a. Indications. Vasoconstrictors (like epinephrine) are sometimes used in conjunction with local anesthetics. Vasoconstrictors are used to prolong the duration of action of local anesthetics. Vasoconstrictors also help to control bleeding. Furthermore, the vasoconstrictor delays the absorption of the local anesthetic by reducing the blood flow to the affected area. This results in a reduction of the toxic effects of the local anesthetic, since the rate of absorption keeps pace with the rate the
local anesthetic is metabolized by the body. Vasoconstrictors are of no value in delaying the absorption of the local anesthetic from mucous membranes (that is, topical blocks).
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