Viagra is easily the most well-known medication for erectile dysfunction (ED), with the longest history of any FDA-approved ED treatment on the market today.
If you’ve searched for information about ED medications before, you’ve no doubt seen Viagra mentioned alongside sildenafil. While these two medications might have different names, they are actually the same active ingredient.
The difference is that Viagra is a brand name medication invented and marketed by Pfizer, while sildenafil (or sildenafil citrate) is the active ingredient in Viagra that’s responsible for its positive effects on treating erectile dysfunction.
As a result, assuming both drugs are produced to the same standards, you can expect identical results from a 25-100mg dose of Viagra (the standard dose used for erectile dysfunction) to an identical dose of generic sildenafil.
Sildenafil is also sold as Revatio -- an identical drug to Viagra and generic sildenafil that’s dosed slightly lower and intended to treat pulmonary arterial hypertension.
Viagra vs. Generic Sildenafil
Sildenafil has been available since 1998, when it was approved by the FDA under the product name Viagra as a medication for erectile dysfunction.
Interestingly, sildenafil was originally intended as a treatment for cardiovascular diseases such as pulmonary arterial hypertension, or increased blood pressure in the arteries of the lungs. In some cases, sildenafil is still used today for this purposes.
Pfizer patented sildenafil in 1996 and gained FDA approval to sell the medication in 1998. The patent for Viagra expired in 2012 for countries outside the United States, allowing for the sale of generic sildenafil.
Although Pfizer challenged the expired patent in the United States, sildenafil has since become available as a generic medication and can be manufactured and sold by a variety of companies.
Most generic sildenafil products are labeled as “sildenafil,” although some manufacturers use a different brand name.
Today, sildenafil is available in a variety of forms. It’s most commonly sold in tablet form, with a typical dosage of 20, 25, 50 or 100mg. It’s also available as a cream, capsule and liquid.
Is There Any Difference Between Viagra and Sildenafil?
No. Viagra is the brand name used by Pfizer to market its particular version of sildenafil citrate. There is no chemical difference between the sildenafil used in Pfizer’s branded Viagra tablets and the generic sildenafil available from other manufacturers.
As a general rule, assuming the dose is the same, you will get the same ED treatment effects from a generic form of sildenafil as you will from a Viagra tablet.
It’s worth noting that Viagra comes in several different strengths, with 25mg, 50mg and 100mg tablets available. If you’re switching from Pfizer Viagra to a generic form of sildenafil, check that you’re purchasing tablets with the same dosage as prescribed by your doctor.
With this said, there’s one significant difference between Viagra and generic sildenafil. While a single tablet of Viagra can cost as much as $70 in the United States, generic sildenafil tablets are available for as little as $3 per pill when purchased online.
Important Safety Information
IMPORTANT SAFETY INFORMATION
Do not take Sildenafil (sildenafil citrate) if you:
- take any medicines called nitrates, often prescribed for chest pain, or guanylate cyclase stimulators like Adempas (riociguat) for pulmonary hypertension. Your blood pressure could drop to an unsafe level
are allergic to sildenafil, as contained in Sildenafil and REVATIO, or any of the ingredients in Sildenafil
Discuss your health with your doctor to ensure that you are healthy enough for sex. If you experience chest pain, dizziness, or
nausea during sex, seek immediate medical help
Sildenafil can cause serious side effects. Rarely reported side effects include:
- an erection that will not go away (priapism). If you have an erection that lasts more than 4 hours, get medical help right away.
If it is not treated right away, priapism can permanently damage your penis
- sudden vision loss in one or both eyes. Sudden vision loss in one or both eyes can be a sign of a serious eye problem called
non-arteritic anterior ischemic optic neuropathy (NAION). Stop taking Sildenafil and call your healthcare provider right away if you
have any sudden vision loss
sudden hearing decrease or hearing loss. Some people may also have ringing in their ears (tinnitus) or dizziness. If you have
these symptoms, stop taking Sildenafil and contact a doctor right away
Before you take Sildenafil, tell your healthcare provider if you:
- have or have had heart problems such as a heart attack,
irregular heartbeat, angina, chest pain, narrowing of the aortic valve, or heart failure
- have had heart surgery within the last 6 months
- have pulmonary hypertension
- have had a stroke
- have low blood pressure, or high blood pressure that
is not controlled
- have a deformed penis shape
- have had an erection that lasted for more than 4 hours
- have problems with your blood cells such as sickle cell
anemia, multiple myeloma, or leukemia
- have retinitis pigmentosa, a rare genetic (runs in families)
eye disease
- have ever had severe vision loss, including an eye problem
called NAION
- have bleeding problems
- have or have had stomach ulcers
- have liver problems
have kidney problems or are having kidney dialysis have any other medical conditions
Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins,
and herbal supplements.
Sildenafil may affect the way other medicines work, and other medicines may affect the way Sildenafil works, causing side effects.
Especially tell your healthcare provider if you take any of the following:
- medicines called nitrates
- medicines called guanylate cyclase stimulators such as Adempas (riociguat)
- medicines called alpha-blockers such as Hytrin (terazosin
HCl), Flomax (tamsulosin HCl), Cardura (doxazosin
mesylate), Minipress (prazosin HCl), Uroxatral (alfuzosin HCl),
 Jalyn (dutasteride and tamsulosin HCl), or Rapaflo (silodosin).
Alpha-blockers are sometimes prescribed for prostate
problems or high blood pressure. In some patients, the use
of Sildenafil with alpha-blockers can lead to a drop in blood pressure or to fainting
- medicines called HIV protease inhibitors, such as ritonavir (Norvir), indinavir sulfate (Crixivan), saquinavir (Fortovase or Invirase), or atazanavir sulfate (Reyataz)
- some types of oral antifungal medicines, such as
 ketoconazole (Nizoral) and itraconazole (Sporanox)
- some types of antibiotics, such as clarithromycin (Biaxin),
telithromycin (Ketek), or erythromycin
- other medicines that treat high blood pressure
- other medicines or treatments for ED
Sildenafil contains sildenafil, which is the same medicine found
in another drug called REVATIO. REVATIO is used to treat a
rare disease called pulmonary arterial hypertension (PAH).
 Sildenafil should not be used with REVATIO or with other PAH
treatments containing sildenafil or any other PDE5 inhibitors
(such as Adcirca tadalafil)
Sildenafil does not protect against sexually transmitted diseases, including HIV.
The most common side effects of Sildenafil: headache; flushing; upset stomach; abnormal vision, such as changes in color vision
(such as having a blue color tinge) and blurred vision; stuffy or runny nose; back pain; muscle pain; nausea; dizziness; rash.
Sildenafil (sildenafil citrate) is prescription medicine used to treat erectile dysfunction (ED).
Sildenafil is not for women or children.