Allopurinol

What is allopurinol?

Allopurinol is used to treat gout (a type of arthritis in which uric acid, a naturally occurring substance in the body, builds up in the joints and causes sudden attacks of redness, swelling, pain, and heat in one or more joints). Allopurinol is also used to treat high levels of uric acid that builds up in the blood as tumors break down in people with certain types of cancer who are being treated with chemotherapy medications. It is also used to treat kidney stones that have come back in people who have high levels of uric acid in their urine. Allopurinol is in a class of medications called xanthine oxidase inhibitors. It works by reducing the production of uric acid in the body. High levels of uric acid may cause gout attacks or kidney stones. Allopurinol is used to prevent gout attacks, not to treat them once they occur.

How should this medicine be used?

Allopurinol comes as a tablet to take by mouth. It is usually taken once or twice a day, preferably after a meal. To help you remember to take allopurinol, take it around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take allopurinol exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on a low dose of allopurinol and gradually increase your dose, not more than once a week.

It may take several months or longer before you feel the full benefit of allopurinol. Allopurinol may increase the number of gout attacks during the first few months that you take it, although it will eventually prevent attacks. Your doctor may prescribe another medication such as colchicine to prevent gout attacks for the first few months you take allopurinol. Continue to take allopurinol even if you feel well. Do not stop taking allopurinol without talking to your doctor.

What special precautions should I follow?

Before taking allopurinol,

• tell your doctor and pharmacist if you are allergic to allopurinol, any other medications, or any of the ingredients in allopurinol tablets. Ask your pharmacist for a list of the ingredients.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking while you are taking allopurinol. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had high blood pressure, diabetes, kidney or liver disease, or heart failure.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking allopurinol, call your doctor.
• you should know that allopurinol may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
• ask your doctor about the safe use of alcoholic beverages while you are taking allopurinol.

What side effects can this medication cause?

Allopurinol may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea
• diarrhea
• drowsiness

Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, stop taking allopurinol and call your doctor immediately or get emergency treatment:

• rash, itching, or hives
• peeling, blistering, or shedding skin
• red or purple spots on skin
• painful urination
• blood in the urine
• irritation of the eyes
• swelling of the lips or mouth
• fever or flu-like symptoms
• swollen glands
• yellowing of the skin or eyes, pain in the upper right part of the stomach, nausea, vomiting, itching, or extreme tiredness

Allopurinol may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

🔗 Reference: https://medlineplus.gov/druginfo/meds/a682673.html