Ephedrine

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Ephedrine.jpg

Ephedrine, and its diastereomer pseudoephedrine, are synthetic noncatecholamine sympathomimetic amines with both inotropic and chronotropic effects on α- and β-adrenergic receptors. It also increases endogenous norepinephrine release[1].

The cardiovascular effects of ephedrine resemble those of adrenaline, but its systemic blood pressure-increasing response is less intense and lasts approximately 10 times longer[2].

Ephedrine is commonly used as a stimulant, appetite suppressant, concentration aid, decongestant[3], to treat incontinence[4][5], and together with dopamine, can ameliorate hypotension associated with general anesthesia[6].

The hypertensive effects of ephedrine are shorter lasting (< 5 mins) compared with dopamine in dogs[7].

In use for canine incontinence, it appears less effective than phenylpropanolamine[8].

Adverse effects of ephedrine are dose-related and include tachycardia, hypertension, and metabolic acidosis[9], often associated with accidental overdosing, or consumption of herbal drinks containing large doses of ephedrine[10].

Recommended dose rate in dogs is 2.0 - 5.0 mg/kg given intravenously or orally.

References

  1. Hemmings HC & Hopkins PM (2006) Foundations of Anesthesia: Basic and Clinical Sciences. 2nd ed. London: Mosby. pp:413–414
  2. Egger C et al (2009) Efficacy of preanesthetic intramuscular administration of ephedrine for prevention of anesthesia-induced hypotension in cats and dogs. Can Vet J 50(2):179-184
  3. Rudolph K et al (2003) A model of allergic nasal congestion in dogs sensitized to ragweed. Am J Rhinol 17(4):227-232
  4. Noël S et al (2012) Urodynamic and haemodynamic effects of a single oral administration of ephedrine or phenylpropanolamine in continent female dogs. Vet J 192(1):89-95
  5. Arnold S (1997) Urinary incontinence in castrated bitches. 2. Diagnosis and treatment. Schweiz Arch Tierheilkd 139(7):319-324
  6. Sinclair MD & Dyson DH (2012) The impact of acepromazine on the efficacy of crystalloid, dextran or ephedrine treatment in hypotensive dogs under isoflurane anesthesia. Vet Anaesth Analg 39(6):563-573
  7. Chen HC et al (2007) Use of ephedrine and dopamine in dogs for the management of hypotension in routine clinical cases under isoflurane anesthesia. Vet Anaesth Analg 34(5):301-311
  8. Byron JK et al (2007) Effect of phenylpropanolamine and pseudoephedrine on the urethral pressure profile and continence scores of incontinent female dogs. J Vet Intern Med 21(1):47-53
  9. Webb AA & Shipton EA (1998) Re-evaluation of intramuscular ephedrine as prophylaxis against hypotension associated with spinal anaesthesia for Caesarean section. Can J Anaesth 45:367–369
  10. Ooms TG et al (2001) Suspected caffeine and ephedrine toxicosis resulting from ingestion of an herbal supplement containing guarana and ma huang in dogs: 47 cases (1997-1999). J Am Vet Med Assoc 218(2):225-229