Allopurinol
Generic Zyloprim
Allopurinol (al oh PURE i nole) is a generic medication prescribed for certain conditions related to high uric acid levels. Allopurinol belongs to a group of drugs called xanthine oxidase inhibitors.
Allopurinol (al oh PURE i nole) is a generic medication prescribed for certain conditions related to high uric acid levels. Allopurinol belongs to a group of drugs called xanthine oxidase inhibitors.
- Generic
- • Tablet
- • 300mg
- • 30 Tablets
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Introduction
Written by Sarah Lewis, PharmD
Medically reviewed by Melissa Badowski PharmD, MPH, FCCP
Updated on June 23, 2023
The Food and Drug Administration (FDA) has approved allopurinol to treat:
- gout
- high uric acid levels due to cancer treatment
- certain kinds of kidney stones that keep coming back
These approved uses differ based on the form of allopurinol your doctor prescribes.
This article describes allopurinol’s uses, side effects, and more. You’ll also find some coupon options to help save on the cost of allopurinol.
Uses of allopurinol
The Food and Drug Administration (FDA) approves prescription drugs such as allopurinol for certain conditions. Approved uses for allopurinol are described below. These uses differ based on the form of allopurinol prescribed.
Use for gout
Doctors may prescribe allopurinol oral tablet for treating gout (sometimes called gouty arthritis). It’s used for this purpose in adults. It’s usually prescribed as a long-term treatment.
In people with gout, urate crystals form and deposit in joints. These crystals develop when there are high uric acid levels in the blood. The crystals cause pain and inflammation (swelling and damage).
People who have gout experience sudden flare-ups of pain and inflammation called gout attacks. Allopurinol helps prevent these attacks by lowering uric acid levels. If you have frequent or severe gout attacks, your doctor may prescribe allopurinol.
Use for certain types of kidney stones
Doctors may prescribe allopurinol oral tablet for treating certain types of kidney stones. It’s used for this purpose in adults. It’s usually prescribed as a long-term treatment.
Kidney stones can form from different minerals. Allopurinol is approved to treat the kind called calcium oxalate stones. It’s approved for this use in people with high uric acid levels who keep getting calcium oxalate stones.
Use for certain cancers
Doctors may prescribe allopurinol oral tablet or injection given by intravenous (IV) infusion* for treating high uric acid levels due to cancer treatment. It’s used for this purpose in adults and children. It’s usually prescribed for short-term use during cancer treatment.
With cancer treatment, many cancer cells die very quickly and at the same time. As they die, they release certain chemicals into the blood, including uric acid. Because so many cancer cells die at once, the body can’t get rid of these chemicals fast enough. This condition is called tumor lysis syndrome, and it can result in life threatening complications, such as organ failure.
Tumor lysis syndrome more often occurs from treatment for certain cancers, such as leukemia, lymphoma, and some solid tumor cancers.
* An IV infusion is an injection given into your vein over time.
Common questions about allopurinol
Below you’ll find answers to a few commonly asked questions about allopurinol.
What should I do if I have a gout attack while taking allopurinol?
Keep taking allopurinol if you have a gout attack during treatment with this drug. If your doctor has prescribed drugs to treat gout attacks, start them as instructed. If not, speak with your doctor and let them know you’re having a gout attack. They can recommend a treatment that’s best for you.
To learn more about managing gout attacks, talk with your doctor or pharmacist.
Is allopurinol available over the counter?
No, allopurinol isn’t available over the counter. It’s only available by prescription from your doctor.
If you’re interested in allopurinol as a possible treatment option, talk with your doctor or pharmacist.
Are there brand-name versions of allopurinol?
Yes, there are. Allopurinol oral tablet is available as the brand-name drug Zyloprim. Allopurinol injection given by intravenous (IV) infusion is available as the brand-name drug Aloprim. (An IV infusion is an injection given into your vein over time.)
If you’d like to know more about Zyloprim or Aloprim, talk with your doctor or pharmacist.
How does allopurinol work? And how long does it take to start working?
Allopurinol works by blocking an enzyme called xanthine oxidase. (Enzymes are proteins that aid chemical changes in your body.) Xanthine oxidase breaks down substances in your body known as purines, producing uric acid as a result. By blocking this enzyme, allopurinol stops your body from making uric acid.
Allopurinol starts working right away. But it can take several weeks or a few months to see its full effect. During this time, gout attacks may continue or even increase. This happens because the body has stores of uric acid that are pulled into the blood. It can take time for these stores to get used up.
If you’d like to know more about how allopurinol works, talk with your doctor or pharmacist.
Side effects of allopurinol
Allopurinol may cause mild or serious side effects. More common mild side effects of allopurinol and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.
To learn more about allopurinol’s side effects, see this article or ask your doctor or pharmacist. You can also refer to the prescribing information for allopurinol that’s listed in the “Article resources” section.
Mild side effects
More common mild side effects reported with some forms of allopurinol are listed below. These side effects may differ based on the form of allopurinol you take.
This article doesn’t include all possible mild side effects of the drug. To learn more about allopurinol’s side effects based on the form, see the prescribing information for allopurinol listed in the “Article resources” section.
With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.
Mild side effects of allopurinol oral tablet and injection given by intravenous (IV) infusion* include:
- diarrhea
- drowsiness
- headache
- nausea or vomiting
- mild allergic reaction†
* An IV infusion is an injection given into your vein over time.
† For details about this side effect, see the “Interactions and warnings for allopurinol” section.
Serious side effects
Serious side effects of allopurinol are listed below. These side effects may differ based on the form of allopurinol you take.
This article doesn’t include all possible serious side effects of the drug. To learn more about allopurinol’s side effects based on the form, see the prescribing information for allopurinol listed in the “Article resources” section.
With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.
In general, allopurinol’s serious side effects include:
- blood vessel problems, such as peripheral vascular disease or thrombophlebitis
- heart problems, such as heart failure or blood clots in the lungs
- kidney problems, such as kidney failure
- liver problems, such as liver damage
- low level of red blood cells, white blood cells, or platelets (blood cells that help with clotting)
- muscle weakness
- nerve inflammation or damage
- stroke
- severe allergic reaction*
* For details about this side effect, see the “Interactions and warnings for allopurinol” section.
Interactions and warnings for allopurinol
Below, you’ll find information about allopurinol’s possible interactions and warnings.
Interactions of allopurinol
Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.
Before you take allopurinol, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:
- prescription or over-the-counter drugs
- vitamins, herbs, or supplements
To learn about drug-condition interactions, see the “Warnings for allopurinol” section just below.
Warnings for allopurinol
Some people should not take allopurinol, and others should take it cautiously.
Allopurinol could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether allopurinol is a safe option for you. These warnings may differ based on the form of allopurinol you take.
Ask your doctor about specific warnings for allopurinol, and be sure to tell your doctor about your:
- current health, including any allergies to medications
- past health conditions or surgeries
Allergic reaction
Allopurinol can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.
If you’ve had an allergic reaction to allopurinol or any of its ingredients, your doctor will likely not prescribe allopurinol. They can tell you about medications that are safer options for you.
A mild allergic reaction may cause the following symptoms:
A severe allergic reaction may cause the following symptoms:
- severe skin rashes that may blister and peel
- swelling under your skin, usually in your hands, feet, eyelids, or lips
- swelling of your mouth, throat, or tongue, which can cause breathing problems
If you have an allergic reaction to allopurinol, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.
Overdose of allopurinol
If you take allopurinol by mouth, you should not take more allopurinol than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.
If you think you’ve taken too much allopurinol, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.
Pregnancy or breastfeeding and allopurinol
Information about allopurinol and pregnancy and breastfeeding is described below.
Allopurinol and pregnancy
It’s not known whether allopurinol should be taken during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication.
Allopurinol and breastfeeding
It’s not known whether allopurinol should be taken while breastfeeding.
If you’re receiving allopurinol by intravenous (IV) infusion, you should wait at least 1 week after the last dose before breastfeeding your child.
If you’re breastfeeding or planning to do so, talk with your doctor before taking this medication.
What to ask your doctor
This article describes allopurinol’s uses and side effects, ways to save on cost, and more. Let your doctor know if you have questions about allopurinol or would like more details about it.
Here’s a list of some possible questions you may want to ask your doctor:
- How much fluid do I need to drink each day while taking allopurinol?
- What should I do if I miss a dose of allopurinol?
- Do any of my other medications interact with allopurinol?
- How does allopurinol compare with other drugs that could treat my condition?
Article resources
- Allopurinol for injection, for intravenous use. (2022). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/2caf5eed-2408-4ce0-bd0d-04f4c90e434d/spl-doc
- Allopurinol tablets USP. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/faf55184-6962-d49f-e053-6394a90a152e/spl-doc
- Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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