Uses
What is allopurinol used for?
Allopurinol is commonly used to treat gout, which is a form of arthritis caused by too much uric acid in your blood and joints.
Allopurinol may also be used to lower your uric acid levels if you are receiving chemotherapy for cancer, or if you have certain types of kidney stones.
Allopurinol may also be used for other conditions as determined by your healthcare provider.
How does allopurinol work (mechanism of action)?
Allopurinol works by reducing the production of uric acid in your body. If uric acid levels get too high, crystals can form in your joints and cause inflammation and pain (gout flares) or stones can form in your kidneys. By reducing the formation of uric acid, allopurinol helps prevent gout flares and kidney stones.
How is allopurinol supplied (dosage forms)?
Allopurinol is available as Lopurin, Zyloprim, and generic allopurinol in the following dosage forms that are taken by mouth.
- 100 mg oral tablets
- 200 mg oral tablets
- 300 mg oral tablets
How should I store allopurinol?
Allopurinol should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C), for shorter periods of time, such as when transporting it. Store in a cool, dry place. Keep tightly closed.
Side Effects
What are the most common side effects of allopurinol?
The most common side effects of allopurinol are listed below. Tell your healthcare provider if you have any of these side effects that bother you.
- Skin rash (see below)
- Diarrhea
- Nausea
There may be other side effects of allopurinol that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of allopurinol?
While less common, the most serious side effects of allopurinol are described below, along with what to do if they happen.
Gout Flares. Allopurinol may increase your gout flares before making your symptoms better. It may take several months to reduce uric acid levels enough to control your gout flares. It is very important to follow your healthcare provider’s recommendations, which may include taking medicine for pain and inflammation while taking allopurinol, and drinking enough fluids.
Kidney Damage. Kidney damage can happen when taking allopurinol. Call your healthcare provider right away if you have any of the following symptoms of kidney damage.
- Reduced need to pee
- Swelling in your feet, ankles, or legs
- Weakness or unusual tiredness
- Difficulty catching your breath or chest pain/pressure
- Confusion
- Nausea
- Seizures
Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking allopurinol. Call your healthcare provider right away if you have any of the following symptoms of liver damage.
- Nausea or vomiting
- Stomach or belly pain
- Fever
- Weakness or unusual tiredness
- Itching
- Loss of appetite
- Light-colored poop
- Dark-colored urine
- Your skin or the whites of your eyes turning yellowish in color (also called jaundice)
Blood Disorders. Allopurinol can cause blood disorders, such as agranulocytosis, aplastic anemia, hemolytic anemia, low platelet levels (thrombocytopenia), and low white blood cell levels (leukopenia). Stop using allopurinol and get help right away if you have any of the following symptoms of blood disorders.
- Fever
- Shortness of breath
- Pale or yellowish skin
- Easy bruising or bleeding
- Frequent infection
- Unusual weakness or tiredness
- Dizziness, lightheadedness, or feeling like you are about to pass out
- Headache
- Fast or abnormal heartbeat
Dizziness and Sleepiness. Allopurinol can make you dizzy or sleepy. Do not drive or do other activities that require alertness or coordination until you know how allopurinol affects you.
Severe Skin Reactions. Allopurinol can cause severe skin reactions called Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) that can lead to death if not treated. If you develop a rash, stop allopurinol and call your healthcare provider right away. Get emergency help right away if you have any of the following symptoms of SJS or TEN.
- Painful red or purple skin that looks burned and peels off
- Flat red rash or blisters on your skin, mouth, nose, and genitals
- Red, painful, watery eyes
Severe Allergic Reactions. Allopurinol may cause allergic reactions, including a specific type of allergic reaction called DRESS. DRESS stands for Drug Reaction with Eosinophilia and Systemic Symptoms. It is also sometimes called multiorgan hypersensitivity. This is a reaction that can affect multiple parts of the body, including your liver, kidneys, and heart. Stop taking allopurinol and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching, skin rash, or pale red bumps on the skin called hives
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
- Dark-colored pee
- Your skin or the whites of your eyes turning yellowish in color (also called jaundice)
Warnings & Precautions
Who should not use allopurinol?
Allergies to Ingredients. People who are allergic to any of the following should not use allopurinol.
- Allopurinol
- Lopurin
- Zyloprim
- Any of the ingredients in the specific product dispensed
Your pharmacist can tell you all of the ingredients in the specific allopurinol products they stock.
What should I know about allopurinol before using it?
Do not take allopurinol unless it has been prescribed to you by a healthcare provider. Take it as prescribed.
Do not share allopurinol with other people, even if they have the same condition as you. It may harm them.
Keep allopurinol out of the reach of children.
If you are being treated for gout, your symptoms may get worse before getting better while taking allopurinol. Talk to your healthcare provider about managing gout flares while taking allopurinol.
Take allopurinol after a meal to limit stomach upset.
Stay well hydrated to prevent kidney stones.
What should I tell my healthcare provider before using allopurinol?
Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if allopurinol is right for you.
Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.
- Kidney problems
- Liver problems
- Blood disorders
- Cancer
African, Asian, Native Hawaiian/Pacific Islander Ancestry. Tell your healthcare provider if you are of African, Asian, Native Hawaiian or Pacific Islander Ancestry. If you are of one of these ancestries, your healthcare provider may wish to perform genetic testing to determine your risk of a specific allergic reaction to allopurinol.
Other Medicines and Supplements. Allopurinol may interact with other medicines and supplements. Before taking allopurinol, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.
Pregnancy. It is not known if or how allopurinol could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take allopurinol while you are pregnant or trying to get pregnant.
Breastfeeding. Do not take allopurinol while you are breastfeeding and for one week after your last dose. Allopurinol passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.
Interactions
Does allopurinol interact with foods or drinks?
There are no known interactions between allopurinol and foods or drinks.
It is unknown if drinking alcohol will affect allopurinol. The risk of dizziness and drowsiness may be increased if you drink alcohol while taking allopurinol.
Does allopurinol interact with other medicines (drug interactions)?
Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
In particular, make sure that you discuss if you are using any of the following before taking allopurinol.
- Any thiazide diuretic, including hydrochlorothiazide and chlorthalidone, which are commonly used to reduce fluid buildup (edema) or lower blood pressure
- Ampicillin or amoxicillin, which are antibiotics used to treat infections
- Cyclosporine (Gengraf, Neoral, Sandimmune, and others), which is a medicine to suppress your immune system
- Any medicine used to treat cancer
- Mercaptopurine or azathioprine, which are used to suppress your immune system in treating certain diseases
- Theophylline, which is used to treat certain breathing conditions
- Pegloticase (Krystexxa) or probenecid, which are other medicines used to treat gout
- Warfarin (Jantoven), which is a blood thinner
This may not be a complete list of medicines that can interact with allopurinol. Always check with your healthcare provider.
Overdose/Missed Dose
What should I do if I accidentally use too much allopurinol?
If you or someone else has used too much allopurinol, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
What should I do if I miss a dose of allopurinol?
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.
Are you currently using Allopurinol?
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