Phenylephrine Hci for Low Blood Pressure

INDICATIONS & USAGE Phenylephrine Hydrochloride is an alpha-1 adrenergic receptor agonist indicated for increasing blood pressure in adults with clinically important hypotension resulting primarily from vasodilation, in such settings as septic shock or anesthesia.

DOSAGE & ADMINISTRATION 2.1 General Administration Instructions Phenylephrine hydrochloride must be diluted before administration as bolus intravenous infusion or continuous intravenous infusion. Inspect the solution for particulate matter and discoloration prior to administration. The diluted solution should not be held for more than 4 hours at room temperature or for more than 24 hours under refrigerated conditions. Discard any unused portion. During phenylephrine hydrochloride administration: Correct intravascular volume depletion. Correct acidosis. Acidosis may reduce the effectiveness of phenylephrine. 2.2 Preparing a 100 mcg/mL Solution of Bolus Intravenous Administration For bolus intravenous administration, withdraw 10 mg (1 mL of a 10 mg/mL concentration) of phenylephrine injection and dilute with 99 mL of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP. This will yield a final concentration of 100 mcg/mL. Withdraw an appropriate dose from the 100 mcg/mL solution prior to bolus intravenous administration. 2.3 Preparing a Solution for Continuous Intravenous Infusion For continuous intravenous infusion, withdraw 10 mg (1 mL of 10 mg/mL concentration) of phenylephrine hydrochloride injection and add to 500 mL of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP (providing a final concentration of 20 mcg/mL). 2.4 Dosing for Perioperative Setting In adult patients undergoing surgical procedures with either neuraxial anesthesia or general anesthesia: 50 mcg to 250 mcg by intravenous bolus administration. The most frequently reported initial bolus dose is 50 mcg or 100 mcg. 0.5 mcg/kg/min to 1.4 mcg/kg/min by intravenous continuous infusion, titrated to blood pressure goal. 2.5 Dosing for Septic or Other Vasodilatory Shock In adult patients with septic or other vasodilatory shock: No bolus. 0.5 mcg/kg/min to 6 mcg/kg/min by intravenous continuous infusion, titrated to blood pressure goal. Doses above 6 mcg/kg/min do not show significant incremental increase in blood pressure.

WARNINGS AND PRECAUTIONS 5.1 Exacerbation of Angina, Heart Failure, or Pulmonary Arterial Hypertension Because of its pressor effects, phenylephrine hydrochloride can precipitate angina in patients with severe arteriosclerosis or history of angina, exacerbate underlying heart failure, and increase pulmonary arterial pressure. 5.2 Bradycardia Phenylephrine hydrochloride can cause severe bradycardia and decreased cardiac output. 5.3 Risk in Patients with Autonomic Dysfunction The pressor response to adrenergic drugs, including phenylephrine, can be increased in patients with autonomic dysfunction, as may occur with spinal cord injuries. 5.4 Skin and Subcutaneous Necrosis Extravasation of phenylephrine can cause necrosis or sloughing of tissue. 5.5 Pressor Effect with Concomitant Oxytocic Drugs Oxytocic drugs potentiate the pressor effect of sympathomimetic pressor amines including phenylephrine hydrochloride [see Drug Interactions (7.1)], with the potential for hemorrhagic stroke. 5.6 Allergic Reactions This product contains sodium metabisulfite, a sulfite that may cause allergic-type reactions, including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people. 5.7 Peripheral and Visceral Ischemia Phenylephrine hydrochloride can cause excessive peripheral and visceral vasoconstriction and ischemia to vital organs, particularly in patients with extensive peripheral vascular disease. 5.8 Renal Toxicity Phenylephrine hydrochloride can increase the need for renal replacement therapy in patients with septic shock. Monitor renal function.

DRUG INTERACTIONS 7.1 Agonists The pressor effect of phenylephrine hydrochloride is increased in patients receiving: Monoamine oxidase inhibitors (MAOI), such as selegiline. β-adrenergic blockers α-2 adrenergic agonists, such as clonidine Steroids Tricyclic antidepressants Norepinephrine transport inhibitors, such as atomoxetine Ergot alkaloids, such as methylergonovine maleate Centrally-acting sympatholytic agents, such as guanfacine or reserpine Atropine sulfate 7.2 Antagonists α-adrenergic blocking agents, including phenothiazines (e.g., chlorpromazine) and amiodarone block phenylephrine and are in turn blocked by phenylephrine.

ADVERSE REACTIONS The following adverse reactions associated with the use of phenylephrine hydrochloride were identified in the literature. 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: Bradycardia, AV block, ventricular extrasystoles, myocardial ischemia Gastrointestinal disorders: Nausea, vomiting General disorders and administrative site conditions: Chest pain, extravasation Immune system disorders: Sulfite sensitivity Nervous system disorders: Headache, nervousness, paresthesia, tremor Psychiatric disorders: Excitability Respiratory: Pulmonary edema, rales Skin and subcutaneous tissue disorders: Diaphoresis, pallor, piloerection, skin blanching, skin necrosis with extravasation Vascular disorders: Hypertensive crisis