doxazosin vs tadalafil
Side-by-side comparison of doxazosin and tadalafil. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
Clinical pharmacology studies have been conducted with coadministration of tadalafil with doxazosin, tamsulosin or alfuzosin.
Recommendation: Your doctor should monitor your blood pressure closely and may need to adjust your doses.
Doxazosin is a medicine that can help lower high blood pressure and improve symptoms of an enlarged prostate in men.
Tadalafil (Cialis) is a medicine that helps men with erectile dysfunction (ED) or enlarged prostate (BPH). It belongs to a class of drugs called PDE5 inhibitors.
Doxazosin is used to treat high blood pressure (hypertension). Lowering blood pressure reduces the risk of strokes and heart attacks. It is also used to treat the symptoms of Benign Prostatic Hyperplasia (BPH), also known as an enlarged prostate, in men.
This medicine can help men who have trouble getting or keeping an erection (ED). It can also treat the symptoms of an enlarged prostate, also known as benign prostatic hyperplasia (BPH). BPH can cause difficulty with urination.
Doxazosin belongs to a class of drugs called alpha-1 adrenergic blockers. It works by relaxing the muscles in the prostate and bladder neck, making it easier to urinate. It also relaxes blood vessels, which helps to lower blood pressure.
Tadalafil works by relaxing the muscles in the penis and prostate. This increases blood flow to these areas. For BPH, it relaxes muscles in the prostate and bladder, which can improve urinary symptoms.
- • Dizziness
- • Feeling tired
- • Low blood pressure
- • Swelling
- • Runny nose
- • Headache
- • Upset stomach
- • Back pain
- • Muscle aches
- • Nasal congestion
- Shortness of breath 1,478
- Feeling unsteady 1,295
- Feeling very tired 1,276
- Loose stools 1,237
- Sudden kidney damage 1,135
- Shortness of breath 11,663
- Headache 10,690
- Diarrhea 7,800
- Feeling sick to your stomach 6,498
- Death 5,896
Doxazosin can cause your blood pressure to drop suddenly when you stand up, leading to dizziness or fainting. This is more likely when you first start taking it or when the dose is increased. If you are having cataract surgery, tell your doctor you are taking this medicine. Doxazosin has been linked to priapism (a painful erection lasting for hours). If this happens, seek medical attention right away.
If you have chest pain, tell your doctor. If you need nitrates for a heart problem, wait 48 hours after taking tadalafil before taking nitrates. If you get an erection that lasts more than 4 hours, get medical help right away. If you have sudden vision loss in one or both eyes, stop taking this medicine and get medical help right away. If you have a sudden decrease or loss of hearing, stop taking this medicine and get medical help right away.
It is not known if doxazosin can harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant. Doxazosin does pass into breast milk in small amounts. Talk to your doctor about the best way to feed your baby if you are taking doxazosin.
This medicine is not for use in women. It is not known if this medicine will harm an unborn baby. It is also not known if this medicine passes into breast milk.
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How to Read This doxazosin vs tadalafil Comparison
doxazosin is classified in the Alpha-1 Adrenergic Blocker drug class, while tadalafil sits within the PDE5 Inhibitor class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, doxazosin has 6,421 submissions while tadalafil has 42,547. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to both of these medications can lower your blood pressure, and taking them together might cause your blood pressure to drop too low.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between doxazosin and tadalafil - always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.