PHENYLEPHRINE HYDROCHLORIDE

Phenylephrine is an alpha-1 adrenergic receptor agonist. The chemical name of phenylephrine hydrochloride is (-)- m -hydroxy-α-[(methylamino) methyl] benzyl alcohol hydrochloride, its molecular formula is C 9 H 13 NO 2 · HCl (Molecular Weight: 203.67 g/mol) and its structural formula is depicted below: Phenylephrine hydrochloride is soluble in water and ethanol, and insoluble in chloroform and ethyl ether. Phenylephrine hydrochloride injection, 500 mcg/5 mL (100 mcg/mL): Phenylephrine hydrochloride injection, 500 mcg/5 mL (100 mcg/mL), is a sterile, nonpyrogenic, clear and colorless solution for intravenous use. It MUST NOT BE DILUTED before administration as an intravenous bolus. Each mL contains: phenylephrine hydrochloride 100 mcg (equivalent to 80 mcg of phenylephrine base), sodium chloride 9.0 mg, in water for injection. The pH is adjusted with hydrochloric acid if necessary. The pH range is 3.0 to 5.0. Image

Phenylephrine hydrochloride injection 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.( 1 )

Phenylephrine hydrochloride injection 500 mcg/5 mL (100 mcg/mL) MUST NOT BE DILUTED before administration as an intravenous bolus. It is supplied as a READY-TO-USE formulation. Dosing for treatment of hypotension during anesthesia Bolus intravenous injection: Initial dose is 40 mcg to 100 mcg. Additional boluses up to 200 mcg may be administered every 1 to 2 minutes as needed. Adjust the dose according to the pressor response (i.e., titrate to effect). 2.1 General Dosage and Administration Instructions During Phenylephrine Hydrochloride Injection administration: Correct intravascular volume depletion. Correct acidosis. Acidosis may reduce the effectiveness of phenylephrine. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration. Do not use if the solution is colored or cloudy, or if it contains particulate matter. Discard any unused portion. Administration Instructions for Phenylephrine Hydrochloride Injection, 500 mcg/5 mL (100 mcg/mL): Phenylephrine Hydrochloride Injection, 500 mcg/5 mL (100 mcg/mL) MUST NOT BE DILUTED before administration as an intravenous bolus. It is supplied as READY-TO-USE formulation. 2.2 Dosing for Treatment of Hypotension during Anesthesia The following are the recommended dosages for the treatment of hypotension during anesthesia. Phenylephrine Hydrochloride Injection, 500 mcg/5 mL (100 mcg/mL): The recommended initial dose is 40 to 100 mcg administered by intravenous bolus. Additional boluses may be administered every 1-2 minutes as needed; not to exceed a total dosage of 200 mcg. Adjust dosage according to the blood pressure goal.

None ( 4 ) None ( 4 )

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. Cardiac disorders : Reflex bradycardia, lowered cardiac output, ischemia, hypertension, arrhythmias Gastrointestinal disorders : Epigastric pain, vomiting, nausea Nervous system disorders : Headache, blurred vision, neck pain, tremors Vascular disorders : Hypertensive crisis Respiratory, Thoracic and Mediastinal Disorders : Dyspnea Skin and subcutaneous tissue disorders : Pruritis Most common adverse reactions during treatment: nausea, vomiting, and headache. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Somerset Therapeutics, LLC at 1-800-417-9175 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

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 inhibitors, centrally acting sympatholytic agents. ( 7.2 ) 7.1 Interactions that Augment the Pressor Effect The increasing blood pressure effect of phenylephrine hydrochloride injection is increased in patients receiving: Monoamine oxidase inhibitors (MAOI) Oxytocin and oxytocic drugs Tricyclic antidepressants Angiotensin, aldosterone Atropine Steroids, such as hydrocortisone Norepinephrine transporter inhibitors, such as atomoxetine Ergot alkaloids, such as methylergonovine maleate 7.2 Interactions that Antagonize the Pressor Effect The increasing blood pressure effect of phenylephrine hydrochloride injection is decreased in patients receiving: α-adrenergic antagonists Phosphodiesterase Type 5 inhibitors Mixed α-and β-receptor antagonists Calcium channel blockers, such as nifedipine Benzodiazepines ACE inhibitors Centrally acting sympatholytic agents, such as reserpine, guanfacine