Many shorter acting local anesthetics are readily absorbed into the blood from the injection site after administration. The duration of local action is therefore limited unless blood flow to the area is reduced. This can be accomplished by administration of a vasoconstrictor (usually an α-agonist sympathomimetic) with the local anesthetic agent. Cocaine is an important exception because it has intrinsic sympathomimetic action due to its inhibition of norepinephrine reuptake into nerve terminals.