Local anesthesia injections may contain epinephrine to achieve which effect?

• A. Vasoconstriction and reduced bleeding
• B. Prolongation of anesthesia
• C. Increased bleeding tendency
• D. Dilated bronchioles

Answer: (A)

Epinephrine in local anesthesia is added to constrict small blood vessels at the injection site. This vasoconstriction slows the escape of the anesthetic into the bloodstream, which reduces bleeding during the procedure and helps keep the anesthetic working in the area longer. While the decreased blood flow also contributes to a longer duration of numbness, the primary effect being demonstrated here is vasoconstriction with reduced bleeding. Dilated bronchioles are a systemic beta-adrenergic effect of epinephrine, not the intended local action, and increased bleeding would be the opposite of what epinephrine does in this context.