Allopurinol is used to treat gout that is caused by too much uric acid in the blood. Allopurinol works by making the body produce less uric acid, and is only effective after regular use for a few months. It will not cure gout or stop an attack that has already started. Allopurinol is also used to treat other medical problems including certain kinds of kidney stones or other kidney problems.
Be sure to tell your doctor of any allergies you have whether it is to medication or food, preservatives, or dyes. Tell your doctor if you are breastfeeding, as Allopurinol can be passed through breast milk. Also, tell your doctor of any other medications you are taking, including vitamins and supplements, and any medical conditions you may have.
It is very important that you take this medicine exactly as your doctor tells you to. Do not take more or less medicine than directed, and don’t stop Allopuinol without discussing it with your doctor first. Remember it takes a few months before you notice Allopurinol working, and that it will only work for as long as you take it.
If you miss a dose of this medicine, take it as soon as you remember, unless it is almost time for your next dose. Do NOT double doses.
Stop taking Allopurinol and check with your doctor immediately if any of the following side effects occur: skin rash or sores, hives, or itching; black, tarry stools; bleeding sores on lips; blood in urine or stools; chills, fever, muscle aches or pains, nausea, or vomiting-especially if occurring with or shortly after a skin rash; difficult or painful urination; pinpoint red spots on skin; redness, tenderness, burning, or peeling of skin; red and/or irritated eyes; red, thickened, or scaly skin; shortness of breath, troubled breathing, tightness in chest, or wheezing; sores, ulcers, or white spots in mouth or on lips; sore throat and fever; sudden decrease in amount of urine; swelling in upper abdominal (stomach) area; swelling of face, fingers, feet, or lower legs; swollen and/or painful glands; unusual bleeding or bruising; unusual tiredness or weakness; weight gain; or yellow eyes or skin.
Allopurinol is known chemically as 1,5-dihydro-4H-pyrazolo [3,4-d]pyrimidin-4-one. It is a xanthine oxidase inhibitor which is administered orally and intravenously. It is a white amorphous mass with a molecular weight of 158.09 and molecular formula C 5 H 3 N 4 NaO.Each scored white tablet contains 100 mg allopurinol and the inactive ingredients lactose, magnesium stearate, potato starch, and povidone. Each scored peach tablet contains 300 mg allopurinol and the inactive ingredients corn starch, FD&C Yellow No. 6 Lake, lactose, magnesium stearate, and povidone. Its solubility in water at 37°C is 80.0 mg/dl and is greater in an alkaline solution.
It has the structural formula below.