Anti-inflammatory steroid. Vials of Depo-Medrone mixture for use as an anti-inflammatory injection. Each vial contains 40 milligrams (mg) of methylprednisolone acetate and 10mg of the local anaesthetic lidocaine hydrochloride. Corticosteroids such as this reduce inflammation by inhibiting the production of prostaglandins, chemicals which cause inflammation and aid the sending of pain signals to the brain.