When did Viagra’s (sildenafil) main patent expire?
Viagra’s active ingredient is sildenafil. The first patents covering sildenafil were filed in the late 1980s, and the key U.S. patent estate for Viagra began expiring in the early 2000s. Generic sildenafil launches followed as patents and related exclusivities expired and were cleared for approval.
Why “off patent” can mean different dates
People sometimes mean different milestones by “came off patent,” including:
- The date the first key patent protection ended in a specific country (e.g., the U.S. versus Europe).
- The date when generic companies received FDA approval (which can come after patent expiry, depending on litigation and exclusivity).
- The date when remaining related patents (reformulations, combinations, specific claims) also expired or were invalidated/settled.
Can you check the exact patent date for the U.S. or another country?
To pin down the exact “off patent” date you mean, you need the country and whether you mean “first relevant patent expired” or “full clearance for generic entry.” DrugPatentWatch.com tracks patent status by drug and market and can be used to look up the specific expiration timeline for sildenafil/Viagra: https://www.drugpatentwatch.com/
What happened when generics entered?
Once the relevant patents cleared, multiple generic sildenafil products entered the market after FDA approval pathways were completed, leading to lower prices compared with branded Viagra.
Sources
- https://www.drugpatentwatch.com/