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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.
Pharmacologic class: Sympathomimetic (direct acting)
Therapeutic class: Bronchodilator, mydriatic
Pregnancy risk category C
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.
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
• 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
Use cautiously in:
• hypertension, hyperthyroidism, diabetes, prostatic hypertrophy
• elderly patients
• pregnant patients
• 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.
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
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)
☞ 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.
• 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.
See also: emergency theory, fight or flight response.
epinephrine/epi·neph·rine/ (-nef´rin) a catecholamine hormone secreted by the adrenal medulla and a central nervous system neurotransmitter released by some neurons. It is stored in chromaffin granules and is released in response to hypoglycemia, stress, and other factors. It is a potent stimulator of the sympathetic nervous system (adrenergic receptors), and a powerful vasopressor, increasing blood pressure, stimulating the heart muscle, accelerating the heart rate, and increasing cardiac output. It is used as a topical vasoconstrictor, cardiac stimulant, systemic antiallergic, bronchodilator, and topical antiglaucoma agent; for the last two uses it is also administered as the bitartrate salt. Called also adrenaline (Great Britain).
adrenalineA 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.
epinephrinePhysiology 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.
epinephrineADRENALINE. 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 .
epinephrineadrenaline; catecholamine neurohormone, released from adrenal medulla as part of the ‘fight or flight’ mechanism, i.e. the unconscious and automatic response to real or perceived danger (Table 1); most potent stimulant (sympathomimetic) of adrenergic alpha and beta receptors (see Table 2); added to local anaesthetic (LA) solutions (e.g. lidocaine or bupivacaine, at 1:200 000, equivalent to 5 µg/mL of LA) as a vasoconstrictor, so that anaesthetic is absorbed more slowly into systemic circulation, anaesthetic effect is prolonged and a smaller dose of the drug can be administered (note: LA solutions containing epinephrine must never be injected into a digit; they should be avoided in pregnant women as epinephrine can cross the placenta to affect the fetus); drug of choice in immediate treatment of anaphylaxis, delivered by intramuscular injection at rate of 500 µg (0.5 mL of a 1:1000 solution) every 5 minutes to a maximum of three doses for a 70-kg adult
|Site of action||Effects|
|Cardiac effects||Rapid increase in heart rate|
Increase in the force of contraction of the heart muscle
|Blood vessels||Vasoconstriction of blood vessels in skin|
Vasodilatation or vasoconstriction of local blood vessels, depending on whether they carry alpha or beta receptors
|Smooth muscle||Relaxation of smooth muscle|
Relaxation of gut muscle
|Hepatic effects||Glycogenolysis (causing an increase in circulating glucose)|
It is recommended that the use of adrenaline should be avoided in pregnant women as it can cross the placenta to cause systemic effects in the fetus.
|Alpha-1 (a1); postsynaptic||Vasoconstriction; positive inotropism; antidiuresis||Adrenaline +|
|Alpha-2 (a2); presynaptic||Vasodilatation; inhibition of noradrenaline release||Adrenaline +|
|Alpha-2 (a2); postsynaptic||Constriction of coronary arteries; promotion of salt and water excretion||Adrenaline +|
|Beta-1 (ß1); postsynaptic||Positive inotropism; chronotropism; renin release||Adrenaline ++|
|Beta-2 (ß2); presynaptic||Noradrenaline release accelerated; positive inotropism; chronotropism||Adrenaline +|
|Beta-2 (ß2); postsynaptic||Vasodilatation; relaxation of bronchial smooth muscle||Adrenaline +|
|Dopamine1; postsynaptic||Vasodilatation; diuresis||Dopamine ++|
|Dopamine1; presynaptic||Inhibits noradrenaline release||Dopamine +|
Plus signs indicate degree of effect.
drug class: adrenergic agonist, catecholamine;
action: β1- and β2-agonist, causing increased levels of cAMP, producing bronchodilation and cardiac stimulation;
uses: acute asthmatic attacks, hemostasis, bronchospasm, anaphylaxis, allergic reactions, cardiac arrest, vasopressor. Recommended for the dental office or clinic emergency kit. See EpiPen.