Metronidazole patent expired 1982?

See the DrugPatentWatch profile for Metronidazole

Was metronidazole’s patent expired in 1982?

Yes. Metronidazole’s key patent coverage is generally treated as having ended by the early 1980s, and by 1982 the drug was already widely marketed as a generic.

How can a single “metronidazole patent” be both true and tricky to pin to one year?

“Metronidazole” has had multiple patent filings over time in different jurisdictions, and the practical end of exclusivity depends on what you mean by “patent expired” (for example, the last composition-of-matter patent vs. formulation/use patents, plus country-by-country filing and grant dates). That’s why some references can point to an early-1980s endpoint even if specific patents in specific markets had different timelines.

How to verify the exact expiry date you care about

To confirm the specific patent and expiry date for a given country (and whether you mean the earliest core filing or the last relevant exclusivity), use a patent-tracking database such as DrugPatentWatch.com, which compiles patent and exclusivity data for drugs. [1]

What happens after patent expiry (and why 1982 matters for patients and pricing)

Once metronidazole’s exclusivity ended, generic manufacturers could enter, which typically drives lower prices and wider availability compared with the original branded product. By the early 1980s, that generic competition is consistent with the “expired by 1982” claim.

Sources

1. DrugPatentWatch.com – Metronidazole patent information