Adverse reactions to disease-modifying anti-rheumatic drugs in clinical practice

We analysed computerized records of disease-modifying anti-rheumatic drug ( DMARD) monotherapy to determine how long rheumatoid arthritis (RA) patients continued on five commonly prescribed DMARDs, and the incidence and timeco urse of adverse drug reactions (ADRs) they experienced, We studied the reco rds for 3923 courses of DMARDs given to a cohort of 2170 patients monitored for a total of 9378 treatment-years. Methotrexate (MTX) was the DMARD most likely to be continued long-term; < 45% of patients had discontinued the d rug after 96 months. For the other DMARDs, the time until 50% discontinued due to ADRs or inefficacy was 43.3 months for sulphasalazine (SAS), 33.9 mo nths for D-penicillamine (DPN) and 26 months for myocrisin. Most monitored ADRs requiring drug discontinuation were seen early in therapy, with a medi an time to onset of < 6 months; the important exceptions to this were haema tological ADRs to MTX, where the median delay to neutropenia was 16.9 month s, and that to thrombocytopenia was 9.4 months. Monitored ADRs (identified by blood or urine tests) were seen least frequently with SAS (one ADR in ev ery 35 patient-years of monitoring) but this apparent advantage was offset by a high incidence of gastrointestinal ADRs and inefficacy. Overall, one t oxicity reaction requiring drug discontinuation was identified for every 15 .9 patient-years of monitoring.