Drugs affecting the autonomic nervous system

Severe blood pressure elevation following ephedrine administration during carotid endarterectomy under general anesthesia: A CARE-compliant case report

“…Among the vasopressors commonly used during surgery, phenylephrine and vasopressin are selective α-adrenergic receptor agonists that increase total peripheral vascular resistance and have no direct effect on cardiac contractility. [6] In the present case, blood pressure decreased immediately after it had markedly increased earlier. Therefore, phenylephrine was continuously administered, and no particular adverse reactions were observed; this finding is similar to other cases in which sympathetic denervation supersensitivity was reported.…”

“…Ephedrine is a sympathomimetic drug that stimulates both α- and β-adrenergic receptors by the endogenous release of norepinephrine, thereby increasing blood pressure, cardiac output, and stroke volume. [5,6] This indirect action can lead to the development of tachyphylaxis following the depletion of noradrenaline from nerve terminals. [6] Thus, it should be noted that in the present case, the systolic blood pressure increased by approximately 20 mm Hg after the intravenous administration of 4 mg ephedrine at the early stage of surgery, but 90 minutes later, it rapidly increased by 125 mm Hg (from 90 to 215 mm Hg) after the same small dose of ephedrine was administered.…”

“…[5,6] This indirect action can lead to the development of tachyphylaxis following the depletion of noradrenaline from nerve terminals. [6] Thus, it should be noted that in the present case, the systolic blood pressure increased by approximately 20 mm Hg after the intravenous administration of 4 mg ephedrine at the early stage of surgery, but 90 minutes later, it rapidly increased by 125 mm Hg (from 90 to 215 mm Hg) after the same small dose of ephedrine was administered. It is also noteworthy that ephedrine, which is often used as a vasopressor in CEA surgery, can cause this reaction.…”