Tradename
Harpagin
Generic Name
Benzbromarone, Allopurinol
Category
Hepatobiliary System
Form
Tablets
Composition
Benzbromarone...............20 mg
Allopurinol.....................100 mg
Description
Properties/Actions
Pharmacology
Allopurinol acts on purine metabolism without disrupting the biosynthesis of purines. It reduces the production of uric acid by inhibiting the biochemical reactions immediately preceding its formation. The degree of this decrease is dose-dependent. Allopurinol is a structure analgoue of the natural purine base, hypoxanthine. It is an inhibitor of xanthine oxidase, the enzyme responsible for the conversion of hypoxanthine to xanthine and xanthine to uric acid, the end product of purine metabolism in man. Allopurinol is metabolized to the corresponding xanthine analogue, oxypurinol (alloxanthine) which also is an inhibitor of xanthine oxidase. Allopurinol reduces both the serum and urinary uric acid levels by inhibiting the formation of uriac aicd.
Benzbromarone, a uricosuric agent, lowers the serum uric acid level by increasing urinary excretion of uric acid. This is done by inhibiting the proximal tubular reabsorption of uric acid in nephrons.

Pharmacokinetics
Allopurinol is rapidly absorbed after its ingestion and reaches peak plasma concentration within 30 to 60 minutes. On average, 20% is excreted through the feces in a lapse of 48 to 72 hours. Non-absorbed allopurinol is rapidly eliminated from the plasma with a mean life of 2 to 3 hours, as it its converted to alloxanthine. Less than 10% of a single dose or an average of 30% of the medicine taken for longer periods is excreted through the urine. Allopurinol and its metabolite alloxanthine are distributed along the total tissular water, except on the cerebrum, where its concentration is 33% of the concentration observed in the rest of the tissues. Neither compound is linked to plasmatic proteins; their concentrations in plasma have no direct relation to their therapeutic or toxic effects.
Benzbromarone is only partially absorbed from the gastrointestinal tract, reaching peak plasma concentration about 2 to 4 hours after an oral dose. Benzbromarone is extensively bound to plasma proteins. It is metabolized by the liver, and is excreted mainly in the feces, with a small amount appearing in the urine.
Indications
Harpagin is indicated for all forms of uric acid accumulation in blood (primary and secondary hyperuricemia). It is not, however, suitable for use in acute attacks of gout.
Contraindications
Harpagin is contraindicated in:
  • Severe disturbances of renal function (creatinine clearance below 5 ml/min gouty nephropathy)
  • Pregnancy and lactation
  • Hypersensitivity to Harpagin
  • Haemochromatosis
  • Children under 14 years
Drug Interactions
The following interactions were reported:
  • The metabolism of 6-mercaptopurine is inhibited by Harpagin, thus the dose of Azathioprine or 6-mercapopurine should be reduced to the quarter when the drugs are given concomitantly.
  • Harpagin may interefere with the hepatic inactivation of oral anticoagulants.
  • Harpagin may delay the elimination of probenecid and increase its concentration in plasma.
Side Effects/Adverse Effects
Transient gastrointestinal disturbances, and allergic skin reactions may specifically appear.
Exfoliative dermatitis, cholestasis, cephalgia, tiredness, and dizziness seldom appear. Such complaints disappear when therapy is over. It is also possible for therapy to go ahead by declining dose. Leucopenia and thrombocytopenia seldom appear.
Pregnancy & Lactation
Harpagin should not be used during pregnancy or breastfeeding.Harpa
Dosage & Administration
Unless otherwise prescribed by the physician, the recommended dose is 1 film-coated tablet to be swallowed whole once or twice daily after meals with plenty of fluid.
Overdosage
Warnings
Harpagin (allopurinol) should be discotninued at the first appearance of skin rash or other signs which may indicate an allergic reaaction. In some instances, a skin rash may be followed by more severe hypersensitivity reactions such as exfoliative, urticarial and purpuric lesion as well as Steven's Johnson syndrome (erythema multiform exsudativum), and/or general vasculitis, and irreversible hepatotoxicity.
Notes
Storage
Store below 30°C, protected from light.
Packaging
Box containing 3 strips of 10 film-coated tablets each.
Manufacturer
Marcryl Pharma
Date Added/Updated
18th April 2012 2:22 am
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