Allopurinol

Allopurinol belongs to the category of drugs that suppress the formation of uric acid. It is an anti-gout medication that inhibits the binding of uric acid and its salts inside the body.

The drug is able to slow down the activity of the xanthine oxidase enzyme, which is a participant in the transformation processes of hypoxanthine / xanthine and xanthine / uric acid. As a result of such interactions, the serum value of urates decreases, which prevents their deposition inside the kidneys and tissues. [1]

Indications Allopurinol

In adults, the medication is used for such violations:

• hyperuricemia (with a serum uric acid reading of 500+ μmol / l), which cannot be controlled by diet;
• pathologies associated with an increase in the blood values of uric acid (especially urate nephropathy, gout and urate urolithiasis);
• secondary type hyperuricemia of a different nature (also psoriasis);
• associated with various hemoblastoses (lymphosarcoma, active form of leukemia and chronic myeloid leukemia), primary or secondary hyperuricemia;
• cytotoxic treatment for diseases of myeloproliferative and neoplastic nature.

Children are prescribed for such diseases:

• urate form of nephropathy, which developed during the treatment of leukemia;
• secondary type hyperuricemia of various origins;
• congenital enzymatic insufficiency (including complete or partial deficiency of HGFT; Lesch-Nien syndrome) and congenital deficiency of ATPT.

Release form

The release of the drug substance is realized in the form of tablets - 10 pieces inside the cell package. There are 5 such packages inside the box.

Pharmacodynamics

Inside the body, allopurinol is converted to oxypurinol, which prevents the formation of uric acid, but its activity is weaker than that of allopurinol.

Pharmacokinetics

After oral administration, the drug is fully absorbed and at a high rate. There is almost no absorption inside the stomach, absorption takes place inside the duodenum and in the upper region of the small intestine.

Metabolic processes lead to the formation of the main drug-active metabolic component of oxypurinol. Indicators Cmax oxypurinol are noted after 3-4 hours; the rate of formation is associated with the rate and degree of personal presystemic exchange processes. Oxypurinol with allopurinol are almost not involved in protein synthesis.

The plasma half-life of allopurinol is approximately 40 minutes, and oxypurinol is 17-21 hours. 80% of both elements are excreted through the kidneys; intestines are excreted 20%. In individuals with impaired renal function, the term oxypurinol half-life is prolonged.

Dosing and administration

Allopurinol must be taken orally after a meal; the tablets are swallowed whole with plain water. You cannot chew the tablets. During therapy, the patient needs to take a lot of fluids in order to maintain a stable diuresis function. Sometimes urine alkalinization is done to improve uric acid excretion.

The dosage sizes and the duration of treatment are selected by the treating doctor personally, taking into account the severity of the pathology and the clinical situation.

During the selection of the daily dosage of the medication, it is imperative to take into account the plasma indicator of uric acid. The patient can take 0.1-0.3 g of medication per day. Dosage adjustment is performed 1-fold in 1 or 3 weeks. A maximum of 0.8 g of the drug is allowed per day.

• Application for children

It is forbidden to use the medicine in persons under 3 years of age.

Use Allopurinol during pregnancy

There is no information available regarding the use of Allopurinol during pregnancy. Since the active element of the drug affects the metabolic processes of purine, and there is no information regarding the potential risks to humans, it is prohibited to prescribe the drug to pregnant women.

The medication is excreted in breast milk, which is why it is not used for hepatitis B. It is necessary to refuse breastfeeding during therapy.

Contraindications

The main contraindications:

• severe intolerance to allopurinol or other elements of the medication;
• severe hepatic / renal dysfunction (CC values below 2 ml per minute);
• active stage of a gouty attack.

Side effects Allopurinol

Among the side signs:

• metabolic disorders: at the initial stage of therapy, an active gouty attack may develop, which is associated with the mobilization of uric acid in the area of gouty nodules and other depots;
• problems with liver and gastrointestinal tract function: vomiting, curable increase in blood levels of alkaline phosphatase and transaminases, stomatitis, nausea, hepatitis, diarrhea and active form of cholangitis;
• disorders of hematopoietic processes: leukocytosis, leukopenia or eosinophilia. Severe bone marrow damage (agranulocytosis, thrombocytopenia and aplastic anemia), especially in people with impaired renal function;
• symptoms associated with the activity of the CVS: increased blood pressure and bradycardia;
• lesions in the central nervous system: drowsiness, cephalalgia, fatigue, dizziness, ataxia, weakness, convulsions and neuropathy, as well as myalgia, depression, paresthesia and paresis, as well as a peripheral form of neuritis;
• manifestations associated with the sensory organs: cataracts, taste or visual disturbance;
• disorders of urinary processes: uremia, tubulointerstitial nephritis, accompanied by infiltration of lymphocytes, xanthogenic calculi and hematuria;
• signs of allergies: urticaria, heating elements, chills, MEE, pruritus, erythema, fever and arthralgia;
• others: impotence, diabetes mellitus, baldness and gynecomastia.

In persons with impaired renal function, when using a standard dosage, vasculitis with epidermal changes may occur; later this process can go to the liver with kidneys. If vasculitis develops, you should immediately stop taking Allopurinol.

Overdose

Sometimes people who do not have renal dysfunctions who take 20 g of medication per day experience vomiting, stool disorders, nausea and dizziness.

Long-term use of drugs in people with renal dysfunction sometimes causes eosinophilia, hyperthermia, epidermal rash and exacerbation of renal pathologies. There is no antidote for the drug, which is why symptomatic actions must be carried out in case of poisoning.

Interactions with other drugs

The effect of the medication is weakened when using drugs with a uricosuric effect (probenecid, sulfinpyrazone and benzbromarone), as well as with large doses of salicylates.

Allopurinol is able to slow down the activity of xanthine oxidase, as well as the metabolic processes of purine derivatives (among them mercaptopurine and azathioprine), which is why their standard serving should be reduced by 50-75%.

Large dosages of the drug reduce the rate of excretion of probenecid and inhibit the metabolism of theophylline.

The combination of the drug with chlorpropamide requires a decrease in the dosage of the latter.

The introduction of Allopurinol in combination with coumarin anticoagulants requires a decrease in their portion. In addition, you need to regularly monitor blood clotting rates.

The use of the medication together with captopril increases the likelihood of developing epidermal symptoms, especially if the patient has CRF.

Combination with cytostatics can provoke an increase in the frequency of changes in blood parameters (in comparison with the separate use of these medicines), which is why it is recommended to perform a blood test more often than usual.

Combining the drug with amoxicillin and ampicillin increases the likelihood of developing signs of allergy.

Storage conditions

Allopurinol must be kept out of the reach of children. Temperature values - no more than 25 ° С.

Shelf life

Allopurinol can be used within a 5-year term from the date of manufacture of the drug substance.

Analogs

An analogue of the drug is the drug Allohexal.