grapefruit – The Cluster Headache Support Group

Effects of grapefruit juice and smoking on verapamil concentrations in steady state

On: April 1, 2002

Human gut wall cytochrome P450 (CYP)3A4 is inhibited by grapefruit juice (G), whereas smoking increases CYP1A2 activity. Both enzymes contribute to verapamil biotransformation. This study was performed to quantitatively assess the effect of these factors on verapamil pharmacokinetics in steady state. Read More →

Effect of grapefruit juice on pharmacokinetics and pharmacodynamics of verapamil enantiomers in healthy volunteers

By: CHSG Admin

On: December 1, 2000

In: Verapamil

The present study has demonstrated an interaction between verapamil and grapefruit juice, which is likely due to an inhibition of intestinal metabolism resulting in increased oral bioavailability.Read More →