epinephrine

[ep″ĭ-nef´rin]

a hormone produced by the adrenal medulla; called also adrenaline (British). Its function is to aid in the regulation of the sympathetic branch of the autonomic nervous system. At times when a person is highly stimulated, as by fear, anger, or some challenging situation, extra amounts of epinephrine are released into the bloodstream, preparing the body for energetic action. Epinephrine is a powerful vasopressor that increases blood pressure and increases the heart rate and cardiac output. It also increases glycogenolysis and the release of glucose from the liver, so that a person has a suddenly increased feeling of muscular strength and aggressiveness.ƒ

Some disorders of the adrenal glands, such as addison's disease, reduce the output of epinephrine below normal. By contrast, excessive activity of those glands, as sometimes seen in highly emotional persons, tends to produce tenseness, palpitation, high blood pressure, perhaps diarrhea, and overaggressiveness. Certain adrenal tumors also result in the production of too much epinephrine. Removal of the tumor relieves symptoms.

Epinephrine is also produced synthetically and can be administered parenterally, topically, or by inhalation. It acts as a vasoconstrictor, antispasmodic, and sympathomimetic, and it is used as an emergency heart stimulant as well as to relieve symptoms in allergic conditions such as urticaria (hives), asthma, and other conditions requiring bronchodilation and as a adjunct to local and regional anesthesia. It is the most effective drug for counteracting the lethal effects of anaphylactic shock. It is also used topically in the eye in the treatment of glaucoma.

epinephrine

Twinject

epinephrine hydrochloride

Adrenalin Chloride (CA), Anapen (UK), Epi-E-Z Pen (CA), EpiPen, EpiPen Jr.

Pharmacologic class: Sympathomimetic (direct acting)

Therapeutic class: Bronchodilator, mydriatic

Pregnancy risk category C

Action

Stimulates alpha- and beta-adrenergic receptors, causing relaxation of cardiac and bronchial smooth muscle and dilation of skeletal muscles. Also decreases aqueous humor production, increases aqueous outflow, and dilates pupils by contracting dilator muscle.

Availability

Auto-injector for I.M. injection: 1:2,000 (0.5 mg/ml)

Injection: 0.1 mg/ml, 0.5 mg/ml, 1 mg/ml

Ophthalmic drops: 0.5%, 1%, 2% Solution for inhalation (as racepinephrine): 2.5% (equivalent to 1% epinephrine)

Indications and dosages

➣ Bronchodilation; anaphylaxis; hypersensitivity reaction

Adults: 0.1 to 0.5 ml of 1:1,000 solution subcutaneously or I.M., repeated q 10 to 15 minutes p.r.n. Or 0.1 to 0.25 ml of 1:10,000 solution I.V. slowly over 5 to 10 minutes; may repeat q 5 to 15 minutes p.r.n. or follow with a continuous infusion of 1 mcg/minute, increased to 4 mcg/minute p.r.n. For emergency treatment, EpiPen delivers 0.3 mg I.M. of 1:1,000 epinephrine.

Children: For emergency treatment, EpiPen Jr. delivers 0.15 mg I.M. of 1:2,000 epinephrine.

➣ Acute asthma attack

Adults and children ages 4 and older: One to three deep inhalations of inhalation solution with hand-held nebulizer, repeated q 3 hours p.r.n.

➣ To restore cardiac rhythm in cardiac arrest

Adults: 0.5 to 1 mg I.V., repeated q 3 to 5 minutes, if needed. If no response, may give 3 to 5 mg I.V. q 3 to 5 minutes.

➣ Chronic simple glaucoma

Adults: One drop in affected eye once or twice daily. Adjust dosage to meet patient's needs.

➣ To prolong local anesthetic effects

Adults and children: 1:200,000 concentration with local anesthetic

Contraindications

• Hypersensitivity to drug, its components, or sulfites

• Angle-closure glaucoma

• Cardiac dilatation, cardiac insufficiency

• Cerebral arteriosclerosis, organic brain syndrome

• Shock with use of general anesthetics and halogenated hydrocarbons or cyclosporine

• MAO inhibitor use within past 14 days

• Labor

• Breastfeeding

Precautions

Use cautiously in:

• hypertension, hyperthyroidism, diabetes, prostatic hypertrophy

• elderly patients

• pregnant patients

• children.

Administration

• In anaphylaxis, use I.M. route, not subcutaneous route, if possible.

☞ Inject EpiPen and EpiPen Jr. only into anterolateral aspect of thigh. Don't inject into buttocks or give I.V.

☞ Be aware that not all epinephrine solutions can be given I.V. Check manufacturer's label.

• For I.V. injection, give each 1-mg dose over at least 1 minute. For continuous infusion, use rate of 1 to 10 mcg/minute, adjusting to desired response.

• Use Epi-Pen Jr. for patients weighing less than 30 kg (66 lb).

☞ Don't give within 14 days of MAO inhibitors.

Adverse reactions

CNS: nervousness, anxiety, tremor, vertigo, headache, disorientation, agitation, drowsiness, fear, dizziness, asthenia,cerebral hemorrhage, cerebrovascular accident (CVA)

CV: palpitations, widened pulse pressure, hypertension, tachycardia, angina, ECG changes,ventricular fibrillation, shock

GI: nausea, vomiting

GU: decreased urinary output, urinary retention, dysuria

Respiratory: dyspnea, pulmonary edema

Skin: urticaria, pallor, diaphoresis, necrosis

Other: hemorrhage at injection site

Interactions

Drug-drug. Alpha-adrenergic blockers: hypotension from unopposed beta-adrenergic effects

Antihistamines, thyroid hormone, tricyclic antidepressants: severe sympathomimetic effects

Beta-adrenergic blockers (such as propranolol): vasodilation and reflex tachycardia

Cardiac glycosides, general anesthetics: increased risk of ventricular arrhythmias

Diuretics: decreased vascular response Doxapram, mazindol, methylphenidate: enhanced CNS stimulation or pressor effects

Ergot alkaloids: decreased vasoconstriction

Guanadrel, guanethidine: enhanced pressor effects of epinephrine

Levodopa: increased risk of arrhythmias

Levothyroxine: potentiation of epinephrine effects

MAO inhibitors: increased risk of hypertensive crisis

Drug-diagnostic tests. Glucose: transient elevation

Lactic acid: elevated level (with prolonged use)

Patient monitoring

☞ Monitor vital signs, ECG, and cardiovascular and respiratory status. Watch for ventricular fibrillation, tachycardia, arrhythmias, and signs and symptoms of shock. Ask patient about anginal pain.

• Assess drug's effect on underlying problem (such as anaphylaxis or asthma attack), and repeat dose as needed.

☞ Monitor neurologic status, particularly for decreased level of consciousness and other signs and symptoms of cerebral hemorrhage or CVA.

• Monitor fluid intake and output, watching for urinary retention or decreased urinary output.

• Inspect injection site for hemorrhage or skin necrosis.

Patient teaching

• Teach patient who uses auto-injector how to use syringe correctly, when to inject drug, and when to repeat doses.

• Teach patient who uses hand-held nebulizer correct use of equipment and drug. Explain indications for both initial dose and repeat doses.

☞ Inform patient that drug may cause serious adverse effects. Tell him which symptoms to report.

• If patient will self-administer drug outside of health care setting, explain need for prompt evaluation by a health care provider to ensure that underlying disorder has been corrected.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

ep·i·neph·rine

(ep'i-nef'rin),

A catecholamine that is the chief neurohormone of the adrenal medulla of most species; also secreted by certain neurons. The l-isomer is the most potent stimulant (sympathomimetic) of adrenergic α- and β-receptors, resulting in increased heart rate and force of contraction, vasoconstriction or vasodilation, relaxation of bronchiolar and intestinal smooth muscle, glycogenolysis, lipolysis, and other metabolic effects; used in the treatment of bronchial asthma, acute allergic disorders, open-angle glaucoma, cardiac arrest, and heart block, and as a topical and local vasoconstrictor. Generally used salts are epinephrine hydrochloride and epinephrine bitartrate, the latter most frequently used in topical preparations.
See also: emergency theory, fight or flight response.

Synonym(s): adrenaline

[epi- + G. nephros, kidney, + -ine]

epinephrine

also

epinephrin

(ĕp′ə-nĕf′rĭn)

1. A hormone secreted by the adrenal medulla that is released into the bloodstream in response to physical or mental stress, as from fear or injury. It initiates many bodily responses, including the stimulation of heart action and an increase in blood pressure, metabolic rate, and blood glucose concentration. Also called adrenaline.

2. A white to brownish crystalline compound, C₉H₁₃NO₃, isolated from the adrenal glands of certain mammals or synthesized and used in medicine as a heart stimulant, vasoconstrictor, and bronchial relaxant.

adrenaline

A sympathomimetic catecholamine hormone synthesised in the adrenal medulla and released into the circulation in response to hypoglycemia and sympathetic nervous system—i.e., splanchnic nerve stimulation due to exercise and stress; it acts on α- and β-receptors, resulting in vasoconstriction or vasodilation, decreased peripheral blood flow, increased heart rate, increased force of contractility, increased glycogenolysis and increased lipolysis. Pharmacologic doses of epinephrine are used as bronchodilator for acute asthma, to increase blood pressure and in acute myocardial infarctions, to improve myocardial and cerebral blood flow. Adrenaline is the official British pharmacopoeia name for epinephrine.

epinephrine

Physiology A sympathomimetic catecholamine hormone synthesized in the adrenal medulla and released into the circulation in response to hypoglycemia and sympathetic nervous system–splanchnic nerve stimulation due to exercise and stress; it acts on α– and β-receptors, resulting in vasoconstriction or vasodilation, ↓ peripheral blood flow, ↑ heart rate, ↑ force of contractility, ↑ glycogenolysis, ↑ lipolysis; pharmacologic epinephrine is used as bronchodilator for acute asthma to ↑ BP and in acute MIs to improve myocardial and cerebral blood flow. See Fight-or-flight response, High-dose epinephrine.

ep·i·neph·rine

(ep'i-nef'rin)

A catecholamine that is the chief neurohormone of the medulla of the suprarenal gland. The l-isomer is the most potent stimulant (sympathomimetic) of adrenergic α- and β-receptors, resulting in increased heart rate and force of contraction, vasoconstriction or vasodilation, relaxation of bronchiolar and intestinal smooth muscle, glycogenolysis, lipolysis, and other metabolic effects; used in the treatment of bronchial asthma, acute allergic disorders, open-angle glaucoma, and heart block, and as a topical and local vasoconstrictor.
Synonym(s): adrenaline.

[epi- + G. nephros, kidney, + -ine]

epinephrine

ADRENALINE. Epinephrine is the favoured medical usage in the USA, but the term ‘adrenaline’ is in popular use. The drug is on the WHO official list. The terms ad and renal are Latin for ‘on’ and ‘kidney’. The corresponding terms in Greek are epi and nephron .

epinephrine

see ADRENALINE.

Epinephrine

Also called adrenalin, a secretion of the adrenal glands (along with norepinephrine) that helps the liver release glucose and limits the release of insulin. Norepinephrine is both a hormone and a neurotransmitter, a substance that transmits nerve signals.

Mentioned in: Adrenal Gland Cancer, Catecholamines Tests, Hypoglycemia, Liposuction, Smoking

adrenaline (epinephrine)

A hormone of the adrenal medulla which, instilled in the eye, causes a constriction of the conjunctival vessels, dilates the pupil and diminishes the intraocular pressure. See adrenergic receptors; ocular decongestant; naphazoline; neurotransmitter; noradrenaline (norepinephrine).

ep·i·neph·rine

(ep'i-nef'rin)

A catecholamine that is the chief neurohormone of the adrenal medulla of most species; also secreted by some neurons; used to treat bronchial asthma, acute allergic disorders, open-angle glaucoma, cardiac arrest, and heart block, and as a topical and local vasoconstrictor.
Synonym(s): adrenaline.

[epi- + G. nephros, kidney, + -ine]