Allopurinol

WHY is this medicine prescribed?

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.

Are there OTHER USES for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

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 SPECIAL DIETARY instructions should I follow?

Drink at least eight 8-ounce (240-milliter) cups of water or other liquids each day while taking allopurinol unless directed to do otherwise by your doctor.

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine 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).

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (https://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location — one that is up and away and out of their sight and reach. https://www.upandaway.org

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to allopurinol.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking allopurinol.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™. © Copyright, 2024. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: September 15, 2023.