Formy epidural steroid inj, my dr said he used a powder that he mixed into a solution. why are doctors here saying that "steroid powder" doesn't exist?

Compounding pharmacy: It maybe the case that compounding pharmacies make steroid solution from steroid powder. However to my knowledge in clinical practice all steroid for injection is purchased as a solution.

Depends: Not sure where "here" is but in the us epidural steroid injections are either done with a clear solution of dissolved steroid such as Dexamethasone or a "suspension" of steroids in liquid such as triamcinolone and methyl prednisolone. The susoensions are a powder suspended in liquid but do not need to be mixed up in solution as they come already in the suspension. Not sure about other countries.

It exists.: Kenalog, (triamcinolone) Celestone, Depo-medrol are all steroids that are mounted to a powder that allows them to be long acting steroids. These powder based steroid often have to be shaken into a mixture so that the solutions that is injected is evenly mixed.