Renal effects of low dose methotrexate in rheumatoid arthritis.
OBJECTIVE
Methotrexate (MTX) treatment at high doses may cause renal failure. The effects of treatment with low MTX doses on kidney function are, however, unknown. The objective of our study was to investigate the effect of low MTX doses on kidney function.


METHODS
The glomerular filtration rate was measured as the plasma clearance of 51Cr-EDTA and the clearance of 99mTc-dimercaptoacetyl-triglycine (correction of triglycerine) (99mTc-MAG3), a new renal tubular function agent, was used to measure tubular effects of MTX.


RESULTS
Significant decrease of both 51Cr-EDTA clearance from 92 +/- 7 to 83 +/- 5 ml/min x 1.73 m2 (mean +/- SEM) and of the 99mTc-MAG3 clearance from 360 +/- 18 to 309 +/- 15 ml/min x 1.73 m2 (p < 0.05) was observed.


CONCLUSIONS
Our results indicate that low dose MTX treatment (15 mg weekly) may significantly impair kidney function which has to be considered particularly in situations with combined treatment with other potentially nephrotoxic substances.
Department of Internal Medicine, Karolinska Institute, Danderyd Hospital, Sweden.
P
P
Seideman
R
R
Müller-Suur
E
E
Ekman
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000503:physiopathology; D002860:Chromium Radioisotopes; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000493:pharmacokinetics; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D007674:Kidney Diseases / Q000139:chemically induced / Q000503:physiopathology; D007678:Kidney Glomerulus / Q000187:drug effects / Q000502:physiology; D007684:Kidney Tubules / Q000187:drug effects / Q000502:physiology; D008297:Male; D008657:Metabolic Clearance Rate; D008727:Methotrexate / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D017263:Technetium Tc 99m Mertiatide / Q000493:pharmacokinetics
D002860:Chromium Radioisotopes; D017263:Technetium Tc 99m Mertiatide; D004492:Edetic Acid; D008727:Methotrexate