sildenafil vs tadalafil
Side-by-side comparison of sildenafil and tadalafil Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Viagra, Revatio
Cialis
Sildenafil is a medicine used to treat erectile dysfunction (ED) in men. It helps increase blood flow to the penis to get and keep an erection.
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.
Sildenafil is used to treat erectile dysfunction (ED), also known as impotence, in men. ED is when you cannot get or keep an erection firm enough for sex. Sildenafil helps by increasing blood flow to the penis when you are sexually stimulated.
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.
Sildenafil belongs to a class of drugs called PDE5 inhibitors. It works by relaxing the muscles and increasing blood flow to the penis during sexual stimulation. This helps you get and keep an erection.
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.
- • Headache
- • Flushing (redness of the skin)
- • Upset stomach
- • Abnormal vision (blurred vision, changes in color vision)
- • Nasal congestion (stuffy nose)
- • Headache
- • Upset stomach
- • Back pain
- • Muscle aches
- • Nasal congestion
- Shortness of breath 7,729
- Headache 5,655
- Diarrhea 4,447
- Nausea 3,984
- Death 3,872
- Shortness of breath 11,663
- Headache 10,690
- Diarrhea 7,800
- Feeling sick to your stomach 6,498
- Death 5,896
You should not take sildenafil if you are taking nitrates for chest pain, as this can cause a dangerous drop in blood pressure. If you have an erection that lasts longer than 4 hours, get medical help right away. Stop taking sildenafil and seek medical attention if you have a sudden loss of vision or hearing.
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.
Sildenafil is not for use in women. It is not known if sildenafil can harm an unborn baby or pass into breast milk.
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.
How to Read This sildenafil vs tadalafil Comparison
sildenafil is classified in the PDE5 Inhibitor drug class, while tadalafil sits within the PDE5 Inhibitor class. Because both drugs share the same classification, they are often considered interchangeable in theory — but clinical outcomes rarely track that cleanly. 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, sildenafil has 25,687 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. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. 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 sildenafil 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.