The pharmacological effect of the drug Allopurinol is to reduce the level of acid saturation and prevent the deposition and proliferation of 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, and oncotherapy during therapeutic fasting.
One way or another, all pharmacological analogues of the aforementioned drug incorporate the chemical compound allopurinol, the difference between them lies in the various composite related 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, possess urostatic qualities, which are based more on the ability to destroy the xanthine oxidase protein, which leads to a decrease in the accumulation of uric acid and helps to dissolve urates.
Pharmacokinetics
The drug is absorbed in the upper esophagus in a short time. After internal use, the drug appears in blood plasma after half an hour or 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 bind to proteins in the plasma. The amount of its discrepancy is in the range of 1.3 l / kg.
The drug rapidly (plasma half-life of two hours) conducts oxidation 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 stage, gradual accumulation may occur at the beginning of the cure until equilibrium saturation is reached. In patients with good kidney function, the average concentration is five to ten mg / l after taking a dose. "Allopurinol" is excreted mainly by the kidneys, while less than 10% of the substance is excreted in unmodified form. About 20% comes with feces. The active substance is excreted in the urine in an unmodified form after tubular reabsorption.
The instruction for the use of Allopurinol tablets (EGIS, Teva, Nycomed, etc.), reviews of which are positive, states that pathologies of the kidneys lead to an increase in the half-life of oxypurinol, for this reason, patients with renal failure should follow dose advice.
Indications
Reviews and instructions for use of "Allopurinol" in tablets recommend taking:
- Patients over the age of 18. Treatment of absolutely all forms of hyperuricemia that are not controlled by proper nutrition, with an amount of uric acid in the range of five hundred and fifty micromol / l or more; diseases stimulated by an increase in the amount of uric acid, in particular gout, urate nephropathy and urate urolithiasis; secondary hyperuricemia of various occurrences; primary and secondary hyperuricemia in various hemoblastoses.
- Children and adolescents with a body weight of more than 15 kilograms. Secondary hyperuricemia of various occurrences; urate nephropathy, resulting from a cure for blood cancer; Lesch-Nihan disease and a lack of adenine phosphoribosyl transferase.
- Children and adolescents weighing more than 45 kilograms. Secondary hyperuricemia of various occurrences; urate nephropathy, resulting from a cure for blood disease; congenital enzymatic deficiency, in particular Lesch-Nihan dysgenitalism and deficiency 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.
When creatinine clearance is less than 20 ml / min, 300 mg tablets are not used.
How to use?
The daily portion is determined personally in connection with the degree of concentration of uric acid. In order to reduce the risk of secondary reactions, therapy should be started with 100 mg once a day and increase the dose only if the concentration of uric acid is not lowered enough.
The instructions for use with "Allopurinol" (300 mg) indicate the following course:
- in mild conditions - from 0.1 g to 0.2 g per day;
- in moderately serious conditions - from 0.3 g to 0.6 g per day;
- in 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 once).
When calculating the dose of a substance per patient’s body weight, use a dose of 2-10 mg / kg.
Children and teens. The daily portion is 0.01 g / kg body weight, divided into three uses. The largest daily portion is 0.4 mg. Consume 0.1 g tablets.
Mature age. Due to the lack of specific information regarding the use of the drug in this category of patients, it is recommended to use the lowest therapeutically reasoned doses. The likelihood of pathology of kidney function in elderly patients must be taken into account.
Pathology of the kidneys. Since the drug and its metabolites are excreted by the kidneys, with the pathology of their function, an overdose is likely if the portion is not properly selected.
In severe pathology of renal function, the maximum daily portion is 0.1 g. A single dose of 0.1 g is acceptable with an interval of more than days (every couple of days).
Patients with liver pathology.
Patients with liver disease should be prescribed the lowest dose. At the beginning of treatment, it is recommended to periodically monitor the characteristics of functional liver samples.
Tablets of 0.3 g do not need to be prescribed to these patients because of the high content of a functioning element.
Tablets must be taken after meals without chewing, along with plenty of water.
The duration of treatment depends on the course of the disease. In order to prevent the creation of oxalate and urate stones, and in primary hyperuricemia and gout, in most cases, long-term therapy should be used. In secondary hyperuricemia, a short course is recommended depending on the increase in uric acid levels.
Overdose
Even after taking a single dose of twenty grams, such symptoms as vomiting, nausea, diarrhea and dizziness were sometimes observed. In other cases, a serving of 22.5 g did not produce undesirable results. After prolonged administration of 0.2-0.4 g per day, patients with impaired renal function described severe signs of intoxication (dermatological reactions, fever, hepatitis, eosinophilia and complications of renal failure). With an overdose, the dynamics of xanthine oxidase is significantly suppressed, but only in the case of the combined use of 6-mercaptopurine and azathioprine, the action of the substance is accompanied by significant complications.
According to the instructions for use, if an overdose is suspected, the patient needs to rinse the stomach, provoke nausea or use activated charcoal and sodium phosphate.
Adverse reactions
In the instructions for use of "Allopurinol" side effects are as follows.
At the beginning of therapy, instant gout attacks may appear.
Manifestations of secondary reactions are more often in the presence of renal and / or liver failure, or when used in combination with ampicillin or amoxicillin.
Dermatology: Stevens-Johnson syndrome, toxic epidermal necrolysis; baldness, furunculosis, Quincke's edema, hair depigmentation. The most common dermatological reactions (approximately 4%) appear during any period of therapy and can be expressed as a rash. When these reactions appear, the drug should be interrupted immediately. After reducing the symptoms, you can prescribe a medication in low doses (for example, 50 mg per day). If necessary, this dose can be increased over time. With 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 negatively affect health (reversible increase in transaminases and alkaline phosphatase); cholangitis and xanthine stones; anaphylactic shock.
Liver: liver function pathologies from asymptomatic increase in liver function indices to hepatitis (including death of the liver and granulomatous hepatitis).
Alimentary tract: vomiting, nausea, diarrhea; hemathemesis, steatorrhea, stomatitis.
Blood: severe bone marrow pathologies are extremely rare, especially in patients with renal failure; very rarely there are changes in blood counts, true red blood cell aplasia.
Nervous system: ataxia, peripheral disease, digestive upset sensation, coma, migraine, neuropathy, stupor, dizziness, lethargy, numbness.
Cardiovascular system: bradycardia, arterial hypertension.
Interaction with other drugs
Allopurinol delays the withdrawal of probenecid. The effectiveness of the drug decreases with the use of substances capable of excreting uric acid.
The simultaneous use of "Allopurinol" and "Captopril" can increase the risk of dermatological reactions, especially in chronic kidney diseases.
The effect of anticoagulants (coumarin) may increase, for this reason a more frequent control of blood coagulability is necessary, as well as a reduction in the dose of coumarin derivatives.
In the pathology of renal function, especially when using drugs together, the hypoglycemic effect of chlorpropamide can 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, theophylline level in plasma should be monitored.
When using drugs with cytostatics, a change in the composition of the blood occurs more often than with a single injection 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 of this, a similar 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 the plasma can increase - an increase in the severity of secondary reactions to cyclosporin is permissible.
The drug contributes to the accumulation of iron in the liver cells. The intake of iron-containing medications should be reduced.
"Allopurinol" can lead to increased severity of minor reactions of single pharmaceuticals, in particular when used simultaneously with captopril, the risk of dermatological reactions may increase, especially with constant renal failure.
Analogs
Analogues of the drug are no less effective than the tool 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
Available in tablets, regulates the processes of exchange of uroacid. The main indication for use is gout or gouty arthritis. While taking this drug, an exacerbation of the inflammatory process and dissolution of stones in the bladder are possible with a further exit. Therefore, during treatment with Purinol, abundant water intake is recommended.
Allopurinol-EGIS
The most effective drug in terms of reducing the amount of uric acid with 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 exacerbation of gout, therefore, "Colchicine" is recommended for elderly and patients with renal pathology. It is also prescribed during the treatment of gout and kidney stone pathology.
"Allopurinol Nycomed"
It is used as a drug that prevents the formation and proliferation of stones in the urea and accelerates 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 also, 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.
"Ziloric"
A drug whose pharmacological effect is to reduce the overall level of urate in the body and prevent its deposition in organs. The drug, thanks to the 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 "Sanfipurolom" it is recommended to use up to two liters of fluid per day.
Therapy with 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 performed exclusively by the attending physician.
So, the article describes the instructions for use of "Allopurinol" 100 and 300 mg.