Intranasally administered phenylephrine and blood pressure

Area of Science:

• Pharmacology
• Cardiovascular Medicine
• Otolaryngology

Background:

• Intranasal phenylephrine is commonly used for nasal congestion.
• Concerns exist regarding potential systemic vasoconstriction and increased blood pressure, especially in at-risk populations.
• Previous studies have not extensively evaluated high doses in hypertensive patients on beta-blockers.

Purpose of the Study:

• To investigate the systemic effects of high-dose intranasal phenylephrine.
• To assess the impact on blood pressure and heart rate in patients with normal blood pressure and hypertension on metoprolol.
• To determine the safety profile of intranasal phenylephrine in these susceptible groups.

Main Methods:

• A double-blind, placebo-controlled study was conducted.
• Two groups were included: patients with normal blood pressure (n=12) and hypertensive patients on metoprolol (n=14).
• Increasing doses of phenylephrine (0.5-4 mg) or placebo were administered intranasally hourly, with vital signs monitored every 10 minutes.

Main Results:

• No significant changes in blood pressure were observed in either group after phenylephrine administration.
• Heart rate remained stable, with no significant alterations noted.
• The total administered doses of phenylephrine were substantially higher than recommended manufacturer doses (4-30 times).

Conclusions:

• Intranasal phenylephrine, even at supra-therapeutic doses, appears safe for individuals with normal blood pressure.
• Hypertensive patients receiving metoprolol did not experience significant adverse cardiovascular effects from high-dose intranasal phenylephrine.
• The study supports the cardiovascular safety of intranasal phenylephrine in at-risk populations when used as directed.