The in vivo and in vitro effect of phenylephrine (neo synephrine) on nasal ciliary beat frequency and mucociliary transport

Abstract

Twenty volunteers with normal noses were studied to determine the effect of phenylephrine on nasal ciliary function. In vivo study of this drug was performed in 15 patients and revealed a significant increase in their ciliary beat frequency from a control of 11 Hz to 12.03 Hz (p = 0.001). Mucociliary transit times in these volunteers were also studied, revealing a mean of 9.9 minutes prestimulation and 10.2 minutes poststimulation, which was not statistically significant (p = 0.77). Five additional subjects donated ciliated mucosal samples for in vitro analysis of varying concentrations of this agent that showed a significant ciliostimulatory effect at lower concentrations (0.01%), with a progressive cilioinhibitory effect at higher concentrations (0.25%, 0.5%). The 0.05% concentration showed no significant change in ciliary activity compared to control measurements. These data demonstrate that phenylephrine has a ciliostimulatory effect in vivo, as well as in appropriate concentrations in vitro, and should be safe and relatively nontoxic to the mucociliary apparatus for short-term use.

Effects of Ephedrine on Human Nasal Ciliary Beat Frequency

“…3 ). Our results are in agreement with effects of a range of concentrations of phenylephrine, from 0.01 to 0.5%, on human nasal CBF [15] . Since both the absolute ( ϳ 1 Hz) and normalized increments ( ϳ 10%) of CBF were relatively small, an accurate quantification of the ciliary activity with high temporal resolution was required to detect the small change in CBF within 1 min.…”

“…Human nasal CBF decreased significantly in cilia that had been incubated in different concentrations of phenylephrine (from 0.125 to 2.5%) for different periods of time (from hours up to 6 days), even at the lowest concentrations of phenylephrine (0.125%) [10] . Other reports indicate that shorter incubation times (60 min) in lower concentrations of phenylephrine (0.01%) cause a stimulatory effect on human nasal CBF, while higher concentrations (0.25 and 0.5%) cause inhibitory effects [15] . It is well known that effects of nasal decongestants on nasal CBF may influence nasal MTT.…”

“…Since MTT has previously been reported to range from less than 3 to less than 20 min, and a normal MTT was about 12-15 min [1] , an observation of instant CBF response within 15 min may mimic the in vivo environment more closely. In this study we used high-speed digital microscopy combined with beatby-beat analysis instead of fast Fourier transform [6,10,15,18] , the more commonly used method for CBF analysis reported in the literature. This latter method requires a multipoint sample and reduces temporal resolution of data.…”

“…The nonselective ␣ , ␤ -adrenoceptor agonist ephedrine also shows inhibitory effects on rat tracheal CBF [14] . Phenylephrine is reported to have a ciliostimulatory effect on human nasal CBF at low concentrations (0.01%) and a cilioinhibitory effect at higher concentrations (0.25 and 0.5%) [15] . In addition, phenylephrine (0.5%) and tetrahydrozoline (0.1%) are reported to have stimulatory effects on human mucus transport time (MTT) [16] , which also indirectly supports a ciliostimulatory effect on CBF.…”

Influence of Intranasal Drugs on Human Nasal Mucociliary Clearance and Ciliary Beat Frequency

“…Moreover, we demonstrated that the clinically used concentration of ephedrine (0.5%) induced the highest stimulatory effect, without any obvious inhibitory effect on human nasal CBF 25. Phillips and colleagues26 investigated the in vivo and in vitro effect of phenylephrine on nasal CBF and mucociliary transport of healthy volunteers and demonstrated that while phenylephrine had a cilio-stimulatory effect in vivo as well as at a low concentration (0.01%) in vitro , it also had a cilio-inhibitory effect at higher concentrations (0.25% and 0.5%) in vitro 26. Similarly, Min and colleagues27 reported that at concentrations of 0.125% to 2.5%, phenylephrine induced a significant decrease in human nasal CBF in a dose-dependent- and time-dependent manner 27…”