Allopurinol is a medication used to lower uric acid levels in the blood and urine, indicated for the treatment of gout and other conditions associated with hyperuricemia.

Indications

• Treatment and prevention of gout.
• Hyperuricemia (elevated uric acid levels in the blood).
• Hyperuricosuria (high uric acid levels in the urine) associated with therapeutic fasting or chemotherapy.

Contraindications

• Severe hepatic or renal impairment.
• Hypersensitivity to allopurinol.

Side Effects

• Gastrointestinal disturbances.
• Hepatic dysfunction.
• Weakness.
• Headache.
• Visual disturbances.
• Impotence.
• Rash, skin redness, itching.
• Changes in blood cell counts.

Drug Interactions

• Concomitant use of allopurinol enhances the effects of coumarin anticoagulants, adenine arabinoside, and hypoglycemic agents (especially in cases of renal dysfunction).
• Uricosuric agents and high doses of salicylates reduce the effectiveness of allopurinol.
• Combined use of allopurinol with cytotoxic agents increases the risk of myelotoxic effects compared to their separate administration.
• Concurrent use of allopurinol with azathioprine or mercaptopurine leads to the accumulation of these drugs in the body. This occurs because allopurinol inhibits xanthine oxidase, an enzyme necessary for the biotransformation of these drugs, slowing their metabolism and excretion.

Overdose

Symptoms: nausea, vomiting, diarrhea, dizziness, oliguria.
Treatment: forced diuresis, hemodialysis, and peritoneal dialysis.