Allopurinol is a medication used to lower uric acid levels in the blood. Its primary mechanism of action is to inhibit xanthine oxidase, thereby reducing the production of uric acid. This drug is commonly used to treat gout attacks, hyperuricemia, and to prevent uric acid crystal deposition caused by chemotherapy or leukemia. Its pharmacological properties allow for long-term regulation of uric acid balance in the body, slowing joint destruction and the formation of kidney stones.
This medication must be combined with dietary control and adequate hydration to achieve optimal therapeutic effects. Patients should regularly monitor blood uric acid levels and renal function to ensure safe treatment. Since the drug takes several weeks to become effective, patients must follow their physician’s instructions to complete the full course and should not stop medication on their own even if symptoms improve.
Different countries or regions may use various brand names, but the generic component is always Allopurinol. The medication is available in tablet and suspension forms. The common adult dosage ranges from 100 mg to 800 mg daily, adjusted according to renal function and disease severity.
Allopurinol is classified as a xanthine oxidase inhibitor, a specialized medication for treating metabolic disorders. This class of drugs directly blocks uric acid production pathways, unlike drugs that only promote uric acid excretion. Its chemical structure belongs to the thioamide compounds, which selectively inhibit specific enzymes.
This class of drugs offers long-term control advantages in treating chronic hyperuricemia but carries risks such as allergic reactions. The classification information is included in drug safety assessments, and physicians will choose the most appropriate treatment based on the patient’s medical history.
Main indications include:
This medication is also used for hereditary enzyme deficiency diseases such as Lesch-Nyhan syndrome, but strict adherence to genetic assessment results is required. Physicians may prescribe off-label in special cases, with regular evaluation of risk-benefit ratios.
Mild side effects include:
Serious side effects require immediate discontinuation and medical attention:
Contraindications include:
Black Box Warning: This medication may induce life-threatening allergic reactions. It is recommended to start treatment with a low dose (100 mg/day). Pregnant women should only use it if necessary, and breastfeeding women should evaluate whether to discontinue medication or stop breastfeeding. There are reports that concomitant use with ampicillin increases allergy risk, which requires special attention.
Dose adjustments are necessary when combined with the following drugs:
Avoid combining with corticosteroids such as high-dose prednisone, as it may increase gastrointestinal irritation. During use, avoid excessive intake of high-purine foods (such as organ meats, certain fish), which may reduce efficacy.
The initial adult dose is usually 100-200 mg daily, taken once or twice. The dose is gradually increased every 2-5 weeks to the target dose (not exceeding 600-800 mg per day), with ample water intake to promote uric acid excretion. Patients with renal impairment should have reduced doses, and those with a creatinine clearance below 15 mL/min should discontinue use.
The medication should be swallowed whole and not chewed. It can be taken before or after meals, but taking it at a fixed time can reduce gastrointestinal discomfort. Extended-release formulations can decrease blood concentration fluctuations but must be swallowed whole without crushing. Pediatric doses are calculated based on body weight, typically 0.5-1.5 mg per kilogram per day.
If a dose is missed and more than 4 hours remain before the next scheduled dose, take it immediately and shorten the interval until the next dose. If close to the next dose, skip the missed dose and resume normal schedule the following day. Do not double doses to compensate for missed doses.
For long-term therapy, continued missed doses may lead to rising uric acid levels. It is recommended to set reminders for medication. If missed for more than 3 days, contact healthcare providers immediately for treatment assessment.
Acute overdose may cause:
Seek immediate medical attention for gastric lavage and activated charcoal adsorption. Severe poisoning requires hospitalization. Physicians may use charcoal to reduce absorption, and in severe renal failure, hemodialysis may be necessary. Kidney function and blood chemistry should be monitored daily during the first week after overdose.
Is dietary purine intake restricted while taking Allopurinol?
Yes, patients are advised to control high-purine foods such as organ meats, rich soups, and certain seafood while on Allopurinol. Although the drug reduces uric acid production, dietary management helps improve treatment efficacy and prevents large fluctuations in blood uric acid levels.
Should I stop taking Allopurinol immediately if I develop a rash?
If a rash or other skin reactions occur, discontinue the medication immediately and seek medical evaluation. About 3-5% of patients may experience adverse skin reactions, with a very small number developing severe reactions such as Stevens-Johnson syndrome, which requires medical judgment on whether to permanently discontinue the drug.
Are there precautions when combining Allopurinol with antihypertensive or anticoagulant medications?
Combining with thiazide diuretics or hydralazine may increase the risk of skin reactions; when used with warfarin, it may enhance anticoagulant effects. Patients should regularly monitor drug efficacy and blood parameters and inform their physicians of all medications, including over-the-counter and herbal products.
Is long-term use of Allopurinol safe with regard to liver and kidney function?
It is recommended to monitor liver and renal function every 3-6 months during initial treatment, as long-term use may cause elevated liver enzymes or increased renal burden. Patients with pre-existing liver or kidney conditions should have dose adjustments and more frequent monitoring to ensure safety.
Can patients with G6PD deficiency use Allopurinol?
This medication may trigger hemolytic crises in patients with G6PD deficiency and is contraindicated. Before use, physicians will perform blood tests to confirm whether the patient carries this genetic defect to ensure safe and effective treatment.
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