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(trip-tuh-fan) ,


(trade name)


Therapeutic: mood stabilizers
Premenstrual dysphoric disorder (PMDD)Depression.Smoking cessation.Insomnia.


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.

Therapeutic effects

Improved symptoms of depression.
Improved sleep.


Absorption: Unknown
Distribution: Unknown
Metabolism and Excretion: Unknown
Half-life: Unknown

Time/action profile



Contraindicated in: Hypersensitivity.Pregnancy and lactation.
Use Cautiously in: Eosinophilia.Kidney disease.Liver disease.

Adverse Reactions/Side Effects

Central nervous system

  • ataxia
  • headache
  • drowsiness
  • lightheadedness

Ear, Eye, Nose, Throat

  • visual blurring


  • heartburn
  • abdominal pain
  • dry mouth
  • nausea


  • eosinophilia-myalgia syndrome


Increased risk of serotonergic effects and serotonin syndrome with SSRIs,dextromethorphan,meperidine,tricyclic antidepressantsmonoamine oxidase inhibitorspentazocine andtramadol. Increased sedation with CNS depressants. Additive sedation with herbs or supplements that have sedative properties such as kavaSt. John's wortvalerian5–HTPand others.Increased risk of serotonin syndrome with St. John's wort.
Oral (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

Nursing implications

Nursing assessment

  • 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.

Potential Nursing Diagnoses

Deficient knowledge, related to medication regimen (Patient/Family Teaching)


  • Oral: Administer without regard to food.

Patient/Family Teaching

  • Instruct patient to take as directed; do not take more than directed.
  • Advise patient to notify health care professional of symptoms of esosinophilia-myalgia sydrome occur.
  • Advise female patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes

  • Improvement in insomnia and premenstrual disorder.
Drug Guide, © 2015 Farlex and Partners


The biologically active form of the amino acid tryptophan. It is sold as a dietary supplement for use as a sleep aid and mood enhancer.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
References in periodicals archive ?
L-tryptophan (TRP) is aromatic amino acid, and research and clinical trials have been widely conducted due to critical role in metabolic functions (Richard et al., 2009).
In the aforementioned synthesis of the PbS films doped systematically with the biomolecule L-tryptophan solution labelled ([V.sub.[L-tryptophan]]), we proceed to prepare the glass substrates, which were previously immersed in a [K.sub.2][Cr.sub.2][O.sub.7]:HCl:[H.sub.2]O solution for ~24.0 h, after which they were rinsed in deionised water (~18.2 M[ohms]) and dried in a clean and hot air flow.
Improving crop yields by the application of an auxin precursor L-tryptophan. Pakistan J.
In the control group, L-tryptophan (L-Trp) (100 [micro]g/ml) was added at the time of infection.
The stimulatory effects of L-tryptophan and plant growth promoting rhizobacteria (PGPR) on soil health and physiology of wheat.
The patient used Life Extension[R] supplements to boost L-tryptophan (mood) and iodine (thyroid function), along with acupuncture and exercise to elevate mood and manage other symptoms.
The filtrate from each suspension was distributed into 27 aliquots with 100 mL in each flask, and divided into 9 groups based on the amounts of L-tryptophan, fructan, or casein added to each flask (Table 1).
Cashews are a good source of L-tryptophan, the amino acid that is necessary for healthy serotonin production, making them a perfect go-to snack to help you feel calm and in control.
I just started reading my June WDJ, and when glancing at "What's Ahead" I was terribly excited to see that you are going to do something on L-Tryptophan.
Key Words: Nephrostomy tube, purple urine, PUBS, long-term indwelling catheter, alkaline urine, indoxyl sulfate, L-Tryptophan.