Azathioprine

Azathioprine is an immunosuppressive antimetabolite. Imidazolyl derivative of 6- mercaptopurine. Widely used due to its immunosuppresant and anti-inflammatory properties Interferes with nucleic acid synthesis ( Purine antagonist ) Used either alone or in combination ( usually corticosteroids) Azathioprine is a pro-drug- rapidly converted to 6-MP which is then metabolized by purine salvage pathway It may take weeks to months for significant response to be achieved Usually started @ 50 mg/ day ( available in 25 ,50 , 100 mg )Typical maintenance dose may be 2 to 2.5 mg/kg

Indications- Following organ transplant Reduce steroid requirement of renal transplant patients Psoariatic arthritis Severe rheumatoid arthritis SLE Dermatomyositis Polymyositis Autoimmune chronic active hepatitis Pemphigus vulgaris Polyarteritis nodosa Auto-immune haemolytic anaemia Chronic idiopathic thrombocytopenic purpura

Adverse effects- NauseaDose-dependentUsually resolves after few weeksGradual dose escalation may helpDivided daily doseAntiemetics HypersensitivityIdiosyncratic immunologically mediated reactionCan present with a distinct symptoms within few weeksGeneralised or organ specific symptoms as○ fever○ myalgia○ arthralgia○ nausea

MyelotoxicityBone marrow suppression --> NeutropeniaDose dependentCan be seen in up to 5-30 % Susceptibility to infectionEven in absence of neutropeniaMild lymphopenia may contribute to thisVZV ( Varicell zoster ) is particularly seen more commonly HepatotoxicityMild derangement common- usually with no serious complicationTwo patterns of...