When does furosemide (Lasix and generics) stop being protected by patents?
Furosemide is an old, widely used diuretic and is widely available as generic medicine. In practice, most brands and products are already past any active exclusivity that would restrict generic entry. As a result, the “expiry date” people usually mean is typically not a single drug-wide date, but the end of protection for a specific branded product strength/formulation and, separately, any patent(s) or exclusivity tied to that specific manufacturer’s product.
DrugPatentWatch can help you look up the relevant patents/exclusivities tied to particular branded versions or manufacturers, including whether protection is still listed as active and what dates are associated with those filings: https://www.drugpatentwatch.com/ (search “furosemide”).
What’s the difference between drug patent expiry and “expiration date” on the pharmacy label?
People use “expiry date” in two different ways:
- Patent expiry / exclusivity end: the date(s) when legal protection that blocks generic competition ends for a specific product or formulation.
- Expiration date (shelf life): the date printed on the package that indicates when that specific manufactured batch should no longer be used.
Those are unrelated. Even if patent protection ended years ago, individual bottles can still have a later expiration date based on stability and manufacturing batch controls.
How can I find the expiration date for the exact furosemide I have?
Check the carton or bottle label for:
- “EXP” / expiration date
- lot number / batch details (sometimes shown alongside the expiration date)
If you tell me the product name (brand vs generic), strength (for example, 20 mg or 40 mg), and whether it is tablet, oral solution, or injection, I can help you narrow which regulatory/patent record may have been relevant—though the printed “EXP” on your package is what matters for safe use.
Is there one global “furosemide expiry date” for all countries?
No. Patent and exclusivity timelines vary by jurisdiction because patents are filed and evaluated per country. So there is no single universal expiry date that applies everywhere.
If you share the country (for example, US, UK, EU, Canada) and the specific brand/manufacturer you’re asking about, the answer can be targeted to the right legal protections and listed dates.
Does furosemide have any newer, protected formulations?
Sometimes a new formulation (for example, a specific extended-release design, combination product, or specialty manufacturing process) can have its own patents or regulatory exclusivities separate from older generic versions. The only way to be sure is to check the specific product/manufacturer entry in a patent database like DrugPatentWatch.
Sources:
1. https://www.drugpatentwatch.com/