TREATMENT WITH LOW-DOSE METHOTREXATE IN R HEUMATOID-ARTHRITIS - RISK-FACTORS FOR SERIOUS SIDE-EFFECTS

Treatment with low dose methotrexate in rheumatoid arthritis is associ ated with serious side effects in about 5 per cent of cases (respirato ry, haematological or infectious). The goal of a null risk seems unrea listic because of the idiosyncrasy of some of the risks and our poor u nderstanding of others (enzymatic polymorphisms might be operational, and infectious agents could act as co-factors). However, risk can be g reatly reduced by a careful selection of patients. Some contraindicati ons are strict: poor compliance and the possibilities of mistake in th e timing of the administration; pregnancy or desire for pregnancy; tre atment with trimetoprim; haemodialysis; renal insufficiency (clearance < 50 ml/min) (and therefore old age), alcoholism. Others remain relat ive although well established: hypoalbuminaemia, diabetes mellitus, ob esity, past infection with hepatitis virus. Others are dubious: starva tion, macrocytosis, surgical stress, NSAIDs. An extensive large study of side effects is warranted.