All of the following are true regarding vasoconstrictors added to anesthetics except:

All of the following are true regarding vasoconstrictors added to anesthetics except:

• A. LA blood levels are increased
• B. Increase duration
• C. Promote hemostasis
• D. Reduce toxicity risk

Answer: (A)

The main idea is that adding a vasoconstrictor to a local anesthetic mainly reduces blood flow at the injection site, which slows how fast the drug enters the bloodstream and keeps it active longer where it’s needed. Because of this local vasoconstriction, systemic absorption is limited, so blood levels of the anesthetic do not rise; in fact they are reduced. This is why vasoconstrictors prolong the duration of anesthesia, help control bleeding (hemostasis), and lower the risk of systemic toxicity by keeping the drug localized longer and at lower peak concentrations. The statement that blood levels are increased is not true; increased blood levels would imply more systemic exposure, which vasoconstrictors are designed to avoid.

The main idea is that adding a vasoconstrictor to a local anesthetic mainly reduces blood flow at the injection site, which slows how fast the drug enters the bloodstream and keeps it active longer where it’s needed. Because of this local vasoconstriction, systemic absorption is limited, so blood levels of the anesthetic do not rise; in fact they are reduced. This is why vasoconstrictors prolong the duration of anesthesia, help control bleeding (hemostasis), and lower the risk of systemic toxicity by keeping the drug localized longer and at lower peak concentrations. The statement that blood levels are increased is not true; increased blood levels would imply more systemic exposure, which vasoconstrictors are designed to avoid.