Acetyl-l-carnitine - Dextromethorphan HBr, Phenylephrine HCl Interaction
Herbal: Acetyl-l-carnitine
Also Known As: Acetil-L-Carnitina, Acetyl Carnitine, Acétyl Carnitine, Acetyl L-Carnitine, Acétyl-L-Carnitine, Acetyl-L-Carnitine Arginate Dihydrochloride, Acetyl-L-Carnitine Arginate HCl, Acétyl-L-Carnitine Arginate HCl, Acetyl-L-Carnitine HCl
Drug: Dextromethorphan HBr, Phenylephrine HCl
Brand names:
Vicks Formula 44D Cough & Head Congestion Relief

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Dextromethorphan HBr, Phenylephrine HCl is classified as belonging to the following category: Serotonergic Drugs
Theoretically, acetyl-L-carnitine might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders, when taken with serotonergic drugs.
Animal research shows that acetyl-L-carnitine can increase levels of serotonin in the brain.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Veronese N, Stubbs B, Solmi M, Ajnakina O, Carvalho AF, Maggi S. Acetyl-L-Carnitine Supplementation and the Treatment of Depressive Symptoms: A Systematic Review and Meta-Analysis. Psychosom Med. 2018;80(2):154-9.
Acetyl-l-carnitine Overview

Acetyl-l-carnitine - More Interactions
Acetyl-l-carnitine interacts with 200 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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Parts of this content are provided by the Therapeutic Research Center, LLC.
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.