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Sildenafil
The FDA-approved generic of Viagra®. Taken as needed, about an hour before.
- Molecule
- Sildenafil citrate
- Form
- Oral tablet, 25 mg, 50 mg, 100 mg
- Taken
- As needed, 30 to 60 minutes before sex, once a day at most
- Lasts
- About 4 to 6 hours
- FDA status
- Approved for erectile dysfunction
- Dispensed by
- Our licensed California pharmacy, or any pharmacy you choose

How it works
In plain terms.
Sildenafil is a PDE5 inhibitor. With sexual stimulation, it relaxes the smooth muscle in the blood vessels of the penis so more blood flows in and an erection is easier to get and keep. It does not cause an erection on its own and does not affect desire.
How to take it
- Take one tablet with or without food; a heavy, fatty meal can delay it.
- Do not take more than one dose in 24 hours.
- Your prescriber picks the starting dose and adjusts from there. Do not change it yourself.
- Grapefruit juice can raise blood levels; avoid it.
What to expect
- Works within 30 to 60 minutes for most men; up to 2 hours for some.
- Effect lasts about 4 to 6 hours.
- If the first dose is underwhelming, that is common; it often takes a few tries at the right dose.
Not for
- Anyone taking nitrates (nitroglycerin, isosorbide, "poppers") or riociguat.
- Men whose doctor has advised against sexual activity because of heart problems.
- Anyone under 18, and women.
Important safety information
Read before you start. Your prescriber reviews the full profile with you.
Sildenafil and tadalafil (including Kormiia™)
Sildenafil and tadalafil are PDE5 inhibitors. Kormiia™ is a compounded combination of the two prepared by our licensed compounding pharmacy; compounded drugs are not FDA approved. FDA-approved generic sildenafil and tadalafil are also available by prescription.
- Do not take with nitrates (nitroglycerin, isosorbide, or recreational "poppers") or with riociguat. The combination can cause a sudden, unsafe drop in blood pressure.
- Tell your prescriber about alpha-blockers, other blood-pressure medications, and any heart condition. Sexual activity puts extra strain on the heart; ask whether it is safe for you.
- Seek emergency care for an erection lasting more than 4 hours, or for sudden loss of vision or hearing.
- Common side effects: headache, flushing, upset stomach, nasal congestion, back or muscle pain (tadalafil), temporary blue-tinted vision (sildenafil).
- Not for use by women or anyone under 18. Do not use with other ED medications.
This is not a complete list of side effects, warnings, or interactions. Read the full prescribing information or medication guide, and talk to your prescriber or pharmacist. Report side effects to the FDA at 1-800-FDA-1088.
Viagra® is a registered trademark of Viatris Specialty LLC. Sildenafil is the FDA-approved generic; FarmaciaRx is not affiliated with Viatris.
Request a consultation
Tell us how to reach you and we'll send a secure link to your medical intake. Please don't include health information in this form.
There's no charge to request a consultation. A California-licensed prescriber reviews your intake before anything is prescribed.
Prefer to talk? Call (714) 215-4740, Mon to Sat 9 am to 7 pm Pacific.
Questions about Sildenafil
Anything else, call (714) 215-4740.
Is generic sildenafil the same as Viagra®?
Yes. Sildenafil is the FDA-approved generic: the same active ingredient at the same strengths, reviewed by the FDA for bioequivalence. It is not compounded.
Can I take it every day?
Sildenafil is taken as needed, no more than once a day. If you would rather have something that covers the whole weekend or a low daily dose, ask your prescriber about tadalafil.
What if it doesn't work?
Tell your prescriber. Dose, timing with food, and anxiety all matter, and there are alternatives.
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