Which of the following local anaesthetic is a strong vasoconstrictor?
High-Yield Explanation
Cocaine inhibits the neuronal membrane transpoers for catecholamines, thereby potentiating the effect of NE at adrenergic receptors in the vasculature, resulting in vasoconstriction and reduced cocaine absorption in vascular beds where adrenergic effects predominate. Ropivacaine and bupivacaine also cause vasoconstriction. Cocaine is used only in the nose, nasopharynx, mouth, throat, and ear, where it uniquely produces vasoconstriction as well as anesthesia. The shrinking of mucous membranes decreases operative bleeding while improving surgical visualization. Comparable vasoconstriction can be achieved with other local anesthetics by the addition of a low concentration of a vasoconstrictor such as phenylephrine (0.005%). Ref: Catterall W.A., Mackie K. (2011). Chapter 20. Local Anesthetics. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e.