Allopurinol is used to treat gout , renal calcium oxalate relief, and prevention of urinary nephropathy when chemotherapy is used. Allopurinol inhibits an enzyme called xanthine oxidase, which produces uric acid in the human body, Allopurinol reduces uric acid levels in the body by reducing production.
In the United States, Allopurinol is sold as Zyloprim, Lopurin. In other countries it is sold as Zyloric, Purinol, aluron, Loric, Puricos, Zylapour, Aloric, Alloril, llanol, No-Uric and Purinase.
The main use of Allopurinol is gout with purpose to reduce uric acid levels. Allopurinol is not used in the treatment of acute gout attacks. It is used in chronic gout and can prevent gout attacks.
- Control of blood uric acid associated with gout, primary or secondary gout may be caused by diseases such as acute or chronic leukemia, polycythemia vera, multiple myeloma and psoriasis occur.
- High levels of blood uric acid from malignant diseases.
- Prevention of uric acid induced nephropathy during cancer chemotherapy .
- Recurrent kidney stones made of Calcium oxalate.
Gout treatment with Allopurinol
Allopurinol is used to treat gout, which is the most painful form of arthritis. It is also used to treat kidney stones.
Different processes in the body are performed by chemicals called the enzyme and act as reactives and catalysts. Xanthine oxidase is one of these enzymes that oxidizes xanthine and hypogonatin and turns it into uric acid then uric acid is excreted in the urine. Gout is caused by excessive uric acid levels and, consequently, high levels of blood acidity.
Therefore, in order to treat or prevent gout, the mechanism that causes the formation of uric acid should be controlled and stopped. This is exactly what Allopurinol is doing.
Allopurinol combines with the xanthine oxidase enzyme and inactivates it, thereby inhibiting the oxidative process of Xanthine and Hypocanthine. Consequently, production of uric acid decreases and prevents the onset of gout. It is useful in preventing gout, but is not capable of treating acute attacks of the disease.
It is a white tablet, each containing 500 mg of Allopurinol and other compounds such as Monostear Stearate, Lactase, and starch. The concentration of this drug may vary with the dose requested.
The dosage of Allopurinol varies according to the severity of the disease and can be taken once daily or divided, but values greater than 300 mg should be given in divided doses.
First, 100 mg once a day after a meal. It is then gradually increased to about 300 mg / day for 1-3 weeks, based on the concentration of uric acid. The usual maintenance dose is 200-600 mg and in acute conditions 700-900 mg per day. Doses greater than 300 mg per day are given in divided doses.
In tumor (neoplasia) and enzyme disorders, daily administration of 10 mg / kg or 400-100 mg / day is recommended.
Dosage of rare cases
Gout acute attacks
Adults: The amount of 100 mg / day is taken by mouth. This is added at a dose of 100 mg at weekly intervals to reach the concentration of serum uric acid to 6 mg per 100 ml. In these cases, the recommended dose should not exceed 800 mg / day.
Adults: The dose of 200 mg / m2 is given in the form of intravenous infusion, which can be given once daily, or divided every 6, 8 or 12 hours. The maximum amount allowed is 600 mg per day.
Children aged 6 to 10 years: 300 mg / day in three divided doses. In children under the age of 6 years, the amount of 150 mg / day is consumed by eating.
Adults: The amount of 800-600 mg / day is taken for 2-3 days in an edible manner. A lot of fluids should be consumed along with medication.
Adults: The amount of 200-300 mg / day is taken in an oral diet. This amount can also be consumed in a split way.
Adults: If the clearance of creatinine is 20-10 ml / min, the amount of 200 mg / day, if less than 10 ml / min, is 100 mg / day, and if less than 3 ml / min, the amount of 100 Mg is taken more than a day in an edible way.
How to take ?
If you miss a dose, take your Allopurinol dose immediately. Never increase the dosage of the drug until the next dose is reached. For patients with renal impairment, the dose should be very low, because in some cases it has been reported to cause kidney damage.
- It is usually taken once daily with water, but if you have any abdominal problems, take it with milk.
- It’s recommended to drink a lot of fluids (2-3 liters) during the treatment with this drug.
- Reduce calcium oxalate, animal protein, sodium, refined sugar, vitamin C , foods rich in oxalate and calcium when taking Allopurinol for kidney stones.
- Avoid alcohol, as alcohol reduces the effectiveness of Allopurinol.
Reported Side effects
This drug should be discontinued if you experience the following symptoms;
- Headache , peripheral neuropathy, neuritis, sensory impairment, drowsiness , fever, indigestion.
- Skin rash, Stevens Johnson syndrome , Thromboembolic epidermis, Baldness, Multivariate erythema, Ichthyosis, Purpura lesions, Dysuria-vesicles, dermatitis, pseudo exammary, itching, hives , onycholysis, lichen planus.
- Cataracts , Retinal disease , Multiple cysts in the nose, Nosebleeds .
- Nausea, vomiting, diarrhea , abdominal pain, frequent, gastritis, dyspepsia, a metallic taste, loss of sense of taste , abdominal pain.
- Renal failure, uremia
- Agranulocytosis, anemia, aplasia, decreased bone marrow activity, leukopenia, pancytopenia, thrombocytopenia, ecchymosis, eosinophilia, leukocytosis.
- Elevated levels of alkaline phosphatase, hepatomegaly, increased bilirubin, obstructive jaundice, granulomatous hepatitis, liver necrosis.
Precautions to take
- Skin rash is most commonly seen in patients who take diuretic drugs or have kidney failure. Rash of allopurinol may occur weeks after discontinuation of the drug.
- The balance of fluid intake and urine output should be followed up. Urine output is at least two liters per day.
- If you have kidney failure, your doctor should reduce your dose of allopurinol at any time.
- Before taking Allopurinol, a complete blood count (CBC) count, serum uric acid concentration, and liver and kidney function should be determined.
- In the first six weeks of treatment with this drug, acute attacks can occur. For prevention, your doctor can administer Colchicine or other anti-inflammatory drugs.
- To minimize the digestive side effects of the drug, it can be taken with food or immediately after a meal. The tablet can be crushed and taken with food or fluids.
80% of the drug is absorbed into the blood after taking the tablet. Allopurinol like uric acid is metabolized by the xanthine oxidase enzyme, which its metabolite (Aluzantin) is an enzyme-inhibitor that has a long half-life. About 70% of the drug is converted to the active metabolite in the first passage from the liver. The half-life of Allopurinol is 1-3 hours and its metabolite half-life is about 15 hours. Renal allopurinol is excreted
Broadly spreads throughout the body, except the brain. Concentration of Allopurinol in the brain is 50% of other parts of the body. Allopurinol and Oxpyrinol do not bind to plasma proteins.
Allopurinol is excreted renally, 7 to 5 percent is excreted unchanged in 6 hours through the urine.It is excreted in the form of Allopurinol, Oxyurinol and Oxypyrinol Ribonucleoside through the kidney. Approximately 70% of this drug is excreted in urine as Oxypyrinol and about 2% within 24-48 hours via feces.
- Patients treated with Allopurinol have reported an increase in serum concentrations of alkaline phosphatase, aspartate aminotransferase (AST) and alanine aminotransferase (ALT).
- Co-administration with Thiazide medications in patients with decreased renal function may increase the risk of hypersensitivity reactions and Excessive Allopurinol production.
- Co-administration use of Azathioprine and Mercaptopurine may increase the toxic effects of these drugs, in particular the reduction of bone marrow activity. If necessary, the concomitant use of these drugs should reduce the amount of azathioprine or mercaptopurine to 25-33% of their usual dosage, and adjust the subsequent dose according to the patient’s response and toxic effects.
- Co-administration use with Cyclophosphamide may increase the risk of bone marrow depletion through an unknown mechanism.
- Allopurinol inhibits the liver microsomal metabolism of Dicoumarol and increases its half-life. Patients taking Allopurinol and dicomarol simultaneously should be monitored for increased anticoagulant effects.
- Taking Allopurinol with ampicillin or amoxicillin increases the risk of developing rash.
- Taking allopurinol at high doses (600 mg / day) with theophylline can reduce the theophylline clearance and increase the plasma levels of theophylline . Plasma levels of the drug should be controlled.
- Since allopurinol or its metabolites may compete with Chlorpropamide in secretion of renal tubes, the condition of patients taking these drugs simultaneously should be monitored for excessive hypoglycaemia .
- Co-administration with co-trimoxazole has been associated with thrombocytopenia.
Patients should be monitored for CBC and platelets.
Pregnancy & lactation
There is no research about the safety on pregnant women, but three reports have stated that no evidence of Allopurinol contraindication in pregnancy. According to the FDA, Allopurinol in Group C drugs i.e potential benefits may warrant use of the drug in pregnant women despite risks.
Due to the release of Allopurinol and Oxypyrinol in breast milk , this drug should be prescribed with caution in lactating women.
Questions & Answers
Q: How long does Allopurinol take to work ?
Answer : The effect of Allopurinol begins 24 to 48 hours after taking, but the peak effect of this drug is 2 to 6 hours later.
Q: Why Allopurinol is used for kidney stones ?
Answer : Renal stones are made of uric acid. Allopurinol decreases blood urea and calcium oxalate stones. Due to the possibility of kidney stones, the co-administration of vitamin C and Allopurinol is not recommended.