Allopurinol is used to treat gout and certain types of kidney stones. It is also used to prevent increased uric acid levels in patients receiving cancer chemotherapy. These patients can have increased uric acid levels due to release of uric acid from the dying cancer cells. Allopurinol works by reducing the amount of uric acid made by the body. Increased uric acid levels can cause gout and kidney problems.
Take this medication by mouth, usually once daily or as directed by your doctor. Take this medication after a meal to reduce stomach upset. If your dose is more than 300 milligrams a day, you will need to take several smaller doses during the day to get this amount (ask your doctor for directions).
It is best to drink a full glass of water with each dose and at least 8 more glasses (8 ounces each) of fluid a day. If your doctor has directed you to drink less fluid for other medical reasons, consult your doctor for further instructions. Your doctor may also instruct you on how to decrease acid in your urine (e.g., avoiding large amounts of ascorbic acid/vitamin C).
Dosage is based on your medical condition and response to treatment. Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.
For the treatment of gout, it may take up to several weeks for this medicine to have an effect. You may have more gout attacks for several months after starting this medicine while the body removes extra uric acid. Allopurinol is not a pain reliever. To relieve pain from gout, continue to take your prescribed medicines for gout attacks (e.g., colchicine, ibuprofen, indomethacin) as directed by your doctor.
Tell your doctor if your condition persists or worsens.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if any of these rare but very serious side effects occur: numbness/tingling of arms/legs, easy bleeding/bruising, signs of infection (e.g., fever, persistent sore throat), unusual tiredness, painful/bloody urination, change in the amount of urine, yellowing eyes/skin, severe stomach/abdominal pain, persistent nausea/vomiting, dark urine, unusual weight loss, eye pain, vision changes.
A very serious (possibly fatal) allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking allopurinol, tell your doctor or pharmacist if you are allergic to it; or if you have had a severe reaction to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, kidney disease, diabetes, high blood pressure (hypertension), unusual diets (e.g., fasting).
This drug may make you drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely.
Alcohol may decrease the effectiveness of this drug. Limit alcoholic beverages.
Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, older adults may be at greater risk for side effects while using this drug.
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.
This drug should not be used with the following medication because very serious interactions may occur: didanosine.
If you are currently using this medication, tell your doctor or pharmacist before starting allopurinol.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: certain asthma drugs (aminophylline, theophylline), azathioprine, "blood thinners" (e.g., warfarin), chlorpropamide, cyclosporine, mercaptopurine, "water pills" (e.g., thiazide diuretics such as hydrochlorothiazide).
This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
If overdose is suspected, contact a poison control center or emergency room right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
Do not share this medication with others.
Laboratory and/or medical tests (e.g., uric acid blood levels, liver/kidney function tests, complete blood count) may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
If you are taking allopurinol to treat kidney stones, you may benefit from a special diet. Consult your doctor for more details.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Store the US product at room temperature between 59-77 degrees F (15-25 degrees C) away from light and moisture. Do not store in the bathroom.
Store the Canadian product at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture.
Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised March 2013. Copyright(c) 2013 First Databank, Inc.
With WebMD's Medicine Cabinet, you can check interactions with drugs.Go to medicine cabinet