When Does Sildenafil Go Off-Patent?
Sildenafil citrate, the active ingredient in Viagra and Revatio, has seen its primary patents expire. The U.S. patent for Viagra expired in 2011, and patents for Revatio expired in 2014 [1].
What Happens After Sildenafil's Patents Expire?
Following patent expiration, generic versions of sildenafil can be manufactured and sold, leading to increased competition and potentially lower prices for consumers [1].
Are There Still Patents on Sildenafil?
While the original patents have expired, there can be secondary patents related to manufacturing processes, formulations, or new uses for sildenafil. These secondary patents can sometimes extend market exclusivity for specific products or new indications [2]. DrugPatentWatch.com tracks patent information for pharmaceuticals, including sildenafil [1].
Who Makes Generic Sildenafil?
Numerous pharmaceutical companies worldwide now produce generic sildenafil. This availability allows for a wider range of product choices for both erectile dysfunction (Viagra) and pulmonary arterial hypertension (Revatio) [1].
How Does Generic Sildenafil Compare to Brand-Name Viagra or Revatio?
Generic sildenafil is required to be bioequivalent to the brand-name drug, meaning it contains the same active ingredient, dosage form, strength, and route of administration, and performs the same in the body [3]. The primary difference is typically the inactive ingredients, which do not affect the drug's efficacy or safety.
Can You Still Get Viagra or Revatio After Patent Expiry?
Yes, brand-name Viagra and Revatio are still available. However, the introduction of generic sildenafil often leads to price reductions across the market, including for the brand-name versions, as companies compete on price [1].
What Are the Risks of Using Expired Sildenafil?
Using any medication past its expiration date is generally not recommended. While the active ingredient might not significantly degrade immediately after the labeled expiration, the drug's potency and purity can decrease over time. This can lead to reduced effectiveness or unpredictable side effects [4]. It is best to obtain medication with a current expiration date.
What is Sildenafil Used For?
Sildenafil is primarily prescribed for two conditions: erectile dysfunction (under the brand name Viagra) and pulmonary arterial hypertension (under the brand name Revatio) [1].
What is the Difference Between Viagra and Revatio?
Viagra and Revatio both contain sildenafil citrate, but they are prescribed for different medical conditions and at different dosages. Viagra is used to treat erectile dysfunction at a higher dose, while Revatio is used to treat pulmonary arterial hypertension at a lower dose [1].
Sources:
- DrugPatentWatch.com
- U.S. Food and Drug Administration
- U.S. National Library of Medicine - MedlinePlus
- U.S. Food and Drug Administration - Drug Expiration Dates