The Role of Allopurinol in Treating Gout

Taking uric acid-lowering medications, like allopurinol, can help to avoid serious symptoms of gout, like gout attacks. This is because lower uric acid levels reduce the chances of uric acid crystals forming.

While taking steps, such as following a healthy, balanced diet, staying hydrated, and getting regular exercise, research has shown that these lifestyle changes can only lower serum uric acid by so much. Making healthy dietary changes or weight loss has been shown to lower uric acid levels by only 1.0 to 2.0 mg/dL, which is insufficient to reach a health target for gout sufferers.

While healthy lifestyle changes are important for anyone who has or who is at risk for gout, taking daily medications—like allopurinol—as prescribed by a doctor, is one of the best ways to reduce levels of uric acid to less than 6.0 mg/dL or lower, depending on the doctor’s recommendations.

The accumulation of uric acid and the formation of crystals is what ultimately leads to the pain and tissue destruction of gout. Increased uric acid levels, if not treated properly over time with medications like allopurinol, more gout attacks can occur.

When prescribing medication for gout, the healthcare professional—whether a primary care physician, nephrologist, or rheumatologist who specializes in gout care—will take a person’s current serum uric acid (sUA) levels, additional health conditions, and other factors (e.g., dietary and lifestyle choices) into consideration when deciding on the best treatment for a gout management plan.

Gout is diagnosed clinically by characteristic gout flares along with blood tests, and occasionally, extraction of synovial fluid from an affected joint. Once diagnosed, you will likely be given a daily medication, like allopurinol, as part of your treatment plan. Allopurinol is a first-line treatment for reducing sUA levels, which will lead to decreased numbers of painful attacks in the future.

Once a medication like allopurinol to treat gout is started, it should be continued unless you experience an adverse reaction to the medicine. Even if your inflamed joints return to normal, the underlying cause of the disease—elevated sUA—needs to be controlled and gout management is a life-long process.

Read on to learn more about allopurinol, specifically for the treatment of gout; how to use it; side effects; drug interactions; and more. Always call your doctor for personalized medical advice and never abruptly stop taking allopurinol, or other medications, without first consulting your doctor.

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What is allopurinol?

Allopurinol is a medication used to fight increased uric acid levels in those who have gout.

The drug allopurinol works as an oral tablet prescription medication and is the most often prescribed for the treatment of gout. Allopurinol can also be prescribed to prevent kidney stones or recurrent kidney stones, and can be used in patients receiving cancer treatment.


What are other names for allopurinol?

Allopurinol is known by the brand names Lopurin®, Zyloprim® and Aloprim®. However, generic drugs—or other forms of allopurinol—have been shown to be just as effective as brand-name options.

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How is allopurinol taken?

Allopurinol is only available as an oral tablet for the treatment of gout or kidney stones.

What is the typical dosage of allopurinol?

The correct dose of allopurinol is one that causes sUA level to drop below 6.0 mg/dL. This dose varies from patient to patient. The minimum or maximum dose for each person is not predictable by the patient’s size, gender or age. The American College of Rheumatology recommends that all people with gout start allopurinol at a low dose and gradually build the dose until the levels in the blood reaches the target. For most people, the starting dose of allopurinol tablets is 100 mg daily. For those with significant kidney health issues, the initial dose should be lower. The average dose of allopurinol needed to get an sUA level to target in patients with gout is about 400 mg per day. The approved range for allopurinol is between 100 mg and 800 mg per day maximum dose.

Proper use of allopurinol

Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand and to provide medical advice.

Do not stop taking allopurinol without talking to your doctor.

As with other drugs, keep allopurinol in the container it came in so you have access to the drug information.

Be sure to store allopurinol tightly closed at room temperature away from moisture and out of reach of children. Keep track of any missing or divided doses.

If pets, children or anyone else takes your allopurinol, call your local poison control center. To dispose of any prescribed medicines, consult your local waste disposal company.

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How and when to take allopurinol

Take your allopurinol around the same time every day, as directed by your doctor.

Since allopurinol may not stop gout attacks at first, continue to take the medicine even if you experience a flare.

It may be many months to a couple of years before all of your gout symptoms disappear after starting allopurinol.

Your doctor may start you on a low dose (100 mg daily) and gradually increase it over time in order to lower your uric acid levels and prevent a future gout attack.

What happens if you miss a dose?

The tablet should be taken around the same time every day, as directed by your doctor. If the time you usually take allopurinol passes and you miss a dose, take your usual 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.

Be sure to tell your doctor if you skip the missed dose, and how often you have a missed dose.

Do not take a double dose to make up for a missed one. Take your next dose as usual.

How long does it take allopurinol to work?

As a medication, allopurinol belongs to a class of drugs known as xanthine oxidase inhibitors. These medications block the enzyme that makes uric acid, stopping more from being produced and allowing the body to decrease acid and process the high level that is already in the bloodstream and accumulated in and around the joints.

Uric acid levels in the blood will begin to drop within one to two weeks of starting allopurinol. However, it may take months to years for the crystals in and around the joints to dissolve and be eliminated.

You should never stop or start treatment of allopurinol without consulting your doctor.

Should allopurinol be taken in combination with other medications?

Your doctor may instruct you to take allopurinol in combination with other medications for the treatment of gout or other conditions, such as diabetes, kidney health issues (to prevent kidney stones), or heart health issues.

Allopurinol is not meant to treat pain from gout flares, but your doctor may combine allopurinol with other medications that do treat pain, such as colchicine, non-steroidal anti-inflammatory drugs (NSAIDS) like ibuprofen or naproxone, and in some cases, steroids such as prednisone.

If you are prescribed allopurinol or other medications, it is important that you follow all directions on your medical labels and all drug-specific instructions. Ask your healthcare professional if you don’t understand the directions for allopurinol.

It is also important to talk to your doctor if your symptoms worsen, or if you do not believe it is effective. Your doctor may alter your treatment plan or recommend higher or divided doses of allopurinol.

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Considerations when taking your allopurinol medication regularly

While drinking water to stay hydrated is already important for your overall health and to reduce uric acid, drinking a full glass of water with each dose of allopurinol is important. Beyond this, it is recommended to drink at least eight or more 8 oz. glasses of water per day. Drinking plenty of water helps flush more uric acid from the kidneys.

If you are taking allopurinol, you should take it at about the same time every day. Be sure to continue to take allopurinol regularly, and as prescribed, to continue to decrease high uric acid levels that can lead to painful gout flares.

Even months after you start taking allopurinol and your uric acid level is at the target of less than 6.0 mg/dL, you may still experience gout flares until the allopurinol has had time to dissolve all the uric acid crystals around the body. This may take one to several years.

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Potential common side effects when taking allopurinol

Allopurinol is generally well tolerated. There are some possible side effects that you should be aware of and tell your doctor if you are taking allopurinol.

However, allopurinol use does not cause unusual tiredness. Most important of these is the development of a rash. If a rash occurs, you should stop the medication immediately and contact your doctor.

Common side effects of allopurinol include:

  • Skin rash
  • Change in taste
  • Diarrhea
  • Nausea, stomach pain, or indigestion
  • Changes in liver function test results
  • Initial gout flares

Taking allopurinol after you eat meals helps reduce the chance of other side effects, such as stomach pain.

While allopurinol is meant to lower uric acid, you may experience more gout attacks and joint pain during the first few months as uric acid levels regulate. Your doctor may prescribe colchicine or other pain management options along with allopurinol to control your gout symptoms and further attacks.

Mild side effects should subside within a few days, or up to a couple of weeks. Developing a new rash, whether a mild or severe reaction, after starting allopurinol should lead to immediate discontinuation of the drug and you should call your doctor immediately.

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Potential rare, but serious side effects when taking allopurinol

Rare, but serious symptoms include:

  • Serious allergic reaction
  • Severe skin rash — itchy hives, red- or purple-colored spots, scaly skin reactions
  • Fever, chills or trouble breathing
  • Swelling of your face or throat
  • Liver injury — tiredness, lack of appetite, weight loss, upper abdominal pain or discomfort, jaundice (dark urine or yellowing of your skin or whites of your eyes)

Talk to your doctor if you experience any serious side effects, such as allergic reactions. If you develop a skin rash, tell your doctor or pharmacist right away, as you may be asked to discontinue using allopurinol.

A serious allergic reaction could mean you have allopurinol hypersensitivity syndrome, which is rare—only 1 in 1,000 patient cases. Patient populations with increased risk — including people who are Han Chinese or Southeast Asian, and Koreans with kidney disease — can be screened for a genetic marker (HLA-B5801) that can predict this allergic reaction as one of the side effects of taking allopurinol.

To determine any allergic reactions, doctors will start you on a low dose with a plan to increase the allopurinol to the optimal medication dose.

If you have kidney or liver disease, your health care professional can help advise on whether medications like allopurinol are your best treatment option.

You should know this

What else to know before taking allopurinol

Since some people may have an allergic reaction to allopurinol, be sure to tell your doctor or pharmacist if you’ve had had any reactions to allopurinol or side effects from using it in the past. Tell your doctor if you have any other allergies to medications.

You should also share with your doctor if you’ve had any medical history of liver disease, kidney disease, diabetes or high blood pressure (hypertension).

Alcohol can limit the effectiveness of allopurinol, so limit drinking alcoholic beverages.

Older adults with limited kidney function may be at greater risk for side effects.

If pregnant or breastfeeding, allopurinol should only be used when very necessary, since it passes into breast milk. Be sure to call your doctor and further consult with your health care providers if you are pregnant or are trying to become pregnant.

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Allopurinol drug interactions

Other drugs can affect allopurinol and interact with it, reducing its effectiveness. They specifically can interact with blood thinners, also known as anticoagulants or anti-platelet drugs, which are prescribed to prevent blood clots or keep existing clots from getting larger, ultimately reducing the risk of stroke or heart attack.

Heparin or warfarin, which is also called by the brand name Coumadin®, are anticoagulants. Aspirin is a type of anti-platelet drug.

Be sure to mention any of the following other drugs to your doctor to prevent other medicines from interacting with the allopurinol:

  • Antibiotics such as amoxicillin (Amoxil, Trimox), ampicillin (Polycillin, Principen)
  • Cancer treatments and other medicines that suppress the immune system such as cyclophosphamide (Cytoxan), mercaptopurine (Purinethol), and azathioprine (Imuran)
  • Chlorpropamide (Diabinese) to treat diabetes
  • Diuretics (known as “water pills”) for high blood pressure

Your doctor may need to change the doses of your other medicines or monitor you carefully for side effects.