How Long Does Grapefruit Juice Inhibit CYP3A4?

By inhibiting intestinal CYP3A4 activity, grapefruit juice increases the maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC) of oral . . .

By inhibiting intestinal CYP3A4 activity, grapefruit juice increases the maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC) of oral (but not parenteral) CYP3A4 substrates such as midazolam, triazolam, diazepam, dihydropyridine calcium-channel blockers, buspirone, and carbamazepine (see JW Psych July 1999, p. 60). After examining the interaction between grapefruit juice and the calcium-channel blocker nisoldipine (which is metabolized by 3A4) in 8 healthy volunteers, this Japanese crossover study reported that increased activity of this substance persists long after a person stops drinking grapefruit juice.

Participants took nisoldipine in 6 doses: 10 mg with water, 5 mg with grapefruit juice, or 5 mg…

Reviewing Author

S Dubovsky