Grapefruit-midazolam interaction varies with juice characteristics

(HealthDay)—The interaction between grapefruit juice and midazolam varies based on grapefruit juice-related characteristics such as the amount of furanocoumarin, according to a study published online Aug. 9 in the Journal of Clinical Pharmacology.

Marina Kawaguchi-Suzuki, Pharm.D., Ph.D., from the University of Florida in Gainesville, and colleagues conducted a trial involving 12 healthy volunteers to examine the effect of regular grapefruit juice (RGJ) and a novel, low furanocoumarin hybrid grapefruit juice (HGJ) on the metabolism of oral midazolam, compared with water as a control.

The researchers found that the point estimate for the RGJ/water midazolam area under the curve (AUC) geometric mean ratio was 1.22 percent. The point estimate for the HGJ/water midazolam AUC ratio was within the bioequivalence range of 80 to 125 percent, indicating no interaction. In a systematic review of the evidence of the pharmacokinetic alteration of midazolam by grapefruit juice, most studies showed alteration in midazolam pharmacokinetics, supporting CYP3A activity inhibition as a likely mechanism; however, there was wide variation in the cohorts included and extent of pharmacokinetic interaction.

"The current study indicated grapefruit juice-drug interaction varies substantially based on patient characteristics and/or grapefruit juice product-related factors, including the amount of furanocoumarin constituents present in the juice," the authors write.

One author was an inventor on patent applications for hybrid grapefruit 914.