Background Methotrexate has been recognised as one of the main therapeutic agents used in rheumatoid arthritis (RA). However some of the adverse effects of low-dose methotrexate therapy and in particular pancytopenia have caused major concern.

Objectives The aim was to describe our experience of long-term follow up of patients with RA treated with low-dose methotrexate, in particular in reference to the appearance of pancytopenia.

Methods During the last 14 years 528 RA patients were treated with methotrexate 7.5–15 mg/week by the Rheumatology Department. These patients were followed up by the Rheumatology Department and they had a complete laboratory evaluation and clinical examination in regular intervals.

Results In 528 RA patients treated with low-dose methotrexate therapy over a period of 14 years 4 cases of aplastic anaemia were diagnosed (0.76%). In these patients the white cell count, platelet count, haemoglobin and haematocrit values decreased. In all 4 cases liver function tests were slightly elevated. Folinic calcium was administered and white cell and platelet counts improved, while haematocrit remained stable. The increase in white cell count after the administration of folinic calcium was satisfactory and the addition of growth factors to aid haemopoiesis was not considered necessary. In a female patient a very marked decrease in white cell count was observed and the patient died from sepsis, despite the administration of antibiotics.

Conclusion Low-dose methotrexate therapy in long term follow-up appears to be a safe and effective form of therapy for RA patients. Therapy appears to be well tolerated by the patients. Pancytopenia appears to be one of the most significant and dangerous complications of this form of therapy, being observed even in the absence of other recognised risk factors. Pancytopenia may occur abruptly in patients with RA on low-dose methotrexate therapy. Regular laboratory investigations are essential for the early detection of this complication. The administration of supplement folate in patients with RA on low-dose methotrexate therapy may reduce the incidence of pancytopenia.