Azathioprine Pharmachemie Dosage/Direction for Use

Specialist medical literature should be consulted for guidance as to clinical experience in particular conditions.
Dosage: Adults: With transplantations: Depending on the immunosuppressive regimen employed, a dosage of 3-5 mg/kg of body weight per day, one to three days before or at the time of surgery.
Maintenance dosage should range from 1-3 mg/kg of body weight per day and must be adjusted according to clinical requirements and haematological tolerance.
Evidence indicates that Azathioprine therapy should be maintained indefinitely, even if only low doses are necessary, because of the risk of graft rejection.
Rheumatoid arthritis: Usually given daily. Initial dose is approximately 1 mg/kg (50 to 100 mg) given as a single dose or twice daily. The dose may be increased, beginning at 6 to weeks and thereafter by steps at 4 week intervals, if there are no serious toxicities and initial response is unsatisfactory. Use dose increments of 0.5 mg/kg/day up to a maximum dose of 2.5 mg/kg/day.
Therapeutic response occurs after 6 to 8 weeks of treatment; an adequate trial should be a minimum of 12 weeks. Patients not improved after 12 weeks are refractory. Continue the drug in patients with clinical response, but monitor carefully, and attempt gradual dosage reduction to reduce risk of toxicity. Optimum duration of therapy has not been determined. Use the lowest effective dose for maintenance therapy; lower decremental with changes of 0.5 mg/kg or approximately 25 mg/day every 4 weeks while other therapy is kept constant. Azathioprine can be discontinued abruptly, but delayed effects are possible.
Children: With transplantation and other indications: See Adults as previously mentioned.
Elderly: There is limited experience of the administration of Azathioprine to elderly patients. Although the available data do not provide evidence that the incidence of side effects among elderly patients is higher than that among other patients treated with Azathioprine, it is recommended that the dosages used should be at the lower end of the range.
Particular care should be taken to monitor haematological response and to reduce the maintenance dosage to the minimum required for clinical response.
Renal or Hepatic Impairment: In patients, dosage should be given at the lower end of the normal range (see Precautions).