Depressive disorders: Note: Use as an adjunct to antidepressant therapy.
Oral: 8 to 12/g day in 3 to 4 divided doses.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in the manufacturer's labeling.
There are no dosage adjustments provided in the manufacturer's labeling.
Refer to adult dosing.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
Frequency not defined:
Gastrointestinal: Anorexia, nausea, xerostomia
Hypersensitivity: Hypersensitivity reaction (including edema, myalgia)
Nervous system: Disinhibition (sexual), dizziness, drowsiness, headache, serotonin syndrome
Hypersensitivity to tryptophan or any component of the formulation.
Concerns related to adverse effects:
• Cataracts: Patients may be more susceptible to cataract formation (especially if exposed to UV light) due to raised lenticular tryptophan and kynurenine concentrations.
• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery, driving).
• Hypersensitivity reactions: Hypersensitivity reactions (eg, edema, myalgia, pruritus, rash, urticaria, wheezing) have been reported.
• Serotonin syndrome: Potentially life-threatening serotonin syndrome has rarely occurred with concomitant use of tryptophan and serotonergic agents (eg, selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors). Monitor patients closely for signs of serotonin syndrome such as mental status changes (eg, agitation, hallucinations, delirium, coma), autonomic instability (eg, tachycardia, labile BP, diaphoresis), neuromuscular changes (eg, tremor, rigidity, myoclonus), GI symptoms (eg, nausea, vomiting, diarrhea), and/or seizures. Discontinue treatment (and any concomitant serotonergic agent) immediately if signs/symptoms arise.
Disease-related concerns:
• Achlorhydria: Patients with achlorhydria may be more susceptible to emphysema and pulmonary edema.
• Diabetes: Use with caution in patients with a history of diabetes.
• Protein deprived: Amino acid imbalance may occur in patients who are protein deprived and treated with tryptophan.
No
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral:
Tryptan: 500 mg
Generic: 500 mg
Tablet, Oral:
Tryptan: 500 mg, 1 g
Generic: 500 mg, 1 g
Oral: Administer with meals or snacks.
Note: Not approved in the United States.
Depressive disorders: Adjunct to antidepressant therapy in the management of patients with depressive disorders (eg, bipolar affective disorder).
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Almotriptan: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Alosetron: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Amphetamines: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability). Initiate amphetamines at lower doses, monitor frequently, and adjust doses as needed. Risk C: Monitor
Antiemetics (5HT3 Antagonists): May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Antipsychotic Agents: Serotonergic Agents (High Risk) may increase adverse/toxic effects of Antipsychotic Agents. Specifically, serotonergic agents may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotic Agents may increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Risk C: Monitor
BusPIRone: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Cyclobenzaprine: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Dapoxetine: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Do not use serotonergic agents (high risk) with dapoxetine or within 7 days of serotonergic agent discontinuation. Do not use dapoxetine within 14 days of monoamine oxidase inhibitor use. Dapoxetine labeling lists this combination as contraindicated. Risk X: Avoid
Dexmethylphenidate-Methylphenidate: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Dextromethorphan: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Diamorphine: May increase serotonergic effects of Tryptophan. This could result in serotonin syndrome. Risk X: Avoid
Eletriptan: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Ergot Derivatives: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Fenfluramine: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Risk C: Monitor
Gepirone: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Risk C: Monitor
Lasmiditan: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Levomethadone: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Linezolid: May increase serotonergic effects of Tryptophan. This could result in serotonin syndrome. Risk X: Avoid
Lithium: May increase serotonergic effects of Tryptophan. This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Metaxalone: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Methadone: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Methylene Blue: Tryptophan may increase serotonergic effects of Methylene Blue. This could result in serotonin syndrome. Risk X: Avoid
Metoclopramide: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Consider monitoring for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Monoamine Oxidase Inhibitors (Antidepressant): May increase serotonergic effects of Tryptophan. This could result in serotonin syndrome. Risk X: Avoid
Monoamine Oxidase Inhibitors (Type B): May increase serotonergic effects of Serotonergic Agents (High Risk, Miscellaneous). This could result in serotonin syndrome. Risk X: Avoid
Nefazodone: May increase serotonergic effects of Serotonergic Agents (High Risk, Miscellaneous). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Ondansetron: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Opioid Agonists (metabolized by CYP3A4 and CYP2D6): May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Opioid Agonists (metabolized by CYP3A4): May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Opioid Agonists: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Opipramol: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Oxitriptan: Serotonergic Agents (High Risk) may increase serotonergic effects of Oxitriptan. This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
OxyCODONE: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Ramosetron: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Selective Serotonin Reuptake Inhibitor: Serotonergic Agents (High Risk, Miscellaneous) may increase serotonergic effects of Selective Serotonin Reuptake Inhibitor. This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Serotonergic Non-Opioid CNS Depressants: Serotonergic Agents (High Risk, Miscellaneous) may increase serotonergic effects of Serotonergic Non-Opioid CNS Depressants. This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Serotonergic Opioids (High Risk): May increase serotonergic effects of Serotonergic Agents (High Risk, Miscellaneous). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) if these agents are combined. Risk C: Monitor
Serotonin 5-HT1D Receptor Agonists (Triptans): May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Serotonin/Norepinephrine Reuptake Inhibitor: May increase serotonergic effects of Serotonergic Agents (High Risk, Miscellaneous). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
St John's Wort: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. St John's Wort may decrease serum concentration of Serotonergic Agents (High Risk). Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Syrian Rue: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Tilidine: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Tricyclic Antidepressants: May increase serotonergic effects of Serotonergic Agents (High Risk, Miscellaneous). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Ziprasidone: May increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Risk C: Monitor
Endogenous tryptophan crosses the placenta (Kamimura 1991).
Tryptophan is an essential amino acid. Enzymes in the placenta regulate endogenous tryptophan metabolism and fetal exposure via the serotonin and kynurenine pathways. Endogenous tryptophan and its metabolites are needed for placentation, fetal development, and immune regulation during pregnancy. The kynurenine pathway plays an essential role in preventing the maternal immune system from rejecting the developing fetus. Neonatal concentrations decrease 24 hours after birth (Kamimura 1991; Karahoda 2020).
Maternal concentrations of endogenous tryptophan and metabolites vary as pregnancy progresses (Duan 2018; Teshigawara 2019). Fluctuations in endogenous maternal tryptophan concentrations may impact metabolism and influence the development of postpartum depression (Duan 2018; Trujillo 2018). Information related to tryptophan supplementation to prevent postpartum depression in limited (Dowlati 2017; Dowlati 2021).
Tryptophan is present in breast milk (Dowlati 2015; Kamimura 1991).
Concentrations of endogenous tryptophan (total and unbound/free) are highest in the colostrum. Concentrations in breast milk decrease from 5 to 7 days postpartum and decline over 30 days after delivery (Kamimura 1991; Zanardo 1989).
Tryptophan breast milk concentrations may increase following supplementation. Breastfeeding patients 2 to 24 months postpartum were administered a single oral dose of tryptophan 2 g (n=6) or 4 g (n=6). Breast milk was sampled prior to and for 6 hours after the dose. Breast milk concentrations of total tryptophan were not significantly increased above baseline. Concentrations of unbound/free tryptophan showed a dose-dependent increase, peaking 2 hours after the dose, then decreasing over 6 hours. Free tryptophan concentrations in 12 infant formulas were also measured. Two formulas had free tryptophan concentrations below the limit of detection. Free concentrations of tryptophan in the remaining infant formulas were similar to or greater than the concentrations of unbound/free tryptophan measured in breast milk following the single oral dose (Dowlati 2015).
An essential amino acid which is a precursor to serotonin
Metabolism: ~98% is metabolized into nicotinic acid and only a small amount into serotonin via the intermediary stage of 5-hydroxy-tryptophan. CNS serotonin is metabolized by monoamine oxidase to 5-HIAA.