Response by authors

Kaushal K Verma, Arika Bansal, G Sethuraman

 Department of Dermatology & Venereology, All India Institute of Medical Sciences, New Delhi - 110 029, India

Correspondence Address:
Kaushal K Verma
Department of Dermatology & Venereology, All India Institute of Medical Sciences, New Delhi - 110 029
India

Sir,

We greatly appreciate your interest in our article.[1] The study by Sayani et al . (2005) has shown that there is no correlation between the TPMT activity and the development of azathioprine induced adverse events.[2] Therefore estimation of TPMT levels to predict adverse events seems unnecessary. The apprehension of using 300 mg pulse doses of azathioprine in the absence of TPMT assessment also seems misplaced. There may be some other factors responsible for myelosuppression; therefore regular monitoring of complete blood cell counts throughout the treatment is essential.[3] We have used azathioprine in a large number of patients for prolonged durations and found it clinically and biochemically safe.[4] Pulse doses of azathioprine, administered as 300 mg in a month along with daily doses of azathioprine have also been found to be safe and effective.[5] Therefore 300 mg weekly pulse doses of azathioprine can be safely used. However we recommend close regular monitoring of laboratory parameters, particularly complete blood counts and liver function tests to determine any azathioprine induced adverse events.

1.	Verma KK, Bansal A, Sethuraman G. Parthenium dermatitis treated with azathioprine weekly pulse doses. Indian J Dermatol Venereol Leprol 2006; 72: 24-7 [Google Scholar]
2.	Sayani FA, Prosser C, Bailey RJ, Jacobs P, Fedorak RN. Thiopurine methyltransferase enzyme activity determination before treatment of inflammatory bowel disease with azathioprine: effect on cost and adverse events. Can J gastroenterol 2005;19:147-51. [Google Scholar]
3.	Lennard L. TPMT in the treatment of Crohn's disease with azathioprine. Gut 2002;51:143-6. [Google Scholar]
4.	Verma KK, Manchanda Y. Long -term safety and toxicity of azathioprine in patients with air-borne contact dermatitis. Indian J Dermatol Venereol Leprol 2001;67:75-7. [Google Scholar]
5.	Verma KK, Manchanda Y, Pasricha JS. Azathioprine as a corticosteroid sparing agent for treatment of dermatitis caused by Parthenium. Acta Derm Venereol 2000;80:31-2. [Google Scholar]