Formulation of diltiazem affects cyclosporin-sparing activity.
OBJECTIVE
To consider the effect of changing from a conventional release formulation of diltiazem to the controlled diffusion diltiazem formulation on the cyclosporin-sparing effect in kidney transplant recipients.


METHODS
Seven stable renal transplant recipients were studied on two separate occasions following at least 2 weeks stabilisation on either formulation. The order of administration of the two formulations was not randomised as all patients were already prescribed lower dosages of diltiazem before entering this phase of a larger study. The doses of diltiazem used were 90 mg (conventional release diltiazem) taken twice daily and 180 mg controlled diffusion diltiazem taken in the morning.


RESULTS
Whilst there were no overall significant differences between the two formulations, the study demonstrated considerable interpatient variability when changing to the controlled diffusion formulation, particularly following the morning cyclosporin dose, with three patients showing a reduced cyclosporin AUC (30-60%) and one an increased cyclosporin AUC of 36%.


CONCLUSIONS
A change in formulation of the cyclosporin-sparing agent may result in unpredictable alterations in cyclosporin concentrations and resultant clinical sequelae.
Jones
T E
TE
Department of Pharmacy, Queen Elizabeth Hospital, Woodville, Australia.
Morris
R G
RG
Mathew
T H
TH
D000328:Adult; D000959:Antihypertensive Agents / Q000009:adverse effects*; D002648:Child; D016572:Cyclosporine / Q000037:antagonists & inhibitors*; D003692:Delayed-Action Preparations; D004058:Diffusion; D004110:Diltiazem / Q000008:administration & dosage / Q000009:adverse effects*; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000037:antagonists & inhibitors*; D016030:Kidney Transplantation / Q000276:immunology*; D008297:Male; D008875:Middle Aged
D000959:Antihypertensive Agents; D003692:Delayed-Action Preparations; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D004110:Diltiazem