Complications Adverse reaction to the anesthetic or delivery vehicle (eg, allergic reaction to the anesthetic [rare] or to methylparaben [a preservative]) Toxicity due to anesthetic overdose (eg, seizure, cardiac arrhythmias) or sympathomimetic effects due to epinephrine (if using an anesthetic - epinephrine mixture) Intravascular injection of anesthetic or epinephrine Hematoma (eg, due to puncture of the infraorbital venous plexus) Neuritis Spread of infection, by passing the needle through an infected area Most complications result from inaccurate needle placement.