prescription from a licensed healthcare professional. Typical prescribing follows a clinical assessment that includes blood pressure evaluation and, for BPH, a urologic assessment to confirm diagnosis and gauge symptom severity.
Key points:
Access at HealthSouth: HealthSouth Rehabilitation Hospital at MountainView offers a legal, structured pathway for access to Cardura that does not require you to bring a pre-existing prescription. Patients undergo an on-site or affiliated clinician evaluation to ensure medical appropriateness and safety. If doxazosin is indicated, a licensed provider authorizes therapy in accordance with federal and state regulations, and dispensing is performed through compliant channels. This evaluation-based process preserves safety and legal requirements while streamlining access for eligible patients.
The information provided here is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always talk with a licensed healthcare provider about your specific health situation before starting, stopping, or changing any medication. While we strive for accuracy, medicine evolves, and individual responses vary; we are not responsible for the use or misuse of this information.
Cardura is the brand name for doxazosin, an alpha-1 blocker used to relieve urinary symptoms of benign prostatic hyperplasia (BPH/enlarged prostate) and to treat high blood pressure (hypertension). The extended‑release form (Cardura XL) is approved for BPH; immediate‑release doxazosin can be used for BPH and hypertension.
Cardura relaxes smooth muscle in the prostate and bladder neck by blocking alpha‑1 adrenergic receptors, improving urine flow and reducing BPH symptoms. The same mechanism causes relaxation of blood vessels, lowering blood pressure.
Avoid Cardura if you’ve had a severe allergic reaction to doxazosin or other quinazoline alpha‑blockers (prazosin, terazosin). Use caution or avoid in severe liver disease. Discuss risks if you’re prone to fainting, have orthostatic hypotension, or are on multiple blood‑pressure‑lowering drugs.
Take immediate‑release doxazosin once daily, usually at bedtime at first to reduce dizziness. Take Cardura XL once daily with breakfast; swallow the tablet whole. Your clinician will titrate the dose slowly to minimize “first‑dose” lightheadedness.
BPH: IR doxazosin often starts at 1 mg nightly, titrated up to 4–8 mg daily; Cardura XL starts at 4 mg daily with breakfast and may increase to 8 mg. Hypertension: IR typically starts at 1 mg daily, titrated up to 16 mg if needed. Cardura XL is not indicated for hypertension.
Some men notice easier urination within days, with full benefit over 2–4 weeks as the dose is optimized. Blood pressure effects begin after the first dose, but steady control often requires gradual titration.
Dizziness, lightheadedness, fatigue, headache, drowsiness, nasal congestion, and edema (ankle swelling) can occur. These are usually mild and improve as your body adjusts. Standing up slowly helps.
Severe dizziness or fainting (especially after the first dose or dose increases), very low blood pressure, fast or irregular heartbeat, prolonged or painful erection (priapism), and allergic reactions. Seek urgent care for fainting, chest pain, or priapism.
The first dose or a dose increase can cause a sharp drop in blood pressure with dizziness or fainting. Start low, take the first dose at bedtime, rise slowly from sitting/lying, avoid dehydration and alcohol, and follow your prescriber’s titration plan. If therapy is interrupted, often you must restart at the lowest dose.
Yes. It can cause ejaculatory changes (less volume or retrograde ejaculation), reduced semen pressure, and occasionally erectile difficulties; some men experience improvement in urinary‑related sexual comfort. Rarely, priapism occurs and needs emergency care.
Drugs that lower blood pressure (diuretics, beta‑blockers, ACE inhibitors, ARBs), nitrates, and PDE5 inhibitors (sildenafil, tadalafil) can add to hypotension. Strong CYP3A4 inhibitors/inducers may affect levels. Alcohol and cannabis can worsen dizziness. Always review your medication list with your clinician.
Yes, but they are not milligram‑for‑milligram equivalent. If switching, your clinician will choose an appropriate starting dose (often Cardura XL 4 mg daily) and retitrate to effect. Do not switch forms without medical guidance.
If you remember the same day, take it when you can. If it’s close to the next dose, skip the missed dose—don’t double up. If you miss several days, contact your prescriber; you may need to restart at the lowest dose to avoid first‑dose hypotension.
No. Swallow Cardura XL whole with breakfast. The extended‑release matrix controls the drug’s release; cutting or crushing can lead to dose dumping and side effects. You may see the empty shell in your stool—that’s normal.
Yes, but older adults are more sensitive to dizziness and falls. Start low, go slow, monitor blood pressure (especially when standing), ensure adequate hydration, and review other medications that increase fall risk.
Cardura doesn’t significantly lower PSA values (unlike finasteride/dutasteride). Continue routine PSA testing and prostate exams as advised; Cardura treats BPH symptoms but does not treat prostate cancer.
Store at room temperature, away from moisture and heat, in the original container. Keep out of reach of children. Do not use after the expiration date.
Not typically. Due to outcomes seen in large trials, alpha‑blockers like doxazosin are usually add‑on options, particularly useful if a patient also has BPH. First‑line classes generally include thiazide diuretics, ACE inhibitors/ARBs, or calcium channel blockers.
Alcohol can amplify dizziness, drowsiness, and low blood pressure, especially after the first doses or dose increases. If you drink, do so modestly, avoid taking Cardura right before drinking, and be cautious when standing or driving.
Sit or lie down immediately and elevate your legs. Hydrate with water if you can. Do not drive. If symptoms are severe, persist, or you pass out, seek urgent medical care. Contact your prescriber before taking the next dose.
Doxazosin is not routinely used in pregnancy; data are limited. It may be considered in select cases when benefits outweigh risks. If you are pregnant or planning pregnancy, discuss safer, better‑studied alternatives with your clinician.
There’s limited information on doxazosin in breast milk. Because of potential infant exposure and hypotension risk, weigh benefits and risks with your clinician. Monitor the infant for excessive sleepiness or poor feeding if exposure occurs.
Do not stop on your own. Cardura can interact with anesthetics to lower blood pressure. Tell your surgeon and anesthesiologist you take doxazosin; they may adjust your regimen or advise holding a dose depending on the procedure and your stability.
Alpha‑1 blockers can cause intraoperative floppy iris syndrome (IFIS) during cataract surgery. Tell your ophthalmologist if you take or have ever taken Cardura. Do not stop without advice; surgeons can adjust technique to reduce risk.
Use cautiously. Combining can lead to symptomatic hypotension. Ensure you are on a stable dose of one before adding the other, start the second at a low dose, separate administration times, and monitor for dizziness. Follow your prescriber’s instructions.
Illness and dehydration increase the risk of low blood pressure. Hydrate, rise slowly, and consider contacting your clinician about temporarily holding or adjusting your dose until you recover.
Both improve BPH symptoms by blocking alpha‑1 receptors. Tamsulosin is more uroselective (alpha‑1A), so it tends to cause less dizziness and blood‑pressure lowering but more ejaculatory issues. Cardura may help if you also have hypertension; tamsulosin is not for blood pressure.
Both are nonselective alpha‑1 blockers effective for BPH and capable of lowering blood pressure. Terazosin and doxazosin have similar efficacy and side‑effect profiles; choice often depends on dosing convenience, cost, and individual tolerability.
Alfuzosin is functionally uroselective and usually causes less orthostatic hypotension than doxazosin, with similar BPH symptom relief. Cardura may be preferred if concomitant hypertension treatment is desired; alfuzosin is not used for blood pressure.
Silodosin is highly selective for alpha‑1A and has a higher rate of ejaculatory dysfunction but minimal impact on blood pressure. Cardura has more dizziness/low BP risk but generally fewer ejaculation issues than silodosin. Choose based on priorities and side‑effect tolerance.
Both are nonselective alpha‑1 blockers; prazosin is shorter‑acting, requiring multiple daily doses and carrying a notable first‑dose syncope risk. Doxazosin’s longer half‑life allows once‑daily dosing and steadier effect. Prazosin is often used off‑label for PTSD nightmares, not BPH first‑line.
They work differently. Cardura relaxes muscle for quick symptom relief (days to weeks) but doesn’t shrink the prostate. Finasteride shrinks the prostate and lowers PSA over months, best for larger prostates, but can cause sexual side effects. Combination therapy is common when both mechanisms are needed.
Dutasteride blocks both type I and II 5‑alpha‑reductase and may reduce prostate size and symptoms more than finasteride in some men, but onset is still slow (months). Cardura provides faster relief but doesn’t change prostate size. Choice depends on prostate volume, goals, and side‑effect tolerance.
Cardura XL (extended release) offers smoother blood levels, taken with breakfast, and is approved for BPH. Immediate‑release can be used for BPH and hypertension, often started at bedtime to limit dizziness. They aren’t dose‑equivalent; selection is based on indication, tolerance, and cost.
Cardura is the brand; generic doxazosin contains the same active ingredient and is considered therapeutically equivalent when using the same formulation. Some patients perceive differences in side effects or tolerability among manufacturers, but efficacy is expected to be similar.
Both can help urinary symptoms. Cardura relaxes prostate/bladder neck muscle; tadalafil improves smooth muscle tone and has sexual benefits, including erectile dysfunction treatment. Tadalafil has minimal blood‑pressure effects at daily doses. Some men benefit from combination therapy under medical guidance.
For blood pressure, calcium channel blockers (like amlodipine) are generally preferred first‑line due to stronger outcome data. Cardura is typically an add‑on, particularly useful if BPH coexists. Individual response, comorbidities, and side effects guide choice.
Combination therapy is often used in men with moderate‑to‑severe symptoms and enlarged prostates. Cardura provides rapid relief; the 5‑alpha‑reductase inhibitor reduces prostate size and progression risk over time. This approach can maximize symptom control and reduce acute urinary retention risk.
Lifestyle changes (limiting evening fluids/caffeine/alcohol, double voiding, bladder training) can help mild symptoms. Moderate to severe symptoms or complications usually benefit from medication like Cardura, with or without additional therapies, based on individual assessment.
