To investigate the efficacy and safety of Isoniazid prophylaxis (INHP) for tuberculosis in Chinese patients with rheumatoid arthritis (RA) who receive long-term Methotrexate (MTX) therapy.
Two hundred and one (201) patients with RA were randomized to initial treatment with either MTX/Isoniazid (INH) [MTX, 0.1-0.3 mg/(kg x week), maximal 20 mg/week; INH, 5 mg/(kg x d), max 300 mg/d] or MTX alone [0.1-0.3 mg/(kg x week), maximal 20 mg/week]. The doses of MTX remained the same after 6-month INH treatment. All patients were followed up for 36 months, the incidence of pulmonary tuberculosis (TB) was investigated, while the toxicity of INH and MTX were assessed.
There were 77 patients completed INHP. Two withdrew due to unwilling to participate. Treatment was discontinued in 4 cases (4.9%) owing to toxicity: increasing ALT/AST in two (2.5%), decrease of white blood cell (WBC) in one (1.2%) and anaphylaxis in one (1.2%). In control group, 5 patients withdrew for personal reasons. The incidence of adverse effect due to MTX in this group was 6.2%: Hepatotoxicity appeared in 4 patients (3.5%) and decrease of WBC was seen in 3 (2.7%). Nine patients (8.5%) developed TB in control group, and 1 patient (1.3%) developed TB 14 months after INH treatment. The risk of TB infection in control group was 6 times more than that in INHP group (chi2 = 4.47, P < 0.05).
INHP is safe and effective to prevent TB in RA patients treated with MTX.