Dramatic response after an intravenous loading dose of azathioprine in onecase of severe and refractory ankylosing spondylitis

We describe a 37-yr-old Caucasian male suffering from ankylosing spondyliti s (AS) with long standing severs inflammatory lumbar pain and hip arthritis who was refractory to nonsteroidal anti-inflammatory drugs, sulphasalazine and methotrexate up to 25 mg/week. In this patient, administration of an i .v. loading dose of azathioprine (AZA: 40 mg/kg for 36 h Followed by 2 mg/k g oral AZA therapy) induced a dramatic response in his clinical condition. Indeed. objective and subjective clinical variables improved within 1 week and were corroborated by a decline in the levels of the inflammatory parame ters; anaemia was reported at month 3 but was rapidly reversible. If confir med. an i.v. loading dose of AZA could represent a valuable alternative in severe and refractory AS, but toxicity of this regimen should be carefully analysed.