Allopurinol: What is it? Uses, Precautions, Administration and Side Effects

It is used to treat gout caused by excessive levels of uric acid in the blood (hyperuricemia).

It is an inhibitor of xanthine oxidase and is similar to febuxostat (Uric Acid).

Uric acid is a byproduct of the breakdown of certain proteins (purines) in the body by enzymes called xanthine oxidases. Hyperuricemia occurs when the body produces more uric acid than it can eliminate.

Uric acid forms crystals in the joints (gouty arthritis) and tissues, causing inflammation and pain. Elevated levels of uric acid in the blood can also cause kidney disease and kidney stones.

Allopurinol prevents the production of uric acid by blocking the activity of enzymes that convert purines into uric acid.

Uric acid levels generally begin to decrease within 2-3 days after the start of treatment and return to their original levels within 7-10 days after the suspension of Allopurinol.

Several months of treatment may pass before the gout attacks are controlled.


  • Hypersensitivity to Allopurinol


  • Suspend the first sign of allergic reactions (first sign of rash, vasculitis or Stevens-Johnson syndrome).
  • Use caution when administering other medications known to cause myelosuppression.
  • Hepatotoxicity (reversible) reported.
  • Do not use for the treatment of asymptomatic hyperuricemia.
  • Use with caution in renal failure.
  • Risk of increased hypersensitivity in patients treated with angiotensin-converting enzyme (ACE) inhibitors.
  • When taken with amoxicillin or ampicillin , it can increase the risk of rash.
  • During concomitant treatment, reduce the doses of azathioprine and mercaptopurine to 25-33% of normal.
  • The risk of hypersensitivity may increase with the concomitant administration of thiazides.

Maintain the necessary fluid intake to produce a urine production of at least 2 liters / day in adults


The recommended dose ranges from 100 mg to 800 mg per day in 1 to 3 divided doses taken after meals, depending on the condition being treated.

Store at room temperature in a dry place and keep out of the reach of children.

Side effects

Check with your doctor immediately if you experience any of the following side effects:

More common

  • Pain in the ankle joint, knee or big toe.
  • Rigidity or swelling in the joints.
  • Eruption.
  • Eruption with flat lesions or small raised lesions on the skin.


  • Abdominal or stomach pain
  • Agitation.
  • Smell of breath similar to ammonia.
  • Anxiety.
  • Blistering, peeling or loosening of the skin.
  • Blood in the urine or in the stool.
  • Bleeding nose
  • Skin blue or pale.
  • Hematomas.
  • Changes in skin color.
  • Pain or discomfort in the chest.
  • Pain in the chest, possibly moving to the left arm, neck or shoulder.
  • Shaking chills.
  • Clay stools.
  • Cough with blood.
  • Cracks in the skin.
  • Dark urine.
  • Decrease in urine production.
  • Depression.
  • Diarrhea.
  • Difficulty breathing.
  • Dizziness
  • Drowsiness.
  • Dry mouth.
  • Feeling faint, dizzy or light-headed.
  • Feeling of heat or heat.
  • Fever.
  • Redness or redness of the skin, especially on the face and neck.
  • General feeling of discomfort or illness.
  • Headache.
  • Hostility.
  • Incoherent speech.
  • Increased urination
  • Irritability.
  • Itch.
  • Pain in the joints or muscles.
  • Large, flat, blue or violet spots on the skin.
  • Lethargy.
  • Stool light colored.
  • Loss of appetite
  • Loss of body heat.
  • Low back pain or back pain
  • Metallic flavor.
  • Muscular weakness.
  • Nausea or vomiting
  • Pain, tenderness or swelling of the foot or leg.
  • Red or purple spots on the skin.
  • Rapid weight gain
  • Eruption.
  • Red and irritated eyes.
  • Red and swollen skin.
  • Pain and fullness of the upper right abdomen or stomach.
  • Scaly skin.
  • Convulsions
  • Severe stomach pain.
  • Difficulty breathing.
  • Slow or irregular heartbeat.
  • Stupor.
  • Sweating
  • Swelling of the face, ankles, hands or lower legs.
  • Swollen or painful glands
  • However.
  • Bleeding or unusual bruising
  • Unusual weight gain or loss
  • Vomiting blood or material that looks like coffee grounds.
  • Wheezing
  • Yellow eyes or skin

These side effects may go away during treatment as your body adjusts to the medication.