Azathioprine + Calcitriol + Methylprednisolone

The combination "azathioprine + calcitriol + methylprednisolone" represents a multi-drug regimen rather than a single branded combination product. Each component has distinct mechanisms of action and uses, though they may be prescribed together in certain clinical scenarios. ## Azathioprine Azathioprine is an immunosuppressant prodrug of 6-mercaptopurine, first synthesized in 1956 by Gertrude Elion, William Lange, and George Hitchings[3]. It's used to treat inflammatory conditions like rheumatoid arthritis and as an immunosuppressant in the prevention of renal transplant rejection[3]. Azathioprine received FDA approval on March 20, 1968[3]. ## Methylprednisolone Methylprednisolone is a corticosteroid used to treat inflammation or immune reactions across various organ systems[1]. Its primary use is to suppress inflammatory and immune responses by regulating the number and function of leukocytes, cytokines, and chemokines[7]. It's commonly prescribed as short-term therapy for acute flares, such as in acute gouty arthritis[7]. ## Combination Use The combination of azathioprine and corticosteroids (like methylprednisolone) has been studied in various conditions: 1. **Rheumatoid Arthritis**: Methylprednisolone pulse therapy in conjunction with azathioprine has shown a short-lasting beneficial effect in persistently active rheumatoid arthritis[2]. 2. **Serpiginous Choroiditis**: When azathioprine is used in combination with corticosteroids, it has been found to be a safe and acceptable option for treating patients with active serpiginous choroiditis[5]. 3. **Renal Transplantation**: Azathioprine was initially used in combination with prednisolone as 'double therapy' for renal transplantation[6]. 4. **Lupus Nephritis**: In severe manifestations of Systemic Lupus Erythematosus, patients are often prescribed methylprednisolone concomitantly with immunosuppressants, and maintenance therapy may include oral prednisolone and azathioprine[7].