Overview
11 DESCRIPTION Phenylephrine is an alpha-1 adrenergic receptor agonist. Phenylephrine hydrochloride Injection, 10 mg/mL is a clear, colorless, sterile, nonpyrogenic solution for intravenous use. It must be diluted before administration as an intravenous bolus or continuous intravenous infusion.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Phenylephrine hydrochloride is an α-1 adrenergic receptor agonist. 12.2 Pharmacodynamics Interaction of phenylephrine with α1-adrenergic receptors on vascular smooth muscle cells causes activation of the cells and results in vasoconstriction. Following phenylephrine hydrochloride intravenous administration, increases in systolic and diastolic blood pressures, mean arterial blood pressure, and total peripheral vascular resistance are observed. The onset of blood pressure increase following an intravenous bolus phenylephrine hydrochloride administration is rapid, typically within minutes. As blood pressure increases following intravenous administration, vagal activity also increases, resulting in reflex bradycardia.
Indications
- 1 INDICATIONS & USAGE Phenylephrine hydrochloride Injection, 10 mg/mL is indicated for the treatment of clinically important hypotension resulting primarily from vasodilation in the setting of anesthesia. Phenylephrine hydrochloride Injection is an alpha-1 adrenergic receptor agonist indicated for the treatment of clinically important hypotension resulting primarily from vasodilation in the setting of anesthesia.
Common Doses
- 10 mg
- 40 mcg
- 100 mcg
- 200 mcg
Dosage
2 DOSAGE & ADMINISTRATION Phenylephrine hydrochloride Injection, 10 mg/mL, is injected intravenously either as a bolus or in a dilute solution as a continuous infusion. Dilute before administration. ( 2 ) Dosing for treatment of hypotension during anesthesia Bolus intravenous injection: 40 mcg to 100 mcg every 1 to 2 minutes as needed, not to exceed 200 mcg. (2) Intravenous infusion: 10 mcg/min to 35 mcg/min, titrating to effect, not to exceed 200 mcg/min. (2) Adjust the dose according to the pressor response (i.e., titrate to effect). (2) 2.
Contraindications
- 4 CONTRAINDICATIONS None None
Side Effects
- 6 ADVERSE REACTIONS Adverse reactions to Phenylephrine hydrochloride injection are primarily attributable to excessive pharmacologic activity. Adverse reactions reported in published clinical studies, observational trials, and case reports of Phenylephrine hydrochloride injection are listed below by body system. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency reliably or to establish a causal relationship to drug exposure.
Interactions
- 7 DRUG INTERACTIONS Agonistic effects (increase in Phenylephrine hydrochloride injection blood pressure effect) can occur with monoamine oxidase inhibitors (MAOI), oxytocin and oxytocic drugs, tricyclic antidepressants, angiotensin and aldosterone, atropine, steroids, norepinephrine transporter inhibitors, ergot alkaloids ( 7.1 ) Antagonistic effects (decrease in Phenylephrine hydrochloride injection blood pressure effect) can occur with α-adrenergic antagonists, phosphodiesterase Type 5 inhibitors, mixed α- and β-receptor antagonists, calcium channel blockers, benzodiazepines and ACE...