To review systematically the available literature on the optimal dosage and route of administration of methotrexate in patients with rheumatoid arthritis (RA), as an evidence base for generating clinical practice recommendations.
A systematic literature search was carried out in MEDLINE, EMBASE, Cochrane Library and American College of Rheumatology/European League Against Rheumatism meeting abstracts, searching for randomised controlled trials evaluating various dosages or routes of administration of methotrexate in RA. Articles that fulfilled predefined inclusion criteria were systematically reviewed and the quality was appraised. Effect sizes and odds ratios for clinical, radiological and toxicity outcomes were calculated and directly or indirectly compared between study groups using methotrexate in different dosages or by different routes.
A total of 38 publications out of 1748 identified references was included in the review. Start doses of 25 mg/week or fast escalation with 5 mg/month to 25-30 mg/week were associated with higher clinical effect sizes and more (gastrointestinal) adverse events in comparison with doses of 5-15 mg/week or slow escalation. Starting with 15 mg/week subcutaneous versus oral methotrexate was associated with higher clinical efficacy but more withdrawal due to toxicity in early RA. In longstanding RA, after failure on 15-20 mg/week orally, a switch to 15 mg/week intramuscularly with subsequent dose escalation did not result in increased efficacy.
Starting on methotrexate 15 mg/week orally, escalating with 5 mg/month to 25-30 mg/week, or the highest tolerable dose, with a subsequent switch to subcutaneous administration in the case of an insufficient response, seems to be the optimal evidence-based dosing and routing recommendation for methotrexate in RA.