Drug reference

Tryptophan

Essential amino acid (sleep aid / depression adjunct) · Antidepressant

Also known as L-Tryptophan

START

1–2 g PO at bedtime (insomnia adjunct)

TYPICAL MAX

6 g/day

STOP IF

Eosinophilia/myalgia symptoms or serotonin syndrome

WATCH

Pharmaceutical-grade source; serotonergic co-medication

CDSCO approvedATC N06AX02

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 45min · absorption
PEAK: 2h · Tmax
t½: 1.8h · t½
DURATION: 7h · per dose

EXCRETION

Renal — kynurenine/5-HTP metabolites

route + CYP

INTERACTIONS

12 major

incl. contraindicated

PREGNANCY

Avoid pharmacologic doses; nutritional intake fine.

FDA category + note

Top interactionssee all 12 →

Mao InhibitorsContraindicatedDatabaseKimi deep-research + Cla
MoclobemideSevereTextbookG&G 14e
AmitriptylineSevereDatabaseDDInter
AmoxapineSevereDatabaseDDInter

Mechanism

Essential amino acid that is precursor to serotonin and melatonin; supplementation modestly raises CNS serotonin synthesis with mild sedative/antidepressant effect; also a niacin (NAD) precursor.

Indications

Adjunct in depression (with antidepressants)Mild sleep disturbance / insomniaAffective disorders (specialist)

Dosing

Adult: 1–3 g PO at bedtime for sleep; 3–6 g/day in 3 divided doses for depression adjunct (specialist).
Pediatric: Generally not recommended.
Renal adjustment: Caution in severe renal impairment.
Hepatic adjustment: Avoid in significant hepatic disease.
Geriatric: Lower doses; monitor sedation.
Max dose: 6 g/day

Pharmacokinetics

Onset

Sleep effect 30–60 min; mood over weeks

Peak effect

~2 h (Tmax)

Duration

~6–8 h

Half-life

~1.5–2 h

Bioavailability

Well absorbed orally

Protein binding

~85% (albumin)

Metabolism

Hepatic kynurenine pathway and 5-HTP pathway

Excretion

Renal (metabolites)

Contraindications

History of eosinophilia-myalgia syndrome (EMS — historical contaminated batches)
Severe hepatic / renal impairment
Concomitant MAO inhibitors
Hypersensitivity

Side effects

Common

NauseaDrowsinessHeadacheLight-headedness

Serious

Eosinophilia-myalgia syndrome (1989 epidemic — contaminated source)
Serotonin syndrome (with serotonergic drugs)
Severe hypersensitivity

Pregnancy & lactation

Pregnancy

Avoid pharmacologic doses; nutritional intake fine.

Lactation

Avoid pharmacologic doses; nutritional intake compatible.

Drug interactions

Mao Inhibitors

Contraindicated

Database

Markedly increased serotonin synthesis + reduced metabolism

Contraindicated

Source: Kimi deep-research + Cla

Moclobemide

Severe

Textbook

Serotonin syndrome, characterized by hyperthermia, muscle rigidity, myoclonus, tremors, autonomic instability, confusion, irritability, and agitation, which can progress to coma and death.

Avoid coadministration.

Source: G&G 14e

Amitriptyline

Severe

Database

Drug interaction classified as: synergy

Source: DDInter

Amoxapine

Severe

Database

Drug interaction classified as: synergy

Source: DDInter