The need of mycophenolic acid monitoring in long-term renal transplants.
BACKGROUND
There is little information regarding the 12-h mycophenolic acid (MPA) pharmacokinetics (PK), a way to monitor the drug and the need of frequent monitoring, in stable patients.


METHODS
A cohort of 35 adults, under long-term mycophenolate mofetil (MMF) therapy plus cyclosporin A (n = 12), TACimus (n = 12) or MMF only (n = 11); all with prednisone had a 12-h MPA-PK performed to ascertain the percentage of them within a defined therapeutic window. In 13 other patients, two PK studies undergone 1 wk apart were performed to evaluate the need for frequent measurements.


RESULTS
Fourteen (40%) patients were within the defined therapeutic window (36-60 microg h/mL). Nine patients (26%) were overexposed while 12 (34%) were underexposed. A Cmax> or =10 microg/mL was seen in 20 (57%) of the patients. These percentages were equally distributed between the treatment groups both for AUC0-12 and Cmax. The equations using C0, C2 or both predict exposure, although the use of C2 seems to be more adequate in clinical practice. There were no differences in MPA exposure in patients with a repeated PK evaluated 1 wk later.


CONCLUSIONS
The use of MMF without monitoring MPA blood levels may cause over-/underexposure to the drug in stable recipients. However, in patients under MMF for more than 1 yr, MPA levels are stable and there is no need for frequent measurements.
David-Neto
Elias
E
Renal Transplant Unit, Divisions of Urology and Nephrology, Hospital das Clìnicas, University of São Paulo, School of Medicine, Sao Paulo, Brazil. elias.david.neto@attglobal.net
Pereira
Lilian M
LM
Kakehashi
Erica
E
Sumita
Nairo M
NM
Mendes
Maria E
ME
Castro
Maria Cr
MC
Romano
Paschoalina
P
Mattos
Renata M
RM
Batista
Vania Rm
VR
Nahas
William C
WC
Ianhez
Luiz E
LE
D000328:Adult; D015331:Cohort Studies; D016903:Drug Monitoring; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000276:immunology / Q000627:therapeutic use*; D016030:Kidney Transplantation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000031:analogs & derivatives* / Q000276:immunology / Q000627:therapeutic use*
D007166:Immunosuppressive Agents; D009173:Mycophenolic Acid