PHL-TRYPTOPHAN TABLET

Country: Canada

Language: English

Source: Health Canada

Active ingredient:

TRYPTOPHAN

Available from:

PHARMEL INC

ATC code:

N06AX02

INN (International Name):

TRYPTOPHAN

Dosage:

1G

Pharmaceutical form:

TABLET

Composition:

TRYPTOPHAN 1G

Administration route:

ORAL

Units in package:

250

Prescription type:

Prescription

Therapeutic area:

MISCELLANEOUS ANTIDEPRESSANTS

Product summary:

Active ingredient group (AIG) number: 0111038001; AHFS:

Authorization status:

CANCELLED POST MARKET

Authorization date:

2016-10-25

Summary of Product characteristics

PRODUCT MONOGRAPH
PHL-TRYPTOPHAN
(L-Tryptophan)
500 mg & 1 g Tablets
500mg Capsules
ADJUNCT IN THE MANAGEMENT OF AFFECTIVE DISORDERS
Pharmel Inc.
Date of Preparation:
8699, 8
th
Avenue
December 9, 2004
Montreal, Quebec, Canada
H1Z 2X4
CONTROL NUMBER:
095684, 095685
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phl-TRYPTOPHAN
(L-Tryptophan)
500 mg & 1g Tablets
500 mg Capsules
THERAPEUTIC CLASSIFICATION
Adjunct in the Management of Affective Disorders
ACTION AND CLINICAL PHARMACOLOGY
The rationale for the use of L-tryptophan in affective disorders is
based on clinical findings of
more than 20 years ago, that L-tryptophan increases 5-HT (serotonin)
synthesis in the central
nervous system of humans. It has been demonstrated in clinical trials
that oral ingestion of L-
tryptophan in humans caused a significant increase in the level of the
serotonin metabolite, 5-
hydroxyindoleacetic acid (5-HIAA), in the lumbar cerebrospinal fluid,
indicating an increased
turnover of serotonin in the CNS.
L-tryptophan is one of the eight essential amino acids. The minimum
daily requirements are
said to be 0.25 g for males and 0.15 g for females. It is present in
the hydrolysates of most
proteins, the average western diet containing between 1 and 3 grams
per day. There are two
major metabolic pathways for L-tryptophan, the first to serotonin, the
second to nicotinic acid.
Approximately 98% of dietary L-tryptophan is metabolized into
nicotinic acid and only a very
small amount is being metabolized to serotonin via the intermediary
stage of 5-hydroxy-
tryptophan (5-HTP). Tryptophan hydroxylase, the enzyme responsible for
this step, is the rate-
limiting enzyme for serotonin production and is normally only about
half-saturated. Central
nervous system serotonin is metabolized by monoamine oxidase to
5-HIAA.
A comparative bioavailability study was performed using phl-TRYPTOPHAN
1 g tablets
(Pharmel Inc.)
_versus_
TRYPTAN 1 g tablets (ICN Canada Ltd.) in 16 healthy male volunteers.
A single 1 g oral dose was administered. The results are summarized in
the following table:
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SUMMARY OF