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Composition:
Each tablet contains:
Allopurinol ............................... 100 mg or 300 mg.
Properties:
► Allopurinol
acts on purine catabolism, without
disrupting the biosynthesis of purines. It
reduces the production of uric acid by
inhibiting the biochemical reaction
immediately preceding its formation. Allopurinol is a structural analogue of the
natural
urine base, hypoxanthine. It is an
inhibitor of xanthene oxidase enzyme which
is responsible for the conversion of
hypoxanthine -----> Xanthene ------> uric acid, the end product of purine metabolism in
man.
► Allopurinol is
metabolized to the corresponding xanthene
analogue,oxipurinol ( alloxanthine ), which
is also an inhibitor of
xanthene oxidase.
Allopurinol is approximately 90% absorbed
from the gastro- intestinal tract. Peak
plasma levels generally
occurs at 1.5 hours
& 4.5 hours for Allopurinol & oxipurinol.
Approximately 20% of the ingested
Allopurinol is excreted in the
feces.
► Allopurinol
has a long plasma half-life, approximately
15.0 hours & therefore effective xanthene
oxidase inhibition is
maintained over a 24
hours period with a single daily dose of Allopurinol.
Indications:
To treat primary or
secondary hyperuricemia associated with
chronic gout, uric acid nephropathy, recurrent
uric acid stone formation, enzyme disorders,
blood disorders & cancer therapy.
Contraindications:
Patients who have developed a severe
reaction to Allopurinol should not be
restarted on the drug.
Precautions:
► Allopurinol should not be used for the treatment of an acute attack of gout.
► Allopurinol should be administered with care with renal or hepatic impairment.
Use during pregnancy & lactation:
Allopurinol should be used
during pregnancy only if clearly needed.
Caution should be exercised when Allopurinol
is administered to a nursing mother since it
is excreted in the breast milk.
Drug interaction:
► Allopurinol
prolongs the half-life of the anticoagulant,
dicoumarol. This should be noted when
Allopurinol is given to patients on
dicoumarol therapy.
► In patients
receiving mercaptopurine or azathioprine,
the concomitant administration of 300-600 mg
Allopurinol daily will require a reduction
in dose to approximately one-third to
one-fourth of the usual dose of
mercaptopurine or azathioprine.
► Concomitant
use of Allopurinol and thiazide diuretics
may contribute to enhancement of Allopurinol
toxicity in some patients.
► Renal function
should be monitored in patients on thiazide
diuretics and Allopurinol dosage levels
should be adjusted if diminished renal
function is detected.
► Concomitant
administration of uricosuric agents and
Allopurinol has been associated with a
decrease in oxypurine secretion and an
increase in urinary uric acid excretion
compared with that observed with Allopurinol
alone.
Dosage & route of
administration & duration:
► To reduce the possibility of precipitating acute gout:
Dose of 100 mg daily may be given initially
and increased by 100 mg daily at weekly
intervals until the concentration of uric
acid in plasma is about 60 mcg per ml.
The average daily dose is 200 to 300 mg for
those with mild gout & 400 to 600 mg for
those with moderately to severe gout.
Up to 300 mg may be taken as a single daily
dose, larger amount should be taken in
divided doses.
► Allopurinol is
best taken after meals. Doses should be
reduced in patients with impaired renal
function, 100 to 200 mg daily
should be used
if the creatinine clearance is between 10 &
20 ml per minute & not more than 100 mg
daily if the creatinine
clearance is less.
Adverse effects:
The most common side effect
of allopurinol is skin rash which may occur
more frequently in patients with renal
failure. Treatment with Allopurinol should
be discontinued immediately if a rash
develops.
Other side effects of less serious nature
include peripheral neuritis, nausea,
vomiting, abdominal pain diarrhea, headache
& drowsiness.
Storage:
Keep at temp. not exceeding 30°C.
Keep medicine out of reach of children.
Presentation:
Box of 30 or 1000 tablets (100 mg)
Box of 20 or 1000 tablets (300 mg)
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