Azathioprine Dosing: An Introduction
The dose of azathioprine
) your healthcare provider recommends will vary, depending on a number of factors, including:
- The medical condition being treated
- How your body responds to azathioprine (some people do not clear the drug from the body as well as others)
- Your weight
- Other medical conditions you may have
- Other medications you may be currently taking.
As is always the case, do not adjust your dose unless your healthcare provider specifically instructs you to do so. People with poor kidney function may need lower azathioprine dosages. Also, a test can be done to see if you have low levels of thiopurine S-methyl transferase (TSMT), an enzyme that helps clear the drug from the body. If you have low TSMT levels, you will need a lower dose (or a different medication altogether) in order to prevent serious side effects.
What Is the Dose for Kidney Transplantation?
The recommended starting dose of azathioprine for preventing kidney transplant rejection is azathioprine 3 mg to 5 mg per kg (about 1.4 mg to 2.3 mg per pound) once daily, starting the day of (or sometimes a few days before) the transplant. Your healthcare provider may decrease your dose to 1 mg to 3 mg per kg (about 0.45 mg to 1.4 mg per pound) once daily if you are doing well.
What Is the Dose for Rheumatoid Arthritis?
The recommended starting dose for rheumatoid arthritis treatment
is azathioprine 1 mg per kg (about 0.45 mg per pound) per day, usually between 50 mg to 100 mg per day. It can be taken once daily or split up into two doses per day. After eight weeks, your healthcare provider may increase your azathioprine dosage, if necessary.