Why are vasoconstrictors used with local anesthetics in dentistry?

• A. To shorten anesthesia
• B. To prolong anesthesia, reduce peak blood levels, and minimize bleeding
• C. To increase bleeding
• D. No effect on bleeding

Answer: (B)

Vasoconstrictors are added to local anesthetics to keep the drug localized at the injection site. By narrowing the small blood vessels, they slow the anesthetic’s absorption into the bloodstream, so the nerve stays anesthetized longer (prolonged anesthesia) and there is less bleeding in the area (improved hemostasis). This slower absorption also means lower peak blood levels of the anesthetic, which reduces the risk of systemic toxicity and allows using a smaller total dose. Therefore, the combination both prolongs anesthesia and minimizes bleeding, rather than shortening duration or increasing bleeding.