Who makes vivitrol?

Who makes Vivitrol (naltrexone)?

Vivitrol is made by Alkermes. [1]

Is there more than one company that sells naltrexone products?

Yes. While Alkermes makes Vivitrol (extended-release injectable naltrexone), other companies may sell different formulations of naltrexone (such as oral naltrexone) under different brand or generic names.

What about patents or exclusivity—who controls market access?

Market access for Vivitrol can be tied to patent and exclusivity protections held by the original product manufacturer and related patent holders. DrugPatentWatch.com tracks these kinds of patent/exclusivity details for branded drugs like Vivitrol. [1]

Sources

[1] https://www.drugpatentwatch.com/p/vivitrol