The pharmacological action of the medical preparation "Allopurinol" is to reduce the level of acid saturation and prevent the deposition and growth of the so-called urates, due to the influence on the mechanism of formation of uric acid in the body. According to the instructions for use of "Allopurinol-EGIS" 100 and 300 mg, as well as other manufacturers, the main indications for prescribing the drug include prevention and therapeutic treatment of gout (with the exception of the period of exacerbation and inflammation), urolithiasis in the kidneys, oncotherapy during therapeutic fasting.
All pharmacological analogues of the above drug one way or another contain the chemical compound allopurinol, the difference between them lies in various constituent accompanying components, which in turn affects the effect in terms of a more concentrated or mild effect on the body. Naturally, the difference in the components directly affects the price of drugs.
Pharmacodynamics
"Allopurinol" and its main metabolite oxypurinol disrupt the biosynthesis of uric acid, have urostatic properties, which are based more on the ability to destroy the protein xanthine oxidase, which leads to a reduction in the accumulation of uric acid and promotes the dissolution of urates.
Pharmacokinetics
The drug is absorbed in the upper esophagus in a short time. After internal use, the drug appears in the blood plasma after half an hour to an hour. The bioavailability of the substance is in the range of 67-90%.
Peak saturation is reached after an hour and a half. The drug practically does not combine with proteins in the plasma. The amount of its discrepancy is within the figure of 1.3 l/kg.
The agent rapidly (half-life from blood plasma is two hours) oxidizes through xanthine oxidase and aldehyde oxidase to oxypurinol, which is also considered a strong inhibitor of xanthine oxidase, but the half-life of the metabolite can last from thirteen to thirty hours. Given the long half-life, there may be a gradual build-up at the onset of cure until equilibrium saturation is reached. In patients with good kidney function, the average concentration is five to ten mg / l after a dose. "Allopurinol" is excreted mainly by the kidneys, while less than 10% of the substance is excreted in unmodified form. Approximately 20% is excreted in the feces. The active substance is excreted in the urine in an unmodified form after tubular reabsorption.
Instructions for usetablets "Allopurinol" ("EGIS", "Teva", "Nycomed", etc.), reviews of which are positive, says that pathologies of the kidneys lead to an increase in the half-life of oxypurinol, for this reason, patients with renal failure should follow the advice regarding doses.
Indications
Reviews and instructions for the use of "Allopurinol" in tablets recommend taking:
Patients over 18 years of age. Treatment of absolutely all forms of hyperuricemia that are not controlled by proper nutrition, with the amount of uric acid in the range of five hundred and fifty micromol / l and more; diseases stimulated by an increase in the amount of uric acid, in particular gout, urate nephropathy and urate urolithiasis; secondary hyperuricemia of various origins; primary and secondary hyperuricemia in various hemoblastoses
Children and adolescents weighing over 15 kilograms. Secondary hyperuricemia of various origins; urate nephropathy, which appeared as a result of a cure for blood cancer; Lesch-Nyhan disease and deficiency of adenine phosphoribosyl transferase
Children and adolescents weighing over 45 kilograms. Secondary hyperuricemia of various origins; urate nephropathy, which appeared as a result of a cure for a blood disease; congenital enzyme deficiency, in particular Lesch-Nyhan dysgenitalism and lack of adenine phosphoribosyltransferase
Contraindications
High susceptibility to "Allopurinol" or any of the ingredients of the drug.
Severe pathologies of kidney function (creatinine clearance less than 2 ml/min) and liver.
If creatinine clearance is less than 20 ml/min, do not use 300 mg tablets.
How to use?
Daily portion is determined individually in connection with the degree of concentration of uric acid. To reduce the risk of secondary reactions, therapy should be initiated at 100 mg once daily and increased only if uric acid levels are not sufficiently reduced.
In the instructions for use for "Allopurinol" (300 mg) the following course is indicated:
- for mild conditions, 0.1 g to 0.2 g per day;
- for moderately serious conditions - from 0.3 g to 0.6 g per day;
- for serious conditions - from 0.7 g to 0.9 g per day.
If the daily portion exceeds 300 mg, it must be divided into several doses (no more than 300 mg at a time).
When calculating the dose of a substance per patient's body weight, use doses of 2-10 mg/kg.
Children and teenagers. The daily portion is 0.01 g/kg of body weight, divided into three doses. The largest daily serving is 0.4 mg. Use 0.1g tablets
Mature age. Due to the lack of special information regarding the use of the drug in this category of patients, it is recommended to use the lowest therapeutically reasoned doses. Must be taken intoattention to the probability of pathology of kidney function in elderly patients.
Pathology of the kidneys. Since the drug and its metabolites are excreted by the kidneys, if their function is pathological, an overdose is likely if the portion is not selected properly.
In severe kidney disease, the maximum daily dose is 0.1 g. A single dose of 0.1 g is acceptable with an interval of more than a day (every couple of days).
Patients with liver pathology.
Patients with liver disease should be prescribed the lowest possible doses. Periodic monitoring of liver function tests is recommended at the start of treatment.
Pills of 0.3 g should not be prescribed to these patients due to the high content of the functioning element.
Pills should be taken after meals, without chewing, along with plenty of water.
The duration of the course of treatment depends on the course of the disease. In order to prevent the formation of oxalate and urate stones and in primary hyperuricemia and gout, long-term therapy should be used in most cases. For secondary hyperuricemia, a short course is recommended depending on the rise in uric acid levels.
Overdose
Already after taking a single dose of twenty grams, symptoms such as vomiting, nausea, diarrhea and dizziness were sometimes observed. In other cases, a serving of 22.5 g did not cause undesirable results. Afterlong-term intake of 0.2-0.4 g per day, patients with impaired renal function described severe signs of intoxication (dermatological reactions, fever, hepatitis, eosinophilia and complication of renal failure). In case of an overdose, the dynamics of xanthine oxidase is significantly suppressed, but only in the case of the complex use of 6-mercaptopurine and azathioprine, the effect of the substance is accompanied by significant complications.
According to the instructions for use, if an overdose is suspected, the patient should be gastric lavage, provoke nausea, or use activated charcoal and sodium phosphate.
Adverse reactions
In the instructions for the use of Allopurinol, the side effects are as follows.
At the beginning of therapy, instant attacks of gout may occur.
Minor reactions are more common in the presence of renal and/or hepatic insufficiency or when combined with ampicillin or amoxicillin.
Dermatology: Stevens-Johnson syndrome, toxic epidermal necrolysis; alopecia, furunculosis, angioedema, hair depigmentation. The most common dermatological reactions (approximately 4%) occur during any period of therapy and can be expressed as a rash. If these reactions occur, the drug should be discontinued immediately. Even after the symptoms decrease, you can prescribe a medication in low doses (for example, 50 mg per day). If necessary, thisthe dose can be increased over time. In the event of a secondary manifestation of a dermatological rash, the substance should be discontinued, as severe hypersensitivity phenomena may occur.
Immune system: delayed-type hypersensitivity reactions accompanied by fever, dermatological rashes and other pathologies that adversely affect he alth (reversible increase in transaminases and alkaline phosphatase); cholangitis and xanthine stones; anaphylactic shock.
Liver: Liver function abnormalities ranging from asymptomatic enlargement of liver function tests to hepatitis (including liver death and granulomatous hepatitis).
Digestive tract: vomiting, nausea, diarrhea; hematemesis, steatorrhea, stomatitis.
Blood: Severe bone marrow pathology is extremely rare, especially in patients with renal insufficiency; very rarely there are changes in blood counts, true erythrocyte aplasia.
Nervous system: ataxia, peripheral disease, gustatory disturbance, coma, migraine, neuropathy, torpor, dizziness, lethargy, numbness.
Cardiovascular system: bradycardia, arterial hypertension.
Interaction with other drugs
"Allopurinol" delays the withdrawal of probenecid. The effectiveness of the drug is reduced when using substances that can remove uric acid.
Simultaneous use of "Allopurinol" and "Captopril" may increase the risk of dermatological reactions, especially in chronickidney disease.
The effect of anticoagulants (coumarin) may increase, for this reason more frequent monitoring of blood clotting is necessary, as well as a reduction in the dose of coumarin derivatives.
In pathology of kidney function, especially with the combined use of drugs, the hypoglycemic effect of chlorpropamide may be prolonged, which requires a dose reduction.
In significant portions, the drug inhibits theophylline metabolism, for this reason, at the beginning of Allopurinol therapy or with an increase in its dose, plasma theophylline levels should be monitored.
When using drugs with cytostatics, a change in the composition of the blood occurs more often than with a single administration of active substances. For this reason, blood counts must be monitored at short intervals.
With the complex use of the drug with vidarabine, fifty percent of the final plasma is prolonged, as a result, such a combination must be used with caution in order to avoid an increase in the severity of secondary reactions. When using a medicinal substance, the concentration of cyclosporine in plasma may increase - an increase in the severity of secondary reactions to cyclosporine is acceptable.
The drug promotes the accumulation of iron in the liver cells. Iron supplementation should be reduced.
"Allopurinol" can lead to an increase in the severity of minor reactions of single pharmaceuticals, in particular when used simultaneously with captopril threatthe occurrence of dermatological reactions may increase, especially in permanent renal failure.
Analogues
Analogues of the drug are no less effective than the remedy itself. The price of such drugs is quite affordable. Among the most commonly used analogues of Allopurinol, the instructions for use and reviews of which are similar to the described drug, you can stop at Purinol, Sanfipurol, Zilorik.
Purinol
Produced in tablets, regulates the exchange of uric acid. The main indication for use is gout or gouty arthritis. While taking this drug, an exacerbation of the inflammatory process and the dissolution of stones in the bladder with a further exit is possible. Therefore, during therapy with Purinol, an abundant intake of water is recommended.
Allopurinol-EGIS
The most effective drug in terms of reducing the amount of uric acid in similar diagnostic indications is, according to the instructions for use, "Allopurinol-EGIS". In the reviews, both patients and doctors confirm that the drug is quite aggressive and can provoke an exacerbation of gout, so Colchicine is recommended for the elderly and patients with renal pathology. It is also prescribed for the treatment of gout and kidney stones.
Allopurinol Nycomed
Used as a drug that preventsthe formation and growth of stones in the urea and accelerating their excretion in the urine. A characteristic feature of this drug is its rapid (one or two hours) absorption and complete absorption from the gastrointestinal tract.
Allopurinol Teva
Recommended for gout, oncopathology, and, importantly, for the regulation of purine metabolism in children. The drug is quite concentrated, so it is allowed to divide the tablet into several parts.
Zilorik
A drug whose pharmacological action is to reduce the overall level of urate in the body and prevent its deposition in organs. The drug, due to its accompanying components, practically does not cause side effects, but is not prescribed for individual intolerance.
Sanfipurol
A drug that regulates the metabolic process of uric acid. It is used as an analogue for gout, kidney stones, nephropathy, leukemia. During therapy with Sanfipurol, it is recommended to consume up to two liters of fluid per day.
Therapy with the use of "Allopurinol" and its analogues begins, as a rule, with small daily doses and is contraindicated during pregnancy and lactation. It should be noted that the appointment and dosage of the above drugs is made exclusively by the attending physician.
So, the article discussesinstructions for use "Allopurinol" 100 and 300 mg.
