Are there any situations in which phenylephrine is preferred to pseudoephedrine?

Question

In the mid 2000s in the US, due to issues of drug enforcement, pseudoephedrine containing medications were brought behind the pharmacy counter and in most cases require ID, and phenylephrine was substituted in most over-the-counter products.Pseudoephedrine increases the amount of endogenous norepinephrine, whereas phenylephrine works on α1-adrenergic receptors directly.There are numerous cases where experts have spoken out about the effectiveness of phenylephrine, so it likely is a less effective substitute for pseudoephedrine in its main role as a decongestant.What I'm curious about is whether there are clinical indications for which the phenylephrine is actually preferred (so situations where the α1-agonist nature without the increase of endogenous NE is sought after)?

Answer 1

The half life of phenylephrine is about half (2-3 hours) that of pseudoephedrine (5-6 hours). In a scenario where you'd be using either drug as a decongestant, the agent containing phenylephrine is obviously going to last a bit shorter, thus requiring more frequent dosing.

In a scenario trying to control something like, say, hypotension, phenylephrine may be preferable over another agent due to its quick-onset and relative ease in ability to titrate to effect.