Vasoconstrictors, such as levonordefrin, are added to local anesthetics primarily to?

Vasoconstrictors like levonordefrin are added to local anesthetics primarily to prolong the duration of the local anesthetic. By constricting blood vessels in the area of injection, vasoconstrictors reduce blood flow, which slows the absorption of the anesthetic into the bloodstream. This allows the anesthetic to remain in the target area longer, enhancing its effect and providing a prolonged period of numbness.

This is particularly important in dental procedures where extended anesthesia is often required to ensure patient comfort. In addition to prolonging the effect, the reduced blood flow helps to minimize systemic absorption of the anesthetic, which can decrease the risk of potential side effects associated with higher plasma levels of the drug.