Complementary/Alternative Medicine: This monograph describes a natural or herbal product that is not subject to FDA guidelines for medicines. Patients and clinicians are advised to read package labels carefully to ensure safe and efficacious use.
L-tryptophan is an essential amino acid that is converted by the body to 5–hydroxytryptophan (5–HTP) and then to serotonin. Both L-tryptophan and 5–HTP cross the blood-brain barrier and have sedative effects. Depletion of endogenous tryptophan can cause a relapse in depression symptoms.
* CAPITALS indicate life-threatening. Underline indicate most frequent.
Natural Drug Interaction
Increased risk of serotonergic effects and serotonin syndrome with SSRIs, dextromethorphan, meperidine, tricyclic antidepressants, monoamine oxidase inhibitors, and tramadol.
Increased sedation with CNS depressants.
Additive sedation with herbs or supplements that have sedative properties such as kava St. John's wort valerian 5–HTP and others.
Increased risk of serotonin syndrome with St. John's wort. .
PO (Adults): Insomnia– 1 gram 20 minutes before bedtime; Depression– 300 mg/day; Prementrual syndrome– 6 grams/day; Smoking cessation– 50 mg/kg/day.
Capsules: Tablets: 500 mg
Assess sleep patterns prior to and periodically during therapy.
Monitor for signs and symptoms of esosinophilia-myalgia sydrome (severe myalgia, arthralgia, intense eosinophilia) Less common symptoms include respiratory prodrome (cough, dyspnea, pulmonary infiltrates), limb edema, scleroderma, mononeuritis, evanescent skin rash, mild LFT elevations, and leukocytosis. If these symptoms occur, discontinue l-tryptophan.
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