Composition : Allopurinol Tablets IP
Allopurinol tablet is a prescription drug. It’s also available as a generic drug. Generic drugs usually cost less. Allopurinol also comes in an intravenous (IV) form, which is only given by a healthcare provider.Allopurinol may be used as part of a combination therapy. This means you may need to take it with other medications.Allopurinol is a xanthine oxidase enzyme inhibitor that is considered to be one of the most effective drugs used to decrease urate levels and is frequently used in the treatment of chronic gout.
Allopurinol is indicated for reducing urate/uric acid formation in conditions where urate/uric acid deposition has already occurred (e.g. gouty arthritis, skin tophi, nephrolithiasis) or is a predictable clinical risk (e.g. treatment of malignancy potentially leading to acute uric acid nephropathy). The main clinical conditions where urate/uric acid deposition may occur are: idiopathic gout; uric acid lithiasis; acute uric acid nephropathy; neoplastic disease and myeloproliferative disease with high cell turnover rates, in which high urate levels occur either spontaneously, or after cytotoxic therapy; certain enzyme disorders which lead to overproduction of urate, for example: hypoxanthine-guanine phosphoribosyl transferase, including Lesch-Nyhan syndrome; glucose-6-phosphatase including glycogen storage disease; phosphoribosyl pyrophosphate synthetase, phosphoribosyl pyrophosphateamido transferase; adenine phosphoribosyl transferase. Allopurinol is indicated for management of 2,8-dihydroxyadenine (2,8-DHA) renal stones related to deficient activity of adenine phosphoribosyl transferase.Allopurinol is indicated for the management of recurrent mixed calcium oxalate renal stones in the presence of hyperuricosuria, when fluid, dietary and similar measures have failed.
Allopurinol should not be administered to individuals known to be hypersensitive to allopurinol or to any of the following components of the formulation :Lactose, maize starch, povidone K-30 and Crospovidon.
Allopurinol decreases the production of uric acid by stopping the biochemical reactions that precede its formation. This process decreases urate and relieves the symptoms of gout, which may include painful tophi, joint pain, inflammation, redness, decreased range of motion, and swelling .
Mechanism of action :
Allopurinol is a structural analog of the natural purine base, hypoxanthine. After ingestion, allopurinol is metabolized to its active metabolite, oxypurinol (alloxanthine) in the liver, which acts as an inhibitor of xanthine oxidase enzyme.Allopurinol and its active metabolite inhibit xanthine oxidase, the enzyme that converts hypoxanthine to xanthine and xanthine to uric acid. Inhibition of this enzyme is responsible for the effects of allopurinol. This drug increases the reutilization of hypoxanthine and xanthine for nucleotide and nucleic acid synthesis by a process that involves the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRTase). This process results in an increased nucleotide concentration, which causes feedback inhibition of de novo purine synthesis. The end result is decreased urine and serum uric acid concentrations , which decreases the incidence of gout symptoms.Accompanying the reduction of serum uric acid by allopurinol is an increase in the serum and urine concentrations of hypoxanthine and xanthine (due to inhibition of xanthine oxidase). In the absence of allopurinol, regular urinary excretion of oxypurines almost entirely occurs in the form of uric acid. After the ingestion of allopurinol, the contents of excreted urine are hypoxanthine, xanthine, and uric acid. Because each substance has its own individual solubility, the concentration of uric acid in plasma is decreased without exposing the renal tissues to a high load of uric acid, thereby decreasing the risk of crystalluria. By lowering the uric acid concentration in the plasma below its limits of solubility, allopurinol encourages the dissolution of gout tophi. Although the levels of hypoxanthine and xanthine are found to be increased after allopurinol ingestion, the risk of deposition in renal tissues is less than that of uric acid, as they become more soluble and are rapidly excreted by the kidney.
Container pack: Do not store above 25°C. Store in the original container. Keep the container tightly closed.
Blister pack: Do not store above 25°C. Store in the original package.