Phenylephrine Pharmacokinetics and First-Pass Metabolism: What Is an Ideal Pharmacokinetic Surrogate?

Excerpt

The recently published work on phenylephrine has distinctly showcased the pharmacokinetic disposition of phenylephrine across various single doses following oral administration [1]. Since limited pharmacokinetics of phenylephrine and its metabolite(s) have been published in the literature, the work of Gellote and Zimmerman assumes high importance because it sheds some new light on the first-pass metabolism of phenylephrine via presumably sulfate conjugation [1]. The objectives of this letter are (1) to further provide perspectives on the pharmacokinetic data on phenylephrine, drawing some comparisons with the pharmacokinetic data on other published drugs that undergo a similar kind of first-pass effect and display relatively short half-life values; and (2) to put forward a pharmacokinetic surrogate that may help to establish the significance of first-pass metabolism of not only phenylephrine but also other drugs. …