The literature indicates low intraindividual variability in clearance of midazolam, the standard CYP3A probe drug, while absolute bioavailability has not yet been determined.

This is the first study to describe intraindividual variability in absolute bioavailability of midazolam in healthy volunteers.

On average, there was a low to moderate intraindividual variability in systemic clearance and absolute bioavailability of midazolam in healthy individuals over a 2-month period. However, a relevant number displayed considerable intraindividual variability, which may limit the use of midazolam as a probe drug for CYP3A in certain studies.