Lidocaine and epinephrine and Promethazine interaction
Lidocaine and epinephrine and Promethazine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Promethazine (PROMETHAZINE HYDROCHLORIDE) label · effective 2026-04-16
Epinephrine Because of the potential for Promethazine to reverse epinephrine's vasopressor effect, epinephrine should NOT be used to treat hypotension associated with Promethazine Syrup overdose.
It should be used with caution in persons with seizure disorders or in persons who are using concomitant medications, such as narcotics or local anesthetics, which may also affect seizure threshold.
From the Lidocaine and epinephrine (Flavalta) label · effective 2026-03-31
Possible early warning signs of central nervous system (CNS) toxicity are restlessness, anxiety, incoherent speech, lightheadedness, metallic taste, tinnitus, dizziness, blurred vision, tremors, twitching, CNS depression, or drowsiness.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.