epinephrine; adrenaline (Sus-Phrine, Vapronefrin, Epifrin, Glaucon, Auvi-Q, Allerject)

Indications

• acute bronchospasm, status asthmaticus
• dyspnea & wheezing due to severe asthma
• bronchiolitis
• severe allergic reaction, anaphylaxis, anaphylactive reactions
• cardiac arrest, cardiopulmonary resuscitation
• hypotension, shock syndromes
• cardiac arrhythmias
• local anesthesia
  • in combination with local anesthetics to reduce vascular absorption of the anesthetic
• management of open-angle glaucoma
• mydriasis

Benefit/risk

• bronchiolitis
  • number needed to treat to prevent 1 hospital admission = 17

Dosage

Pressor activity:

• Infusion 1 mg in 250 mL D5W (4 ug/mL) at 1-4 ug/min (15-60 mL/hr).

Injection:

• solution:
  • SC: 1 mg/mL (1:1000) (1 mL & 30 mL)
  • IV: 0.1 mg/mL (1:10,000) (10 mL)
  • IM: (anaphylaxis)
• suspension: 1.5 mg/0.3 mL (1:200) (5 mL)
• auto-injector: 0.15 mg/dose, 0.3 mg/dose
  • auto-injector Auvi-Q comes with audio & visual cues on how to administer the medication properly

Asthma: 0.01 mL/kg up to 0.3-0.5 mL (0.3-0.5 mg) of 1:1000 solution SC.

• Injectable allergy kit: Tradenames: Ana-kit, Epipen.
• Sustained epinephrine: Tradename: Sus-Phrine.
  • 0.05 mL/kg up to 0.15 mL of 1:200 solution
  • SC every 6 hours.

Racemic epinephrine. Tradename: Vapronefrin.

• Croup: 8-15 drops nebulized. ,

Intranasal: neffy, an intranasal epinephrine delivery device

• comparable or more effective than approved injection products

Ophthalmic: Epifrin eyedrops: 0.5%, 1% & 2% (10 mL).

• Adjunctive treatment of open-angle glaucoma.
  • 1-2 drops OU QD/BID.

Cautions:

• gonioscopy required before initiation of treatment
• do not use in closed-angle glaucoma

Pharmacokinetics

• onset of action is < 5 minutes
• metabolism
  • liver, kidneys, adrenergic nerve terminals & plasma
  • monoamine oxidase (MAO)
  • catechol O-methyltransferase (COMT)
  • metabolites: homovanillic acid (HVA) & norepinephrine
• eliminated in the urine
• 1/2life 2-10 minutes
• ophthalmic agent (Epifrin)
  • initial reduction in intraocular pressure within 1 hour
  • maximal effect in 4-8 hours
  • duration of action 12-24 hours

elimination via plasma

Adverse effects

• common (> 10%)
  • tachycardia, nervousness, restlessness, palpitations
• less common (1-10%)
  • dizziness, lightheadedness, flushing, headache, increased sweating, hypertension, nausea/vomiting, trembling, insomnia, paleness, weakness
• uncommon (< 1%)
  • chest pain, arrhythmias, wheezing, dry mouth or throat, sudden death, anxiety, urinary retention
• other
  • increased myocardial oxygen consumption
  • decreased renal & splanchnic blood flow
  • ventricular ectopy
  • increased systolic blood pressure
  • disorientation
  • shortness of breath
  • facilitates AV conduction - may cause rapid ventricular response in patients with atrial fibrillation
  • contains sulfite (asthmatics may be sensitive)
  • gangrene of extremities & ears j ophthalmic agent: (Epifrin)
    • exacerbation of narrow-angle glaucoma
    • macular edema (30%)

• drug adverse effects of adrenergic receptor agonists
• drug adverse effects of beta-adrenergic receptor agonists
• drug adverse effects of sympathomimetic(s)

Drug interactions

• alpha & beta blockers antagonize effects of epinephrine
• tricyclic antidepressants (TCA) increase cardiac irritability by inhibiting re-uptake
• general anesthetics increase cardiac irritability

Mechanism of action

• full sympathetic agonist, alpha 1 & 2, beta 1 & 2
• affinity for adrenergic receptors
  • beta-1 adrenergic receptor > beta-2 adrenergic receptor
  • alpha-1 adrenergic receptor = beta-1 adrenergic receptor
• respiratory effects
  • beta-2 agonist activity relaxes bronchial smooth muscle
  • constricts bronchial arterioles
  • relieves bronchospasm
  • reduces congestion & edema
  • increases tidal volume
  • no respiratory effects are durable
  • antagonizes histamine release & binding
• cardiovascular effects
  • beta-1 agonism produces positive inotropic & chronotropic effects
  • increased systemic vascular resistance
• ophthalmic agent (Epifrin)
  • reduction of aqueous humor production
  • increased aqueous outflow

More general terms

• catecholamine
• beta-adrenergic receptor agonist
• vasoconstrictor agent or vasopressor

More specific terms

• adrenochrome
• epinephrine inhaler (Asthmanefrin, Primatene Mist)

Additional terms

• adrenergic receptor
• epinephrine in plasma
• epinephrine metabolism

Component of

• epinephrine/zinc phenolsufonate
• epinephrine/zinc chloride
• epinephrine/prilocaine
• epinephrine/etidocaine
• bupivacaine/epinephrine/fentanyl
• bupivacaine/epinephrine
• epinephrine autoinjector (Epipen, Symjepi)
• epinephrine/lidocaine; lidocaine (Xylocaine) with epinephrine
• epinephrine/pilocarpine (E-Pilo-x PxEx)
• insect sting or anaphylaxis kit (Ana-Kit)
• articaine/epinephrine (Septocaine)
• lidocaine/epinephrine topical (LidoSite)
• epinephrine inhaler (Asthmanefrin, Primatene Mist)

Database

• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=838
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5816
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=247704
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5924
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=441411
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=9489
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=89249
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=181464