Is weekly azathioprine pulse effective and safe in dermatological conditions?

Azathioprine, a purine synthesis inhibitor is widely used as an effective immunosuppressant in several immune mediated diseases, usually in a dose of 2 to 2.5 mg/kg per day. The pulse dose of azathioprine is an unique once weekly dosing regimen, which has been used as an alternative to daily dose regimen in some immune mediated dermatologic disorders. In this review, we looked at a specific dosing regimen, "weekly azathioprine pulse" with respect to its efficacy and safety in the treatment of dermatologic diseases. We performed a literature search for studies on azathioprine weekly pulse in dermatology in various scientific databases using keywords "azathioprine-pulse", "dermatology", "weekly azathioprine", and so on. Dosing regimens, indications, efficacy, monitoring, and side effect profile as described in these studies were recorded. Evidence level of the regimens used in various indications was also calculated. We could find six published studies using azathioprine weekly pulse, of which three were randomized comparative clinical trials. Azathioprine pulse was administered in a dose of 300 mg (6 tablets of 50 mg each) every week in all the studies. It has been found to be effective in management of contact dermatitis due to parthenium (IB), chronic plaque psoriasis (IIB), and alopecia areata (IB). Adverse effect profile was found to be almost similar to daily azathioprine. Weekly azathioprine pulse, therefore, appears to be an effective and safe alternative to daily azathioprine in the management of immune mediated disorders in dermatology. Although studies are limited, this regimen seems promising and further studies are warranted.