Information about Azathioprine
Azathioprine is a purine analogue and prodrug of mercaptopurine that is used as an immunosuppressive agent in organ transplantation to prevent rejection and in autoimmune diseases as a corticosteroid sparing agent.
Liver safety of Azathioprine
Azathioprine is associated with minor, usually transient and asymptomatic elevations in serum aminotransferase levels during therapy and with rare instances of acute, cholestatic liver injury and, with long term use, noncirrhotic portal hypertension as a result of nodular regenerative hyperplasia or sinusoidal obstruction syndrome.
Mechanism of action of Azathioprine
Azathioprine (ay" za thye' oh preen) is an imidazolyl derivative and prodrug of mercaptopurine that inhibits lymphocyte function by antagonism of purine metabolism, thus inhibiting DNA, RNA and subsequent protein synthesis. Azathioprine inhibits the maturation of T cells and blocks delayed hypersensitivity reactions; it also has antiinflammatory activity.
FDA approval information for Azathioprine
Azathioprine was introduced into use in the early 1960s and represented a major breakthrough in the development of antirejection therapy, allowing for more widespread and successful use of kidney, heart and liver transplantation. Azathioprine was approved for use in the United States in 1968 and is still widely used in transplantation and in treatment of autoimmune conditions such as Crohn disease, rheumatoid arthritis and autoimmune hepatitis. Azathioprine is available generically and under the brand name of Imuran as tablets of 50, 75 and 100 mg; a parenteral formulation is also available.
Dosage and administration for Azathioprine
The usual dose is 1 to 3 mg per kilogram or 50 to 150 mg daily and it is typically given long term.
Side effects of Azathioprine
Common side effects include nausea, abdominal upset, rash, aphthous ulcers and dose related bone marrow suppression. Long term use of azathioprine is associated with an increased risk for malignancy, including lymphoma and possibly hepatocellular carcinoma.