Drug title

Zyloprim (Allopurinol) 

Pharmacological action

A remedy which interferes with the synthesis of uric acid. It is a structural analog of hypoxanthine. It inhibits xanthine oxidase enzyme, which is involved in conversion of hypoxanthine into xanthine and xanthine into uric acid. This is due to a decrease in the concentration of uric acid and its salts in the liquid media of the body and urine, which helps to dissolve existing urate deposits and prevents their formation in the tissues and kidneys. Zyloprim (Allopurinol)  administration increases urinary excretion of hypoxanthine and xanthine.

Pharmacokinetics

After oral administration is almost completely (90%) absorbed from the gastrointestinal tract. It is metabolized to form alloxanthine, which retains the ability to inhibit xanthine oxidase for quite a long time. Cmax of allopurinol in blood plasma is reached on average in 1.5 hours, alloxanthin - in 4.5 hours after a single dose.

T1/2 of allopurinol is 1-2 hours, of alloxantine about 15 hours. About 20% of the dose taken is excreted through the intestine, the rest through the kidneys.

Contraindications for use

Severe liver and/or renal dysfunction, pregnancy, lactation, hypersensitivity to allopurinol.

Administration during pregnancy and lactation

It is contraindicated for use during pregnancy and lactation (breast-feeding).

Administration in patients with liver dysfunction

Contraindication: Severe hepatic impairment. Allopurinol should be used with caution in patients with liver dysfunction (dose reduction is required).

Administration in impaired renal function

Contraindication: severe renal dysfunction. Allopurinol should be used with caution in patients with impaired renal function (dose reduction is required).

Administration in children

It is used in children only in malignant tumors (especially leukemia), as well as in some enzyme disorders (Lesch-Nichen syndrome).

Regimen of dosage is adjusted individually, under control of concentration of urate and uric acid in blood and urine: for children under 15 years old it is 10-20 mg/kg/day or 100-400 mg/day.

Zyloprim (Allopurinol) active substance indications

Treatment and prevention of gout and hyperuricaemia of various genesis (including in combination with nephrolithiasis, renal failure, urate nephropathy). Recurrent mixed oxalate-calcium kidney stones in the presence of hyperuricosuria. Increased formation of urate due to enzyme disorders. Prevention of acute nephropathy in cytostatic and radiation therapy for tumors and leukemia, as well as in complete therapeutic fasting.

Dosing regimen

It is established individually, under control of urate and uric acid concentration in blood and urine. Adults when taken orally - 100-900 mg/day, depending on the severity of the disease. Frequency of intake is 2-4 times per day after meals. In children under 15 years of age 10-20 mg/kg/day or 100-400 mg/day.

Maximal doses: In patients with kidney dysfunction (including those caused by urate nephropathy) the dose is 100 mg/day. The dose may be increased in cases when against the background of the current therapy there are still high concentrations of urate in blood and urine.