Reflex tachycardia is most likely to occur after the systemic administration of: (A) albuterol, (B) methoxamine, (C) phenylephrine, (D) propranolol
Answer is A. Although used primarily via inhalation for asthma, systemic effects of albuterol include vasodilation due to its b2 receptor activation. This can result in a decrease in PVR and mean BP, which elicits a reflex tachycardia. Methoxamine and phenylephrine are a- receptor activators causing vasoconstriction, which would result in reflex bradycardia. Ganglion blockers (trimethaphan) prevent autonomic reflexes, and a reflex increase in heart rate could not occur in the presence of a beta blocker (propranolol).