Safety and efficacy of azathioprine as a second line therapy for primary immune thrombocytopenic purpura

Abstract

Introduction: Immune thrombocytopenic purpura remains common blood disease in Nepal. Azathioprine is an oral immunosupressive medicine which has been used widely in various autoimmune disease and solid organ transplant patients. It is inexpensive, easily available and well tolerated medicine. This study was carried out to evaluate efficacy and safety of azathioprine as a second line medicine for primary ITP patients who were refractory to steroid therapy. Methods: The observational, pre-post study was conducted at Government of Nepal Civil Service Hospital, Kathmandu from January to October 2014. Twenty four primary ITP patients who were steroid refractory were treated with Azathioprine. Patients were termed steroid refractory if platelet counts were less than 30,000/ul on day 21st of steroid therapy. From day 22 onwards oral azathioprine 2mg/kg was started and steroids were tapered 10mg/week and stopped. Platelet counts of more than 30000/ul after one month of stopping steroid, while still on azathioprine, were termed response to azathioprine. Platelet count of more than 100,000/ul was termed complete response. The associations among age, gender, duration and platelets counts were analyzed by chi square test and Fisher's exact test (when individual cell frequency was less than 5). The comparison of platelets counts among the start and day 90 of Azathioprine therapy was performed by the paired t-test. Results: The study showed that there was not significant association among age and gender of the patients and their platelets count on the start of Azathioprine therapy (p value 0.354 and 0.725 respectively) and on day 90 of Azathioprine therapy (p value 0.082 and 0.762 respectively). The duration-wise comparisons of platelets count on both the start and day 90 of Azathioprine therapy were significant (p values 0.029 and 0.008 respectively). The paired comparison among platelets count on the start and day 90 of Azathioprine therapy was highly significant (p value 0.000). Conclusions: The study showed the therapeutic implication of azathioprine in ITP patients. It also showed that efficacy of azathioprine was comparable with other modes of treatment. In low income countries like Nepal azathioprine can be considered as second line treatment for steroid refractory ITP patients.