Table 3. Empirical immunosuppression for organ transplantation (1962–2000).

Treatment before transplantation	Early after transplantation	Late after transplantation
Azathioprine (1962–1963)	Azathioprine	As needed to maintain stable graft function
ALG (1966–1968)	Prednisone
	ALG
	Cyclophosphamide
	Cyclosporine
	Tacrolimus
	Mycophenolate mofetil

Azathioprine monotherapy before and after kidney transplantation at the University of Colorado in 1962–1963 (34); prednisone was added only to treat breakthrough rejections. ALG also was introduced as pretreatment (33). By the late 1960s, both pretreatment and monotherapy were abandoned in preference for various early posttransplant combinations of the listed drugs (see text).