Pharmacology A drug ‘X’ is an a adrenergic blocker but paradoxically produces vasoconstriction. ‘X’ is: A Phenoxybenzamine B Ergotamine C Prazosin receptors D Tolazoline 💡 Explanation A drug 'X' is an a adrenergic blocker but paradoxically produces vasoconstriction. 'X' is: ✓ Correct Answer: B. Ergotamine