Lithium - Phenergan (Promethazine) Interaction
Herbal: Lithium
Also Known As: Carbonate de Lithium, Citrate de Lithium, Lithium Aspartate, Lithium Carbonate, Lithium Citrate, Lithium Gluconate, Lithium Orotate, Lithium Sulfate, Litio, Numéro Atomique 3, Orotate de Lithium
Drug: Promethazine
Brand names:
Phenergan

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 18, 2025
Interaction Details
Promethazine is classified as belonging to the following category: Phenothiazines
Theoretically, taking lithium supplements with phenothiazines might decrease the levels and clinical effects of phenothiazines.
Concomitant use of lithium with phenothiazines might reduce lithium concentrations. Lithium might also reduce phenothiazine concentrations, making the pharmacokinetic effect unpredictable. It is unclear if these interactions would occur with the smaller doses found in lithium supplements.
Interaction Rating
Likelihood of Occurrence
ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
References
- Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
- McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
Lithium Overview

Promethazine Overview
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Promethazine is used to relieve the symptoms of allergic reactions such as allergic rhinitis (runny nose and watery eyes caused by allergy to pollen, mold or dust), allergic conjunctivitis (red, watery eyes caused by allergies), allergic skin reactions, and allergic reactions to blood or plasma products. Promethazine is used with other medications to treat anaphylaxis (sudden, severe allergic reactions) and the symptoms of the common cold such as sneezing, cough, and runny nose. Promethazine is also used to relax and sedate patients before and after surgery, during labor, and at other times. Promethazine is also used to prevent and control nausea and vomiting that may occur after surgery, and with other medications to help relieve pain after surgery. Promethazine is also used to prevent and treat motion sickness. Promethazine helps control symptoms, but will not treat the cause of the symptoms or speed recovery. Promethazine is in a class of medications called phenothiazines. It works by blocking the action of a certain natural substance in the body.
Lithium - More Interactions
Lithium interacts with 511 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
Unknown | No interactions have been reported or no interaction data is currently available. |
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DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
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Drug descriptions are provided by MedlinePlus.