L-tryptophan - Actiq (Fentanyl Citrate, Oral Transmucosal Fentanyl Citrate) Interaction
Herbal: L-tryptophan
Also Known As: L-Triptofano, L-Trypt, L-Tryptophane, Tryptophan
Drug: Fentanyl Citrate, Oral Transmucosal Fentanyl Citrate
Brand names:
Actiq
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 11, 2025
Interaction Details
Fentanyl Citrate, Oral Transmucosal Fentanyl Citrate 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.
Interaction Details
Fentanyl Citrate, Oral Transmucosal Fentanyl Citrate is classified as belonging to the following category: Serotonergic Drugs
Theoretically, combining L-tryptophan with serotonergic drugs might cause additive serotonergic effects.
L-tryptophan is a precursor to serotonin. Theoretically, combining serotonergic drugs with L-tryptophan might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders.
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
- Messiha FS. Fluoxetine: adverse effects and drug-drug interactions. J Toxicol Clin Toxicol 1993;31:603-30.
- Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3.
L-tryptophan Overview
L-tryptophan is an essential amino acid found in proteins. "Essential" amino acids are not produced in our bodies and must obtained from the diet. L-tryptophan is commonly used as a dietary supplement to help with sleep and mood disorders, and is a precursor to the neurotransmitter serotonin. Serotonin is involved in the regulation of sleep, mood, and other functions.
Fentanyl Citrate, Oral Transmucosal Fentanyl Citrate Overview
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Fentanyl is used to treat breakthrough pain (sudden episodes of pain that occur despite round the clock treatment with pain medication) in cancer patients at least 18 years of age (or at least 16 years of age if using Actiq brand lozenges) who are taking regularly scheduled doses of another narcotic (opiate) pain medication, and who are tolerant (used to the effects of the medication) to narcotic pain medications. Fentanyl is in a class of medications called narcotic (opiate) analgesics. It works by changing the way the brain and nervous system respond to pain.
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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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.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.
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In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
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