Epinephrine; Adrenaline

Epinephrine (adrenaline)

Brand Name: epinephrine bitartrate

Pregnancy Category C

Drug classes: Sympathomimetic drug, Alpha-adrenergic agonist, Beta₁ and beta₂-adrenergic agonist, Cardiac stimulant, Vasopressor, Bronchodilator, Antiasthmatic drug, Nasal decongestant, Mydriatic, Antiglaucoma drug

 

Therapeutic actions

Naturally occurring neurotransmitter, the effects of which are mediated by alpha or beta receptors in target organs. Effects on alpha receptors include vasoconstriction, contraction of dilator muscles of iris. Effects on beta receptors include positive chronotropic and inotropic effects on the heart (beta₁ receptors); bronchodilation, vasodilation, and uterine relaxation (beta₂ receptors); decreased production of aqueous humor.

 

Indications

· Intravenous: In ventricular standstill after other measures have failed to restore circulation, given by trained personnel by intracardiac puncture and intramyocardial injection; treatment and prophylaxis of cardiac arrest and attacks of transitory AV heart block with syncopal seizures (Stokes-Adams syndrome); syncope due to carotid sinus syndrome; acute hypersensitivity (anaphylactoid) reactions, serum sickness, urticaria, angioneurotic edema; in acute asthmatic attacks to relieve bronchospasm not controlled by inhalation or SC injection; relaxation of uterine musculature; additive to local anesthetic solutions for injection to prolong their duration of action and limit systemic absorption

· Injection: Relief from respiratory distress of bronchial asthma, chronic bronchitis, emphysema, other COPDs

· Aerosols and solutions for nebulization: Temporary relief from acute attacks of bronchial asthma, COPD

· Topical nasal solution: Temporary relief from nasal and nasopharyngeal mucosal congestion due to a cold, sinusitis, hay fever, or other upper respiratory allergies; adjunctive therapy in middle ear infections by decreasing congestion around eustachian ostia

· 0.25%–2% ophthalmic solutions: Management of open-angle (chronic simple) glaucoma, often in combination with miotics or other drugs

· 0.1% ophthalmic solution: Conjunctivitis, during eye surgery to control bleeding, to produce mydriasis

 

Contraindications

· Contraindicated with allergy or hypersensitivity to epinephrine or components of preparation (many of the inhalant and ophthalmic products contain sulfites: sodium bisulfite, sodium or potassium metabisulfite; check label before using any of these products in a sulfite-sensitive patient); narrow-angle glaucoma; shock other than anaphylactic shock; hypovolemia; general anesthesia with halogenated hydrocarbons or cyclopropane; organic brain damage, cerebral arteriosclerosis; cardiac dilation and coronary insufficiency; tachyarrhythmias; ischemic heart disease; hypertension; renal dysfunction (drug may initially decrease renal blood flow); COPD patients who have developed degenerative heart disease; diabetes mellitus; hyperthyroidism; lactation.

Adverse effects

Fear, anxiety, tenseness, restlessness, headache, light-headedness, dizziness, drowsiness, tremor, insomnia, hallucinations, psychological disturbances, convulsions, CNS depression, weakness, blurred vision, ocular irritation, tearing, photophobia, symptoms of paranoid schizophrenia

Arrhythmias, hypertension resulting in intracranial hemorrhage, cardiovascular collapse with hypotension, palpitations, tachycardia, precordial pain in patients with ischemic heart disease

Nausea, vomiting, anorexia

Constriction of renal blood vessels and decreased urine formation (initial parenteral administration), dysuria, vesical sphincter spasm resulting in difficult and painful urination, urinary retention in males with prostatism

Pallor, respiratory difficulty, orofacial dystonia, sweating

Headache, browache, blurred vision, photophobia, difficulty with night vision, pigmentary (adrenochrome) deposits in the cornea, conjunctiva, or lids with prolonged use

Transitory stinging on initial instillation, eye pain or ache, conjunctival hyperemia

 

Drug Interactions:

· Increased sympathomimetic effects with other TCAs (eg, imipramine)

· Excessive hypertension with propranolol, beta-blockers, furazolidone

· Decreased cardiostimulating and bronchodilating effects with beta-adrenergic blockers (eg, propranolol)

· Decreased vasopressor effects with chlorpromazine, phenothiazines

· Decreased antihypertensive effect of guanethidine, methyldopa

 

Nursing considerations

· Use extreme caution when calculating and preparing doses; epinephrine is a very potent drug; small errors in dosage can cause serious adverse effects. Double-check pediatric dosage.

· Use minimal doses for minimal periods of time; "epinephrine-fastness" (a form of drug tolerance) can occur with prolonged use.

· Protect drug solutions from light, extreme heat, and freezing; do not use pink or brown solutions. Drug solutions should be clear and colorless (does not apply to suspension for injection).

· Shake the suspension for injection well before withdrawing the dose.

· Rotate SC injection sites to prevent necrosis; monitor injection sites frequently.

· Maintain a rapidly acting alpha-adrenergic blocker (phentolamine) or a vasodilator (a nitrate) on standby in case of excessive hypertensive reaction.

· Maintain an alpha-adrenergic blocker or facilities for intermittent positive pressure breathing on standby in case pulmonary edema occurs.

· Maintain a beta-adrenergic blocker (propranolol; a cardioselective beta-blocker, such as atenolol, should be used in patients with respiratory distress) on standby in case cardiac arrhythmias occur.

· Do not exceed recommended dosage of inhalation products; administer pressurized inhalation drug forms during second half of inspiration, because the airways are open wider and the aerosol distribution is more extensive. If a second inhalation is needed, administer at peak effect of previous dose, 3–5 min.

· Use topical nasal solutions only for acute states; do not use for longer than 3–5 days, and do not exceed recommended dosage. Rebound nasal congestion can occur after vasoconstriction subsides.