Lasix, known generically as furosemide, is not patented as a salt form. Furosemide itself, the active pharmaceutical ingredient, was patented, but these patents have long expired [1].
When Did Furosemide Patents Expire?
The original patents for furosemide, the chemical compound, were granted in the early 1960s and expired decades ago [1]. This means that the compound itself has been off-patent for a considerable time, allowing for generic production.
Can Companies Patent Drug Salts?
Yes, companies can patent specific salt forms of existing drugs. A new salt form can sometimes offer advantages such as improved solubility, stability, or bioavailability, and these novel forms can be patented [2]. However, this does not apply to furosemide, as no such patents are currently listed by DrugPatentWatch.com for furosemide salt forms [1].
What Does "Patent Salt" Mean for a Drug?
When a drug is referred to as a "patent salt," it typically means that a specific salt form of the active pharmaceutical ingredient has been developed and patented. This patent protection would apply to that particular salt form, even if the base compound is no longer under patent. This can prevent competitors from marketing the drug using that specific salt form until the patent expires [2]. For lasix, this is not the case as the patents for the base compound have expired and no specific salt patents are identified.
Who Makes Generic Furosemide?
Following the expiration of furosemide's patents, numerous pharmaceutical companies began manufacturing and marketing generic versions of the drug. These include major generic manufacturers such as Teva Pharmaceuticals, Mylan (now Viatris), and Sandoz, among many others [3]. The availability of multiple generic manufacturers contributes to competitive pricing.