Comparison of inosine-monophosphate-dehydrogenase activity in patients with enteric-coated mycophenolate sodium or mycophenolate mofetil after renal transplantation.
BACKGROUND
Mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS) are well established in immunosuppressive therapy after renal transplantation. The active substance, mycophenolic acid, leads to an inhibition of inosine-monophosphate-dehydrogenase (IMPDH) activity in peripheral mononuclear cells. Therefore, we analyzed the effect of different dosing patterns of MMF and EC-MPS on IMPDH activity in stable patients after renal transplantation.


METHODS
IMPDH activity (pmol/s per pmol AMP) was measured in patients in the maintenance phase after renal transplantation. Besides MMF or EC-MPS, immunosuppressive therapy consisted of calcineurin inhibitor with or without steroids. We performed 260 measurements in 110 patients (82 on MMF, and 28 on EC-MPS).


RESULTS
Mean patient age range of 43 women and 67 men was 22 to 74 years. Mean serum creatinine in the MMF group was 1.7 +/- 1.3 mg/dL compared to 1.48 +/- 0.45 mg/dL in the EC-MPS group (P < .05). The median IMPDH activity in the EC-MPS patients was lower than in the MMF patients (10 vs 24 pmol/s pmol AMP; P < .005). This was especially pronounced in patients on 1440 mg/d EC-MPS compared with 2000 mg/d MMF (P < .001).


CONCLUSIONS
Measurement of IMPDH activity in renal transplantation patients adds additional information on the degree of immunosuppression. The inhibition of IMPDH activity with EC-MPS seemed more pronounced than MMF despite formally equipotent doses.
Rath
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T
Department of Nephrology and Transplantation Medicine, Medical Clinics III, Westpfalz-Klinikum, Kaiserslautern, Germany. trath@westpfalz-klinikum.de
Küpper
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D000328:Adult; D000368:Aged; D016572:Cyclosporine / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007168:IMP Dehydrogenase / Q000097:blood* / Q000187:drug effects; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000276:immunology* / Q000502:physiology; D007963:Leukocytes, Mononuclear / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D013608:Tablets, Enteric-Coated; D016559:Tacrolimus / Q000627:therapeutic use; D055815:Young Adult
D007166:Immunosuppressive Agents; D013608:Tablets, Enteric-Coated; D016572:Cyclosporine; D007168:IMP Dehydrogenase; D009173:Mycophenolic Acid; D016559:Tacrolimus