L-tryptophan - Zohydro ER (Hydrocodone) Interaction
Herbal: L-tryptophan
Also Known As: L-Triptofano, L-Trypt, L-Tryptophane, Tryptophan
Drug: Hydrocodone
Brand names:
Hydrocodone, Zohydro ER

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 11, 2025
Interaction Details
Hydrocodone is classified as belonging to the following category: Cns Depressants
Theoretically, concomitant use of L-tryptophan with CNS depressants might cause additive sedative effects.
Clinical research shows that L-tryptophan can cause fatigue and drowsiness.
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
- Lieberman HR, Corkin S, Spring BJ. The effects of dietary neurotransmitter precursors on human behavior. Am J Clin Nutr 1985;42:366-70.
L-tryptophan Overview

Hydrocodone Overview
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Hydrocodone is used to relieve severe pain. Hydrocodone is only used to treat people who are expected to need medication to relieve severe pain around-the-clock for a long time and who cannot be treated with other medications or treatments. Hydrocodone extended-release (long-acting) capsules or extended-release tablets should not be used to treat pain that can be controlled by medication that is taken as needed. Hydrocodone is in a class of medications called opiate (narcotic) analgesics. It works by changing the way the brain and nervous system respond to pain.
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This monograph only includes information about the use of hydrocodone alone. If you are taking a hydrocodone combination product, be sure to read information about all the ingredients in the hydrocodone-combination monograph and ask your doctor or pharmacist for more information.
L-tryptophan - More Interactions
L-tryptophan interacts with 390 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.