Effect of food on the bioavailability of oxybutynin from a controlled release tablet.

OBJECTIVE: The effect of food on the bioavailability of oxybutynin was assessed in a randomised cross-over study in 23 healthy volunteers. A single oral 10 mg dose of a controlled release oxybutynin tablet was administered after a high fat breakfast and to fasting subjects. The AUC, Cmax, tmax, t1/2 and MRT of oxybutynin and its active metabolite N-desethyloxybutynin were determined.
RESULTS: Breakfast did not change the AUC of oxybutynin but increased the AUC of N-desethyloxybutynin by about 20%. The Cmax of oxybutynin and N-desethyloxybutynin were two-fold higher when the drug was administered after breakfast compared to the fasting state.
CONCLUSION: Breakfast significantly reduced the MRT of oxybutynin and N-desethyloxybutynin.

RCT Entities:   Population Interventions Outcomes