Intravenous isoproterenol characteristically produces which pattern of haemodynamic change?

• A Increased systolic and increased diastolic pressure with reflex bradycardia
• B Raised diastolic pressure with unchanged systolic pressure
• C Decreased mean arterial pressure with decreased pulse pressure
• D Increased systolic pressure with little change in diastolic pressure and tachycardia ✓

Explanation

Isoproterenol is a non-selective beta agonist. Beta-1 stimulation increases heart rate and contractility, raising systolic pressure, while beta-2 mediated skeletal muscle vasodilation lowers diastolic pressure and total peripheral resistance. Because the baroreceptors see only modest mean pressure change, there is no reflex bradycardia and the tachycardia is direct. Option A describes norepinephrine-like effects, option C fits a pure vasodilator, and option B fits phenylephrine, which raises diastolic pressure selectively.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.