Allopurinol is a generic prescription drug used to lower uric acid levels in the blood. Uric acid is a normal product of the body’s metabolism, but uric acid can cause problems like gout or kidney stones when levels get too high. When doctors prescribe allopurinol, most people take allopurinol tablets. However, people with high uric acid levels due to cancer chemotherapy may be given intravenous injections.
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Allopurinol overview
BRAND NAMES:
Zyloprim, Aloprim
Generic Names:
Allopurinol
Uses:
Treats gout, kidney stones, and high uric acid levels due to cancer chemotherapy
Therapeutic Classes:
Urinary stone agent, antigout agent, xanthine oxidase inhibitor
Forms:
Tablet, injection
How it’s taken:
By mouth, intravenous injection
What is Allopurinol used for?
Healthcare professionals use allopurinol, a drug that reduces uric acid levels, to treat gout, calcium kidney stones, or high uric acid levels due to cancer chemotherapy, a condition called tumor lysis syndrome. Healthcare professionals may sometimes use it off-label for other conditions caused by high uric acid levels. However, they usually avoid allopurinol treatment when high uric acid levels aren’t associated with symptoms or other problems.
What form(s) does Allopurinol come in
Tablet
100 mg
200 mg
300 mg
Injection
20 mg/mL (after dilution)
What are common Allopurinol doses?
For gout: 200–600 mg tablets taken once per day or in divided doses
For recurrent calcium oxalate stones in people with high uric acid levels: 200–300 mg tablets taken once per day
For tumor lysis syndrome (starting one to two days before chemotherapy treatment and ending two to three days after chemotherapy):
Intravenous dosage: 200–400 mg/day administered in two to four divided doses
Tablet: 300–800 mg/day taken once daily or in divided doses
Individual doses cannot exceed 300 mg. Daily doses that are larger than 300 mg must be taken in divided doses
Find more detailed information about allopurinol dosage, forms, and strengths here.
Common Allopurinol prescriptions
Allopurinol
100mg tabletAllopurinol
200mg tabletAllopurinol
300mg tablet
How to take Allopurinol
Take this medicine as prescribed. Doses will change at the start of treatment.
Do not stop taking allopurinol doses until talking to the prescriber or other healthcare professional. Keep taking doses during gout attacks or if symptoms go away.
Take the tablets at about the same time every day.
Take allopurinol tablets after a meal to avoid stomach upset, nausea, and similar problems.
Swallow allopurinol tablets whole with a glass of water.
Drink at least two liters of fluids daily when taking allopurinol.
Store allopurinol tablets at room temperature in a light-resistant container. Protect from moisture.
What to do if you miss a dose of Allopurinol
If it is almost time for your next dose, wait until then and take a regular dose.
Do not take a double dose to make up for a missed dose.
If a dose is missed and not taken, record the missed dose and tell the prescriber.
Allopurinol contraindications
This medicine is not right for everyone.
Do not use it if you have had an allergic reaction to allopurinol.
Allopurinol warnings
The prescriber will require blood tests before prescribing allopurinol. After you start taking the drug, the prescriber will need regular blood tests and office visits to monitor treatment and monitor for adverse effects. Keep all appointments.
When starting allopurinol, make sure the prescriber knows if you are pregnant, breastfeeding, or have:
Kidney problems
Liver problems
Diabetes
High blood pressure
Allopurinol can cause serious and potentially fatal skin reactions. The risk of a serious drug reaction is higher in people with a gene type called HLA-B*5801. If you know that you have this gene type, tell the prescriber.
Stop taking allopurinol doses and immediately inform the prescriber at the first sign of a skin rash or allergic reaction.
This medicine may cause the following:
Liver problems
Kidney problems
Serious and potentially life-threatening skin reactions
Women should not breastfeed while taking allopurinol or for one week after the last dose has been taken.
When starting allopurinol, you may have more gout flares but do not stop taking doses. During this initial stage of treatment, the prescriber can prescribe medications to treat or prevent gout flares. The attacks should become shorter and less severe after a few months.
Allopurinol interactions
To avoid possible drug interactions, tell the prescriber about all prescription drugs, over-the-counter medications, and supplements being taken, particularly:
Drugs that make you urinate are called thiazide diuretics
The immune suppressants cyclosporine, azathioprine, and mercaptopurine
The gout drug Krystexxa (pegloticase)
The blood thinners warfarin and dicumarol
The antibiotics amoxicillin or ampicillin
Chemotherapy drugs, particularly capecitabine
Find more information about allopurinol interactions to avoid here.
Allopurinol side effects
Serious Side Effects
Allopurinol side effects are relatively minimal and not commonly experienced. Serious side effects are possible but rare. Talk to a doctor if you notice any signs or symptoms of a possible serious side effect, including:
Trouble breathing or slow breathing
Change in how much or how often you urinate, pain when you urinate, cloudy or bloody urine, pain in the flanks of the abdomen
Dark urine or pale stools, loss of appetite, stomach pain, nausea, vomiting, yellow skin or eyes
Fever, fatigue, heart rate abnormalities, skin color changes, and other signs of infection
Blistering, peeling, red skin rash
Allergic reaction: Itchy skin, hives, swelling in your face, mouth, lips, or throat, chest tightness, trouble breathing
Less serious side effects
Allopurinol’s most common side effects have an incidence rate of 1% or less. The most common include:
Nausea
Vomiting
Diarrhea
Find more information about allopurinol side effects here.
Sources:
Allopurinol, Memorial Sloan Kettering Cancer Center
Allopurinol, StatPearls
Aloprim allopurinol injection prescribing information, DailyMed (NIH National Library of Medicine)
The role of allopurinol for gout treatment, Gout Education Society
Zyloprim allopurinol tablet prescribing information, DailyMed (NIH National Library of Medicine)
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