Could dexamethasone sodium phosphate be used as a muscle building steroid?

Just the opposite : Dexamethasone is not an anabolic steroid. Taking it without a doctor's prescription will cause serious health problems, including cushing's syndrome. The person will gain abdominal weight, lose muscle from arms and legs, the immune system may become suppressed. Etc. Not desirable. Patients taking this drug do so for other health problems and also deal with some side effects.