1.1 Hypotension associated with Septic Shock

Epinephrine Injection USP, 1 mg/10 mL (0.1 mg/mL) is indicated to increase mean arterial blood pressure in adult patients with hypotension associated with septic shock.

2.1 General Considerations

Inspect visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Do not use if the solution is colored or cloudy, or if it contains particulate matter. Discard any unused portion.

2.2 Hypotension associated with Septic Shock

Dilute epinephrine in 5% Dextrose Injection, USP or 5% Dextrose and Sodium Chloride solution. These dextrose containing fluids provide protection against significant loss of potency by oxidation. Administration in saline solution alone is not recommended. If indicated, administer whole blood or plasma separately.
Add the entire contents of epinephrine prefilled syringe to 1000 mL of a 5% Dextrose containing solution. Each mL of this dilution contains 1 mcg of epinephrine.
Whenever possible, give infusions of epinephrine into a large vein. Avoid using a catheter tie-in technique, because the obstruction to blood flow around the tubing may cause stasis and increased local concentration of the drug. Avoid the veins of the leg in elderly patients or in those suffering from occlusive vascular diseases.
To provide hemodynamic support in septic shock associated hypotension in adult patients, the suggested dosing infusion rate of intravenously administered epinephrine is 0.05 mcg/kg/min to 2 mcg/kg/min, and is titrated to achieve a desired mean arterial pressure (MAP). The dosage may be adjusted periodically, such as every 10 to 15 minutes, in increments of 0.05 mcg/kg/min to 0.2 mcg/kg/min, to achieve the desired blood pressure goal.
After hemodynamic stabilization, wean incrementally over time, such as by decreasing doses of epinephrine every 30 minutes over a 12- to 24-hour period.

5.1 Hypertension

Because individual response to epinephrine may vary significantly, monitor blood pressure frequently and titrate to avoid excessive increases in blood pressure.
Patients receiving monoamine oxidase inhibitors (MAOI) or antidepressants of triptyline or imipramine types may experience severe, prolonged hypertension when given epinephrine.

5.2 Pulmonary Edema

Epinephrine increases cardiac output and causes peripheral vasoconstriction, which may result in pulmonary edema.

5.3 Cardiac Arrhythmias and Ischemia

Epinephrine may induce cardiac arrhythmias and myocardial ischemia in patients, especially patients suffering from coronary artery disease or cardiomyopathy [see Adverse Reactions (6) and Drug Interactions (7.3)].

5.4 Extravasation and Tissue Necrosis with Intravenous Infusion

Avoid extravasation of epinephrine into the tissues, to prevent local necrosis. When Epinephrine Injection is administered intravenously, check the infusion site frequently for free flow. Blanching along the course of the infused vein, sometimes without obvious extravasation, may be attributed to vasa vasorum constriction with increased permeability of the vein wall, permitting some leakage. This also may progress on rare occasions to superficial slough. Hence, if blanching occurs, consider changing the infusion site at intervals to allow the effects of local vasoconstriction to subside.
There is a potential for gangrene in a lower extremity when infusions of catecholamine are given in an ankle vein.
Antidote for Extravasation Ischemia: To prevent sloughing and necrosis in areas in which extravasation has taken place, infiltrate the area with 10 mL to 15 mL of saline solution containing from 5 mg to 10 mg of phentolamine, an adrenergic blocking agent. Use a syringe with a fine hypodermic needle, with the solution being infiltrated liberally throughout the area, which is easily identified by its cold, hard, and pallid appearance. Sympathetic blockade with phentolamine causes immediate and conspicuous local hyperemic changes if the area is infiltrated with 12 hours.

5.5 Renal Impairment

Epinephrine constricts renal blood vessels, which may result in oliguria or renal impairment.

5.6 Allergic Reactions Associated with Sulfite

Contains sodium bisulfite, which may cause mild to severe allergic reactions including anaphylaxis orasthmatic episodes, particularly in patients with a history of allergies. The presence of sodium bisulfite in this product should not preclude its use for the treatment of hypotension associated with septic shock, even if the patient is sulfite-sensitive, as the alternatives to using epinephrine in a life-threatening situation may not be satisfactory. In susceptible patients, consider using a formulation of epinephrine or another vasoconstrictor that does not contain sodium bisulfite.

7.1 Drugs Antagonizing Pressor Effects of Epinephrine

• α-blockers, such as phentolamine
• Vasodilators, such as nitrates
• Diuretics
• Antihypertensives
• Ergot alkaloids
• Phenothiazine antipsychotics

7.2 Drugs Potentiating Pressor Effects of Epinephrine

• Sympathomimetics
• β-blockers, such as propranolol
• Tricyclic anti-depressants
• Monoamine oxidase (MAO) inhibitors
• Catechol-O-methyl transferase (COMT) inhibitors, such as entacapon
• Clonidine
• Doxapram
• Oxytocin

7.3 Drugs Potentiating Arrhythmogenic Effects of Epinephrine

Patients who are concomitantly receiving any of the following drugs should be observed carefully for the development of cardiac arrhythmias [see Warnings and Precautions (5.6) and Adverse Reactions (6)].
• β-blockers, such as propranolol
• Cyclopropane or halogenated hydrocarbon anesthetics, such as halothane
• Antihistamines
• Thyroid hormones
• Diuretics
• Cardiac glycosides, such as digitalis glycosides
• Quinidine

7.4 Drugs Potentiating Hypokalemic Effects of Epinephrine

• Potassium depleting diuretics
• Corticosteroids
• Theophylline

8.1 Pregnancy

8.2 Lactation

8.4 Pediatric Use

Safety and effectiveness of epinephrine in pediatric patients with septic shock have not been established.

8.5 Geriatric Use

Clinical studies of epinephrine for the treatment of hypotension associated with septic shock did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

12.1 Mechanism of Action

Epinephrine acts on both alpha (α)- and beta (β)-adrenergic receptors. The mechanism of the rise in blood pressure is 3-fold: a direct myocardial stimulation that increases the strength of ventricular contraction (positive inotropic action), an increased heart rate (positive chronotropic action), and peripheral vasoconstriction.

12.2 Pharmacodynamics

Intravenous use for hypotension associated with septic shock
Following intravenous administration of epinephrine, increases in systolic blood pressure and heart rate are observed. Decreases in systemic vascular resistance and diastolic blood pressure are observed at low doses of epinephrine because of β2-mediated vasodilation, but are overtaken by α1-mediated peripheral vasoconstriction at higher doses leading to increase in diastolic blood pressure. The onset of blood pressure increase following an intravenous dose of epinephrine is < 5 minutes and the time to offset blood pressure response occurs within 20 min. Most vascular beds are constricted including renal, splanchnic, mucosal and skin.

12.3 Pharmacokinetics

Following intravenous injection, epinephrine is rapidly cleared from the plasma with an effective half-life of < 5 min. A pharmacokinetic steady state following continuous intravenous infusion is achieved within 10-15 min. In patients with septic shock, epinephrine displays dose-proportional pharmacokinetics in the infusion dose range of 0.03 to 1.7 mcg/kg/min.
Epinephrine is extensively metabolized with only a small amount excreted unchanged.
Epinephrine is rapidly degraded to vanillylmandelic acid, an inactive metabolite, by monoamine oxidase and catechol-O-methyltransferase that are abundantly expressed in the liver, kidneys and other extraneuronal tissues. The tissues with the highest contribution to removal of circulating exogenous epinephrine are the liver (32%), kidneys (25%), skeletal muscle (20%), and mesenteric organs (12%).

Specific Populations
Elderly
In a pharmacokinetic study of 45-minute epinephrine infusions given to healthy men aged 20 to 25 years and healthy men aged 60 to 65 years, the mean plasma metabolic clearance rate of epinephrine at steady state was greater among the older men (144.8 versus 78 mL/kg/min for a 14.3 ng/kg/min infusion).

Body Weight
Body weight has been found to influence epinephrine pharmacokinetics. Higher body weight was associated with a higher plasma epinephrine clearance and a lower concentration plateau.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term studies to evaluate the carcinogenic potential of epinephrine have not been conducted.
Epinephrine and other catecholamines have been shown to have mutagenic potential in vitro. Epinephrine was positive in the Salmonella bacterial reverse mutation assay, positive in the mouse lymphoma assay, and negative in the in vivo micronucleus assay. Epinephrine is an oxidative mutagen based on the E. coli WP2 Mutoxitest bacterial reverse mutation assay. This should not prevent the use of epinephrine under the conditions noted under the Indications and Usage.
The potential for epinephrine to impair reproductive performance has not been evaluated, but epinephrine has been shown to decrease implantation in female rabbits dosed subcutaneously with 1.2 mg/kg/day (15-fold the highest human intramuscular or subcutaneous daily dose) during gestation days 3 to 9.

13.2 Animal Toxicology and/or Pharmacology

Epinephrine was associated with metabolic effects, decreased mesentery, coronary and renal conductance in a sheep model of septic shock. Data from hemolysis study have shown that epinephrine at 1:1000 dilution is non-hemolytic. Epinephrine infusion significantly increased the MAP (69 vs. 86 mmHg) and cardiac output (6.4 vs. 7.1 L/min) and decreased renal blood flow (330 vs. 247 mL/min).

14.1 Hypotension associated with Septic Shock

Fourteen clinical studies from the literature documented that epinephrine increases the mean arterial pressure (MAP) in patients with hypotension associated with septic shock.