The primary defendants in the Depo-Provera litigation are Pfizer Inc., the original manufacturer and marketer of Depo-Provera, and Viatris Inc., which currently distributes the product. Some lawsuits may also name generic manufacturers that produce medroxyprogesterone acetate injections under different brand names. The legal actions target these pharmaceutical companies based on allegations of failure to warn about known risks, inadequate safety testing and post-market surveillance, negligent misrepresentation of the product's safety profile, and breach of implied warranties regarding the product's safety. The lawsuits seek to hold these corporate entities accountable for injuries that plaintiffs allege could have been prevented with proper warnings and safety communications.