Detailed Drug Information:

DRUG CLASS: Azathioprine is classified as an immunosuppressantmedication. Azathioprine is used to suppress the immune system in patientswho have had kidney transplants. Although its exact mechanism of action inrheumatoid arthritis is not known, its effect in suppressing the immunesystem appears to decrease the activity of this illness.

PREPARATIONS: Tablet: 50mg; It can also be given intravenously.

STORAGE: Store at 59 to 77degrees F, in a sealed,light-resistant, container, avoid moisture.

PRESCRIBED FOR: Azathioprine is used to inhibit the immuneresponse that causes rejection of kidney transplants. Azathioprine is alsoused for the treatment of severe, active rheumatoid arthritis. It isconsidered a "second-line," or "slow-acting" drug andis usually reserved for rheumatoid arthritis patients who do not respondto other first-line or second-line medications.

DOSING: Should be taken with food.

DRUG INTERACTIONS: Azathioprine can cause an increase in cancer risk when used long-term. This particular risk increases in patients witha prior history of treatment with other powerful immunosuppressants, suchas Cytoxan, Leukeran, and Alkeran. It also increases the risk of seriousinfections. Azathioprine can impair fertility by reducing sperm counts inmales. Because azathioprine's toxicity increases when taken with the goutmedication allopurinol (Zyloprim), its dose is reduced with simultaneoususe. Severely low white blood counts can occur when taken with other drugsthat can affect the bone marrow or with ACE-inhibitor class drugs used totreat elevated blood pressure, such as Accupril and Vasotec. The safetyand effectiveness for use in children has not been established.

PREGNANCY: Azathioprine is transferred to the fetus and isavoided in pregnancy.

NURSING MOTHERS: It is also found in breast milk and is not usedin nursing mothers.

SIDE EFFECTS: The most common serious side effects ofazathioprine involve the blood elements and gastrointestinal system.Azathioprine can cause serious lowering of the white blood cell count,resulting in an increased risk of infections. This can reverse when thedose is reduced or temporarily discontinued. Azathioprine can causenausea, vomiting, and loss of appetite, which can resolve when the dose isreduced or divided through the day. Azathioprine can also cause livertoxicity (in less than 1% of rheumatoid arthritis patients). All patientstaking azathioprine require regular blood testing for blood counts andliver function tests for monitoring. Other side effects encountered lessfrequently include fatigue, hair loss, joint pains, and diarrhea.