MERCAPTOPURINE tablet

Country: United States

Language: English

Source: NLM (National Library of Medicine)

Active ingredient:

MERCAPTOPURINE (UNII: E7WED276I5) (MERCAPTOPURINE ANHYDROUS - UNII:PKK6MUZ20G)

Available from:

Avera McKennan Hospital

INN (International Name):

MERCAPTOPURINE

Composition:

MERCAPTOPURINE 50 mg

Prescription type:

PRESCRIPTION DRUG

Authorization status:

Abbreviated New Drug Application

Summary of Product characteristics

MERCAPTOPURINE- MERCAPTOPURINE TABLET
AVERA MCKENNAN HOSPITAL
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MERCAPTOPURINE TABLETS USP, 50 MG
RX ONLY
CAUTION
MERCAPTOPURINE IS A POTENT DRUG. IT SHOULD NOT BE USED UNLESS A
DIAGNOSIS OF ACUTE LYMPHATIC
LEUKEMIA HAS BEEN ADEQUATELY ESTABLISHED AND THE RESPONSIBLE PHYSICIAN
IS EXPERIENCED WITH THE
RISKS OF MERCAPTOPURINE AND KNOWLEDGEABLE IN ASSESSING RESPONSE TO
CHEMOTHERAPY.
DESCRIPTION
Mercaptopurine was synthesized and developed by Hitchings, Elion, and
associates at the Wellcome
Research Laboratories.
Mercaptopurine, known chemically as 6_H_-purine-6-thione,
1,7-dihydro-, monohydrate, is an analogue
of the purine bases adenine and hypoxanthine. Its structural formula
is:
Mercaptopurine is available in tablet form for oral administration.
Each scored tablet contains 50 mg
mercaptopurine and the inactive ingredients hypromellose, lactose
(anhydrous), lactose (monohydrate),
magnesium stearate, potato starch, sodium starch glycolate, starch and
stearic acid.
Each tablet meets the requirements of Test 2 for Dissolution in the
USP monograph for Mercaptopurine
Tablets, USP.
CLINICAL PHARMACOLOGY
MECHANISM OF ACTION
Mercaptopurine (6-MP) competes with hypoxanthine and guanine for the
enzyme hyphoxanthine-guanine
phosphoribosyltransferase (HGPRTase) and is itself converted to
thioinosinic acid (TIMP). This
intracellular nucleotide inhibits several reactions involving inosinic
acid (IMP), including the
conversion of IMP to xanthylic acid (XMP) and the conversion of IMP to
adenylic acid (AMP) via
adenylosuccinate (SAMP). In addition, 6-methylthioinosinate (MTIMP) is
formed by the methylation of
TIMP. Both TIMP and MTIMP have been reported to inhibit
glutamine-5-phosphoribosylpyrophosphate
amidotransferase, the first enzyme unique to the de novo pathway for
purine ribonucleotide synthesis.
Experiments indicate that radiolabeled mercaptopurine may be recovered
from the DNA in the form of
deoxythioguanosine. Some mercaptopurine is converted to nucleotide
derivatives of 6-thioguanine (6-
TG) by the sequential a