['Reactivation of Mycobacterium tuberculosis (TB) is a significant problem with all available tumour necrosis factor (TNF) antagonists when used to treat rheumatoid arthritis (RA), psoriatic arthritis, psoriasis and other inflammatory diseases. Concerns have been raised regarding the appropriate management of patients with latent TB (LTB) exposure (or active TB infection) before initiating TNF antagonists as the safety data of combined treatment with two potentially hepatotoxic medications, methotrexate (MTX) and isoniazid (INH), is lacking. The goal of this study was to investigate the toxicity of MTX and INH treatment in patients with RA before initiating TNF antagonists.', 'To investigate the toxicity of MTX and INH treatment in patients with RA we performed a retrospective chart review of patients seen at the Bellevue Hospital Arthritis Clinic in New York City between 2002 and 2006. Forty-four patients who were concomitantly treated with both drugs were included. The primary outcome investigated was increase in liver function tests (LFT).', 'Transient increases in LFT were seen in 11% of patients, but in no case was this more than twice the upper limit of normal values. All abnormal LFT resolved spontaneously without intervention. In addition, no patient has developed signs or symptoms of TB reactivation.'] Is methotrexate combined with isoniazid treatment for latent tuberculosis well tolerated in patients with rheumatoid arthritis : experience from an urban arthritis clinic?