Allopurinol

💊 What is Allopurinol used for?

• •Managing adults with gout, including gout attacks, tophi (lumps of uric acid deposits), joint damage, uric acid kidney stones, and kidney disease caused by gout.
• •Managing adults and children with leukemia, lymphoma, or solid tumor cancers who are receiving cancer therapy that raises uric acid levels in the blood and urine.
• •Managing adults with recurrent calcium oxalate kidney stones when uric acid levels in the urine stay high despite lifestyle changes.
• •The label says allopurinol is not recommended for asymptomatic hyperuricemia (high uric acid levels without symptoms).

How it works

The label describes allopurinol as a xanthine oxidase inhibitor. The uses listed in the label center on lowering or managing uric acid levels in the blood and urine. The label does not give further detail on how this happens.

How it is usually taken

• •The label says to take allopurinol after meals to lower the chance of stomach irritation. Your prescriber sets the dose and may change it over time based on blood tests, including uric acid levels and kidney function. The label describes the dose being raised in small steps until a uric acid target is reached. Follow the instructions from your prescriber or pharmacist. Before treatment starts, the label says your prescriber should check uric acid, blood counts, chemistry panel, and liver and kidney function.

Comes as

• •100 mg tablets: white to off-white, round, flat, beveled, uncoated, scored tablets.
• •300 mg tablets: white to off-white, round, flat, beveled, uncoated, scored tablets.
• •Inactive ingredients include croscarmellose sodium, lactose monohydrate, magnesium stearate, pregelatinized starch, and povidone.

⚠️ Allopurinol side effects

🛑 Who should not take Allopurinol, and who should be careful

The label says not to take it if

• 🚨You have had a hypersensitivity (allergic-type) reaction to allopurinol.
• 🚨You are known to be sensitive to any of the ingredients in allopurinol tablets.

Tell your doctor before taking it if

• •Tell your prescriber about your full medical history, including kidney problems, liver problems, and any past blood problems.
• •Your prescriber should check blood tests before you start, as the label describes.
• •Tell your prescriber about all medicines you take, including over-the-counter products and supplements.
• •The label notes a gene marker called HLA-B*58:01 that is linked to a higher risk of severe skin reactions. It is more common in people of African, Asian, and Native Hawaiian or Pacific Islander ancestry. The label says screening may be considered before starting in populations where this marker is common, and that screening is generally not recommended in populations where it is rare.
• •The label says allopurinol may cause drowsiness, somnolence, and dizziness. Avoid driving or operating dangerous machinery until you know how the medicine affects you.
• •Tell your prescriber if you are pregnant, planning a pregnancy, or breastfeeding.

🔀 Allopurinol with other medicines, food and alcohol

The label says to discuss these with your doctor or pharmacist

• •Bendamustine, thiazide diuretics, ampicillin, and amoxicillin may increase the risk of skin rash, which may be severe. The label says thiazide diuretics combined with kidney impairment may raise this risk further.
• •Capecitabine: the label says to avoid using allopurinol during treatment with capecitabine.
• •Mercaptopurine or azathioprine: the dose of these medicines may need to be reduced, as recommended in their prescribing information.
• •Pegloticase: the label says to stop and not start allopurinol when pegloticase is used.
• •Dicumarol, warfarin, sulfinpyrazone, and theophylline are listed as medicines that may cause adverse effects when used with allopurinol.
• •Chlorpropamide: allopurinol can prolong its effects. The label notes a possible increased risk of low blood sugar in people with kidney insufficiency.
• •Cyclosporine: allopurinol can increase cyclosporine levels. The label advises closer monitoring.
• •Alcohol and other central nervous system depressants: effects such as drowsiness may add up.
• •The label says the full list of significant interactions is in the full prescribing information. Always share your complete medicine list with your prescriber or pharmacist.

Alcohol and food

The label says to take allopurinol after meals. It also says allopurinol can cause drowsiness and dizziness, and that its central nervous system effects may add to those of alcohol. The label advises adults to drink plenty of fluids, at least 2 liters a day, and to stay well hydrated to help prevent kidney stones.

🤰 Allopurinol in pregnancy and breastfeeding

Pregnancy

The label says allopurinol may cause fetal harm based on animal findings. Limited human data are described: among about 50 pregnancies in published literature, 2 infants with major congenital malformations were reported after maternal allopurinol exposure. The label states the background risk of birth defects and miscarriage is present in all pregnancies. The label advises women to notify their healthcare provider if they become pregnant or intend to become pregnant during treatment.

Breastfeeding

The label advises women not to breastfeed during treatment with allopurinol and for one week after the last dose.

🗓️ Storage, missed doses and taking too much

Storage

Store at 20°C to 25°C (68°F to 77°F) in a dry place. Keep in a tight container, as defined by the USP.

If a dose is missed

The label says that if a single dose is occasionally forgotten, there is no need to double the dose at the next scheduled time.

If too much is taken

The label states there is no specific antidote for allopurinol overdose. Both allopurinol and oxypurinol can be removed by dialysis, but the label says the usefulness of hemodialysis or peritoneal dialysis for allopurinol overdose is unknown. If you think someone has taken too much, follow the guidance of your prescriber, pharmacist, or emergency services right away.

🗒️ Questions to ask about Allopurinol

• What dose of allopurinol is right for my condition, and how often will my uric acid level be checked?
• Will I need to take a preventive medicine, such as colchicine, along with allopurinol to avoid gout flares?
• What blood tests do I need before starting, and how often will I need them afterward?
• Am I at higher risk for a serious skin reaction based on my ancestry or my genetic test results?
• What should I do if I get a skin rash, and whom should I call?
• Could allopurinol interact with my other medicines, including any over-the-counter products or supplements?
• How should I plan for pregnancy or breastfeeding while taking allopurinol?

❓ Allopurinol: frequently asked questions