Harpagin
Harpagin Uses, Dosage, Side Effects, Food Interaction and all others data.
Allopurinol is a xanthine oxidase inhibitor which is administered orally. It acts on purine catabolism without disrupting the biosynthesis of purine. It reduces the production of uric acid by inhibiting the biochemical reactions immediately preceding its formation. Allopurinol is a structural analogue 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
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 .
Benzbromarone has been used in trials studying the basic science and treatment of Heart Failure, Hyperuricemia, Chronic Kidney Disease, Abnormal Renal Function, and Gout and Asymptomatic Hyperuricemia.
Trade Name | Harpagin |
Generic | Allopurinol + Benzbromarone |
Type | |
Therapeutic Class | |
Manufacturer | |
Available Country | Egypt |
Last Updated: | September 19, 2023 at 7:00 am |
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Uses
Allopurinol is used for prevention and treatment of high blood uric acid level and gout, prevents deposition of urate crystal in kidney, serous membranes of liver, heart, air sac and joints of poultry.
Benzbromarone is a uricosuric agent which is taken daily for the prevention of gout flares.
Harpagin is also used to associated treatment for these conditions: Hyperuricemia, Primary Gout, Recurrent calcium oxalate calculi, Secondary gout, Calcium oxalate calculi Renal CalculiGouty Arthritis
How Harpagin works
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 .
Dosage
Harpagin dosage
Poultry- 25 mg/kg body or 2.5 gm/liter water for 3-5 days, or as directed by registered veterinarian.
Side Effects
The most frequent adverse reaction to Allopurinol is skin rash such as, pruritic maculopapular skin eruptions, sometimes scaly or exfoliative.
Toxicity
Oral TDLO (rat): 10 mg/kg; Oral LD50 (mouse): 78 mg/kg; Oral TDLO (mouse): 100 mg/kg
Use in pregnancy
Reproductive studies have been completed using rats and rabbit models at doses up to twenty times the normal human dose ( about 5 mg/kg per day), and it was concluded that fertility was not impaired and there was no fetal harm. There is a published report of a study in pregnant mice administered 50 or 100 mg/kg allopurinol intraperitoneally on gestation days 10 or 13. There were increased numbers of dead fetuses in dams administered 100 mg/kg allopurinol, however, death did not occur in those given 50 mg/kg. There were higher numbers of external malformations in fetuses at both doses of allopurinol on gestation day 10 and higher numbers of skeletal malformations in fetuses at both doses on gestation day 13. Despite the above findings, there are no adequate or well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if it is absolutely required .
Use in nursing
Both allopurinol and the metabolite oxipurinol have been found in the milk of a mother who was receiving allopurinol. Since the effect of allopurinol on the nursing infant is unknown, it is advisable to exercise caution when allopurinol is taken by a nursing woman .
Mutagenicity and carcinogenicity
Cytogenic studies demonstrate that allopurinol does not induce chromosomal abnormalities in human blood cells in vitro at concentrations up to 100 g/mL and in vivo at doses up to 60 mg/day for an average duration of 40 months. Allopurinol does not form nitroso compounds (which may be carcinogenic) or affect lymphocyte transformation in vitro. Evidence suggests that allopurinol does not have deleterious effects on DNA at any stage of the cell cycle and was not found to be mutagenic. No evidence of carcinogenicity has been observed in mice treated with allopurinol for up to a 2 year period .
Precaution
Before you use discuss with your doctor if you are allergic to it or its ingredients.
Interaction
Anticoagulant: Allopurinol prolongs the half life of the anticoagulant, dicumarol.
Diuretic: Concomitant use of Allopurinol and thiazide diuretics may contribute to the enhancement of Allopurinol toxicity.
Cytotoxic agent: Enhanced bone marrow suppression by cyclophosphamide and other cytotoxic agent has been reported among patients with neoplastic disease.
Volume of Distribution
Allopurinol and oxypurinol are both substrates for the enzyme xanthine oxidase, which is present in the cytoplasm of endothelial cells of capillaries, including sinusoids, with the highest activity demonstrated in the liver and intestinal lining. Tissue concentrations of allopurinol have not yet been reported in humans, however, it is probable that allopurinol and the metabolite oxypurinol would be measured in the highest concentrations in the abovementioned tissues. In animals, allopurinol concentrations are found to reach the highest levels in the blood, liver, intestine and heart, and lowest in the brain and lung tissues .
Elimination Route
This drug is about 90% absorbed from the gastrointestinal tract. Peak plasma levels normally occur at 1.5 hours and 4.5 hours post-dose for allopurinol and oxipurinol respectively. Following one oral dose of 300 mg of allopurinol, maximum plasma levels of about 3 mcg/mL of allopurinol and 6.5 mcg/mL of oxipurinol were measured .
Half Life
The plasma half-life of allopurinol is 1-2 hours, due to its rapid renal clearance .
Clearance
Since allopurinol and its metabolites are mainly eliminated by the kidney, accumulation of this drug can occur in patients with renal dysfunction or failure, and the dose of allopurinol should, therefore, be reduced. With a creatinine clearance of 10 to 20 mL/min, a daily dosage of 200 mg of allopurinol is suitable. When the creatinine clearance is less than 10 mL/min, the daily dosage should not be higher than 100 mg. With severe renal impairment (creatinine clearance measured at less than 3 mL/min) a longer interval between doses may be required .
Elimination Route
Approximately 80% of orally ingested allopurinol is found excreted in the urine as various metabolites . About 20% of ingested allopurinol is excreted in the feces .
Pregnancy & Breastfeeding use
Sufficient clinical data is not available. This drug should be used during pregnancy only if clearly indicated. Allopurinol has been found in breast milk, caution should be exercised when Allopurinol is administered to a lactating mother.
Contraindication
Patients who have developed a severe reaction to allopurinol should not be restarted the drug. Allopurinol should be withdrawn immediately when a skin rash or other evidence or sensitivity occurs. Dosage reduction should be considered in the presence of severe hepatic or renal disorder.
Acute Overdose
Over dosage may cause diarrhea, abdominal pain and neurotoxicity.
Storage Condition
Protect from light & keep in a cool and dry place. Keep out of reach of children.
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