Side effects of allopurinol – NHS

Like all medicines, allopurinol can cause side effects, but many people have no side effects or only minor ones.

Common side effects

There are things you can do to cope with these common side effects of allopurinol:

Feeling or being sick (nausea or vomiting)

If you’re feeling sick, eat little and often and drink lots of fluids such as water or squash. Also try taking your medicine with, or just after, a meal or snack. Stick to simple meals and do not eat rich or spicy food.

If you’re being sick, take small, frequent sips of water to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.

If you take contraceptive pills and you’re being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Serious side effects

It’s unusual to have serious side effects after taking allopurinol. Tell a doctor or contact 111 straight away if:

• the whites of your eyes or your skin turn yellow, although this is less obvious on black or brown skin – these can be signs of a liver problem
• you get a high temperature, sore throat and swollen glands or feel generally unwell – this could mean there are problems with your white blood cells
• you have bruising for no obvious reason or bleeding gums (which takes a long time to stop) when brushing your teeth
• you are unusually thirsty, going to the toilet to pee a lot, unusually tired, losing weight without trying, or have blurred vision – these could be signs of diabetes

Skin rashes

Stevens-Johnson syndrome is a rare side effect of allopurinol. It causes flu-like symptoms, followed by a red or purple rash that spreads and forms blisters. The affected skin eventually dies and peels off.

It’s more likely to happen in the first 8 weeks of taking allopurinol, or when the dose is increased too quickly. It can also happen if allopurinol is stopped suddenly for a few days and then restarted at the same dose as before. It’s better to reduce the dose and then increase it slowly.

Stevens-Johnson syndrome is more common in:

• children
• people who developed a rash with an epilepsy medicine in the past
• people who are allergic to an antibiotic called trimethoprim
• people also taking a medicine called sodium valproate

To help prevent the chance of you getting a rash that could be confused with Stevens-Johnson syndrome, it’s best not to try new medicines or food during the first 3 months of treatment with allopurinol.

It’s also best to not start taking allopurinol within 2 weeks of a viral infection, vaccination, or rash caused by something else.

Immediate action required: Go to A&E now if:

• you get a skin rash with flushing, blisters or ulcers – these can be signs of Stevens-Johnson syndrome

Find your nearest A&E

Serious allergic reaction

In rare cases, it’s possible to have a serious allergic reaction (anaphylaxis) to allopurinol.

Immediate action required: Call 999 or go to A&E now if:

• you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
• you’re wheezing
• you get tightness in the chest or throat
• you have trouble breathing or talking
• your mouth, face, lips, tongue or throat start swelling

You could be having a serious allergic reaction and may need immediate treatment in hospital.

Other side effects

These are not all the side effects of allopurinol. For a full list, see the leaflet inside your medicines packet.

Information:

You can report any suspected side effect using the Yellow Card safety scheme.

Visit Yellow Card for further information.

Page last reviewed: 23 January 2023

Next review due: 23 January 2026

Allopurinol – StatPearls – NCBI Bookshelf

Continuing Education Activity

Allopurinol, a xanthine oxidase inhibitor, is a urate-lowering medication that is FDA approved for managing gout, preventing tumor lysis syndrome, and preventing recurrent calcium nephrolithiasis in patients with hyperuricosuria. Other non-FDA-approved indications include Lesch-Nyhan syndrome-associated hyperuricemia and the prevention of recurrent uric acid nephrolithiasis. It is important to note that asymptomatic hyperuricemia is not an indication of allopurinol or any urate-lowering therapy. This activity outlines the indications, mechanism, pharmacology, contraindications, and adverse events associated with allopurinol drug therapy.

Objectives:

• Identify the various indications, both approved and off-label, for allopurinol therapy.

• Describe the potential adverse effects of allopurinol.

• Summarize the mechanism of action of allopurinol.

• Review the importance of coordinating and collaborating among various disciplines in an interprofessional health team to coordinate care and management to enhance outcomes for patients receiving allopurinol therapy.

Access free multiple choice questions on this topic.

Indications

Allopurinol, a xanthine oxidase inhibitor, is a urate-lowering medication.

Allopurinol is FDA approved for the following indications:

1. Gout

2. Prevention of tumor lysis syndrome

3. Prevention of recurrent calcium nephrolithiasis in patients with hyperuricosuria 

Other non-FDA-approved indications include Lesch-Nyhan syndrome-associated hyperuricemia and recurrent uric acid nephrolithiasis prevention. [1]

American College of Rheumatology recommends initiating urate-lowering therapy such as allopurinol in patients with an established diagnosis of gouty arthritis in the following situations:

1. Frequent attacks of acute gouty arthritis, defined as equal to or more than two attacks per year

2. Chronic kidney disease stage 2 or worse

3. Presence of tophi or tophus on clinical exam or imaging

4. History of nephrolithiasis

It is important to note that asymptomatic hyperuricemia is not an indication of allopurinol or any urate-lowering therapy.[1]

Van Liere E. et al. conducted a study on using low-dose azathioprine and allopurinol (LDAA) to treat inflammatory bowel disease. Allopurinol was added to azathioprine to improve its tolerability. The investigators found that LDAA was better tolerated in patients compared with standard azathioprine monotherapy.[2]

Mechanism of Action

Allopurinol undergoes metabolism in the liver, where it transforms into its pharmacologically active metabolite, oxypurinol. The half-life of allopurinol is 1 to 2 hours, and oxypurinol is about 15 hours. Both allopurinol and oxypurinol are renally excreted. Allopurinol and oxypurinol both inhibit xanthine oxidase, an enzyme in the purine catabolism pathway that converts hypoxanthine to xanthine to uric acid.

Schmidt A. et al. conducted a clinical trial on the analgesic effects of allopurinol in patients undergoing hysterectomy. The investigators found that allopurinol given as a pre-anesthetic agent reduced pain scores 2 hours after surgery.[3]

Fagundes A. et al. conducted a study (12 women) on allopurinol treatment in patients with fibromyalgia.[4] Allopurinol treatment reduced pain. However, in a larger study (N = 31 for allopurinol and N = 29 for placebo), allopurinol did not demonstrate analgesic properties in fibromyalgia patients.[5]

Hsu F. et al. found evidence that medium to high doses of allopurinol reduced colorectal cancer risk in patients.[6]

Park S. et al. found that allopurinol was renoprotective in patients with hyperuricemia and chronic kidney disease compared to febuxostat treatment. [7]

Prieto-Moure B. et al. conducted research on small intestine ischemia-reperfusion injury of Wistar rats and the role of allopurinol and dantrolene in preventing oxygen-free radical damage. The researchers found that the allopurinol and dantrolene combination provided antioxidant effects, which decreased the oxygen-free radical damage caused by the ischemia-reperfusion in the rat’s small intestines.[8]

Administration

Allopurinol administration can be in two forms: oral or intravenous (IV). While oral administration is the standard route for gout and uric acid or calcium oxalate nephrolithiasis, IV allopurinol is for the prevention of tumor lysis syndrome and management of cancer therapy-induced hyperuricemia in patients who cannot tolerate oral therapy.

For long-term gout treatment, the recommended starting dose of allopurinol is 100 mg daily, to be escalated by 100 mg every 2 to 5 weeks until the target serum uric acid is achieved. American College of Rheumatology recommends target uric acid of less than 6. 0 mg/dL for all patients with gout and less than 5.0 mg/dL in patients with tophaceous gout. The maximum daily allopurinol dose is 800 mg. Following the patient reaching the target serum uric acid concentration, the required dose of allopurinol to achieve the target serum uric acid concentration should continue indefinitely.[1]

In patients with renal insufficiency (chronic kidney disease stage 4 and greater), allopurinol should start at a 50 mg daily dose, and the dose shall be escalated by 50 mg every 2 to 5 weeks until reaching the target serum uric acid.[9] Allopurinol and oxypurinol are both dialyzable. In patients with end-stage renal disease on hemodialysis or peritoneal dialysis, allopurinol can be initiated at 50 mg on alternate days and be given post dialysis, with cautious dose escalation to achieve target serum uric acid.

To prevent tumor lysis syndrome, allopurinol shall be initiated 2 to 3 days before starting chemotherapy and continued until 3 to 7 days after chemotherapy. 2/day in three divided doses every 8 hours, a maximum of 800 mg daily, and IV allopurinol is 200 to 400 mg/m2 daily single doses or 2 to 3 divided doses.

Allopurinol dosing is 300 mg oral daily for the prevention of recurrent uric acid or calcium nephrolithiasis.

Adverse Effects

Allopurinol is a relatively safe medication, although adverse effects can occur.

Due to the destabilization of intra-articular uric acid microtophi on initiating any urate-lowering therapy, there is an increased incidence of acute gouty flares, especially during the initial few months. To prevent this, patients should start an anti-inflammatory agent such as colchicine, nonsteroidal anti-inflammatory drug (NSAID), or low-dose prednisone (only in patients who cannot take colchicine or NSAIDs) before or at the same time as initiating allopurinol.[10]

Maculopapular pruritic rash, and gastrointestinal adverse effects, including nausea and diarrhea, are other common adverse effects. Laboratory abnormalities can occur, including transaminitis and elevated serum alkaline phosphatase, leukopenia, and thrombocytopenia. Other less common and rare adverse effects include liver necrosis, granulomatous hepatitis, cholestatic jaundice, interstitial nephritis, and vasculitis.

Fontana R. et al. conducted research on eleven patients with suspected allopurinol-induced liver damage. The researchers found that hepatoxicity was associated with the following alleles: HLA-B*58:01, HLA-B*53:01, and HLA-A*34:02. The median age was 60 years, 54% were men, and 63% were African-American.[11]

Allopurinol maintenance therapy may increase thyroid-stimulating hormone, which might result from subclinical hypothyroidism.[12]

Allopurinol hypersensitivity syndrome (AHS) is a rare severe adverse effect of allopurinol with an incidence of about 1 in 1000, with a high mortality rate of 20% to 25%. The mechanism is a T-cell-mediated immune reaction to oxypurinol. The highest risk is in the first few months of therapy, especially with higher starting doses of allopurinol. Concurrent diuretics, especially thiazide use, renal insufficiency stage 3, or higher, are major risk factors. Patients of Korean, Han Chinese, and Thai descent with HLA-B*5801 genotype are at a very high risk of AHS. Clinical features of AHS include Stevens-Johnson syndrome, toxic epidermal necrolysis, vasculitis, hepatocellular injury, acute kidney injury, fever, leukocytosis, and eosinophilia.[13] Management is supportive. Lowering the starting dose of allopurinol to less than 100 mg daily in all patients and less than 50  mg daily in patients with chronic kidney disease stage 3 or worse can lower the risk of AHS. Wong C et al. conducted pharmacogenomic testing (HLA-B*58:01 allele) on patients with chronic kidney disease before initiating allopurinol treatment.[14] The pharmacogenomic screening prevents allergic skin reactions, and it is cost-effective.

Lavu A. et al. reported on a patient with Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) caused by allopurinol. The patient’s clinical presentation gradually resolved with the discontinuation of allopurinol therapy. The patient was found to have the HLA-B*58:01 allele. The investigators recommend pharmacogenomic testing for the HLA-B*58:01 allele before initiating allopurinol therapy to prevent SJS and TEN in susceptible patients.[15]

Several drug interactions exist with allopurinol. The most important drug interaction is with azathioprine and 6-mercaptopurine, both metabolized by the enzyme xanthine oxidase. Using any xanthine oxidase inhibitor such as allopurinol in a patient on azathioprine or 6-mercaptopurine can cause severe agranulocytosis and pancytopenia.

Contraindications

The presence of the HLA-B*5801 genotype in patients of Korean descent with chronic kidney disease stage 3 or worse, or in patients of Han Chinese or Thai descent irrespective of renal function, is an especially high risk of AHS (hazard ratio of several hundred). American College of Rheumatology recommends screening this population for HLA-B*5801 genotype using the polymerase chain reaction (PCR) testing before initiating allopurinol and, if positive, using an alternative urate-lowering therapy. However, universal HLA-B*5801 allopurinol screening is not recommended, given the significantly lower HLA-B*5801 prevalence and hazard ratio in other populations.

Monitoring

Complete blood count, liver function tests, renal function, and serum uric acid levels shall be measured every 2 to 5 weeks while titrating the dose until achieving the target serum uric acid level and every six months thereafter. Patients need counseling about the signs and symptoms of AHS with a recommendation to discontinue allopurinol promptly if they develop skin rash concerning AHS, especially early in therapy. 

The manufacturer recommends that patients on allopurinol discontinue the drug for one week before breastfeeding. However, the mother could continue allopurinol therapy in exclusively breastfed babies with careful monitoring of the child for allergic reactions and complete blood counts.[16]

Enhancing Healthcare Team Outcomes

Allopurinol is a relatively safe drug that has been used for over half a century. Still, recent studies in gout have shown significant underutilization of this agent and suboptimal dose use, insufficient to reach target serum uric acid concentrations in a considerable proportion of gout patients. A problem with allopurinol treatment for gout is therapy adherence. Emad Y. et al. found that the most common reason for lack of patient adherence to pharmacotherapy is: “patients wanting to lead a normal life.”[17] This is an opportunity for healthcare professionals to improve pharmacotherapy adherence.

Contrary to the common belief, recent studies have shown that allopurinol is safe in severe chronic kidney disease and can impede the progression of renal disease in patients with gout and chronic kidney disease.[18][19] Using allopurinol in patients with gout is also associated with lower all-cause mortality and other adverse cardiovascular events, including readmissions due to congestive heart failure.[19][20][21][22] American College of Rheumatology recommends allopurinol as one of the first-line agents of urate-lowering therapy for gout management.  Several studies report that allopurinol reduced cardiovascular events. However, research by Suissa S. et al. concludes that these studies contained time-related biases and, thus, allopurinol does not provide cardiovascular protection.[23]

There are, however, potential rare though severe adverse effects associated with allopurinol. The use of allopurinol requires management by an interprofessional healthcare team that includes clinicians (MDs, DOs, NPs, PAs), nurses, and pharmacists. Clinicians initiating allopurinol therapy should ensure no drug interactions and that xanthine oxidase inhibitor therapy is the optimal choice; if necessary, a pharmacist consult can assist in this evaluation. Pharmacists can also verify dosing and provide additional patient counsel regarding how to take the drug. The nursing team shall assist with verifying patient adherence and helping to monitor for adverse events and therapeutic effectiveness. All team members should document their observations in the patient’s permanent health record, and be prepared to reach out to other team members when necessary, so alterations to the therapeutic regimen can be made. The best chance for allopurinol to have therapeutic success with minimal adverse events is via an interprofessional team approach. [Level 5]

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References

1.

Khanna D, Fitzgerald JD, Khanna PP, Bae S, Singh MK, Neogi T, Pillinger MH, Merill J, Lee S, Prakash S, Kaldas M, Gogia M, Perez-Ruiz F, Taylor W, Lioté F, Choi H, Singh JA, Dalbeth N, Kaplan S, Niyyar V, Jones D, Yarows SA, Roessler B, Kerr G, King C, Levy G, Furst DE, Edwards NL, Mandell B, Schumacher HR, Robbins M, Wenger N, Terkeltaub R., American College of Rheumatology. 2012 American College of Rheumatology guidelines for management of gout. Part 1: systematic nonpharmacologic and pharmacologic therapeutic approaches to hyperuricemia. Arthritis Care Res (Hoboken). 2012 Oct;64(10):1431-46. [PMC free article: PMC3683400] [PubMed: 23024028]

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van Liere ELSA, Bayoumy AB, Mulder CJJ, Warner B, Hayee B, Mateen BA, Nolan JD, de Boer NKH, Anderson SHC, Ansari AR. Azathioprine with Allopurinol Is a Promising First-Line Therapy for Inflammatory Bowel Diseases. Dig Dis Sci. 2022 Aug;67(8):4008-4019. [PMC free article: PMC9287424] [PubMed: 34729677]

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Schmidt AP, de Oliveira ED, Fagundes AC, Hansel G, Pedrini RO, Valdameri A, Martinelli ES, Schmidt SRG, Andrade CF, Lara DR, Souza DO. Allopurinol attenuates postoperative pain and modulates the purinergic system in patients undergoing abdominal hysterectomy: a randomized controlled trial. J Anesth. 2021 Dec;35(6):818-826. [PubMed: 34390392]

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Fagundes AC, Souza DO, Schmidt AP. Effects of allopurinol on pain and anxiety in fibromyalgia patients: a pilot study. Braz J Anesthesiol. 2021 Nov-Dec;71(6):660-663. [PMC free article: PMC9373309] [PubMed: 34715996]

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Fagundes AC, de Oliveira ED, Ferrari SG, Dos Santos LMM, Botelho LM, Schmidt SRG, Andrade CF, Lara DR, Souza DO, Schmidt AP. Allopurinol for fibromyalgia pain in adults: A randomized controlled trial. Pain Pract. 2022 Jan;22(1):19-27. [PubMed: 33864725]

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Hsu FG, Lai JN, Huang CY, Lin MC, Hsieh YW. Exploring the Relationship Between Colorectal Cancer and Allopurinol: A Taiwanese Population-Based Propensity-Matched Case-Control Study. J Clin Pharmacol. 2021 Aug;61(8):1131-1137. [PubMed: 33580545]

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Park S, Lee JP, Kim DK, Kim YS, Lim CS. Superior effect of allopurinol compared to febuxostat on the retardation of chronic kidney disease progression. PLoS One. 2022;17(2):e0264627. [PMC free article: PMC8884483] [PubMed: 35226683]

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Prieto-Moure B, Cejalvo-Lapeña D, Belda-Antolí M, Padrón-Sanz C, Lloris-Cejalvo JM, Lloris-Carsí JM. Combination Therapy of Allopurinol and Dantrolene and Its Role In The Prevention of Experimental Ischemia Reperfusion Injury Of The Small Intestine. J Invest Surg. 2021 Jul;34(7):800-807. [PubMed: 31906750]

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Stamp LK, O’Donnell JL, Zhang M, James J, Frampton C, Barclay ML, Chapman PT. Using allopurinol above the dose based on creatinine clearance is effective and safe in patients with chronic gout, including those with renal impairment. Arthritis Rheum. 2011 Feb;63(2):412-21. [PubMed: 21279998]

10.

Khanna D, Khanna PP, Fitzgerald JD, Singh MK, Bae S, Neogi T, Pillinger MH, Merill J, Lee S, Prakash S, Kaldas M, Gogia M, Perez-Ruiz F, Taylor W, Lioté F, Choi H, Singh JA, Dalbeth N, Kaplan S, Niyyar V, Jones D, Yarows SA, Roessler B, Kerr G, King C, Levy G, Furst DE, Edwards NL, Mandell B, Schumacher HR, Robbins M, Wenger N, Terkeltaub R., American College of Rheumatology. 2012 American College of Rheumatology guidelines for management of gout. Part 2: therapy and antiinflammatory prophylaxis of acute gouty arthritis. Arthritis Care Res (Hoboken). 2012 Oct;64(10):1447-61. [PMC free article: PMC3662546] [PubMed: 23024029]

11.

Fontana RJ, Li YJ, Phillips E, Saeed N, Barnhart H, Kleiner D, Hoofnagle J., Drug Induced Liver Injury Network. Allopurinol hepatotoxicity is associated with human leukocyte antigen Class I alleles. Liver Int. 2021 Aug;41(8):1884-1893. [PMC free article: PMC8286350] [PubMed: 33899326]

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Choi W, Yang YS, Chang DJ, Chung YW, Kim H, Ko SJ, Yoo S, Oh JS, Kang DY, Yang HJ, Choi IY. Association between the use of allopurinol and risk of increased thyroid-stimulating hormone level. Sci Rep. 2021 Oct 13;11(1):20305. [PMC free article: PMC8514499] [PubMed: 34645831]

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Hoyer D, Atti C, Nuding S, Vogt A, Sedding DG, Schott A. Toxic Epidermal Necrolysis Caused by Allopurinol: A Serious but Still Underestimated Adverse Reaction. Am J Case Rep. 2021 Oct 11;22:e932921. [PMC free article: PMC8522529] [PubMed: 34634004]

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Wong CS, Yeung CK, Chan CY, Yap DY, Tang SC, Cheung BM, Kwok JS, Chan HH. HLA-B*58:01 screening to prevent allopurinol-induced severe cutaneous adverse reactions in Chinese patients with chronic kidney disease. Arch Dermatol Res. 2022 Sep;314(7):651-659. [PubMed: 34213582]

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Lavu A, Thiriveedi S, Thomas L, Khera K, Saravu K, Rao M. Clinical Utility of HLA-B*58:01 Genotyping to Prevent Allopurinol-Induced SJS/TEN. Hosp Pharm. 2021 Dec;56(6):660-663. [PMC free article: PMC8559029] [PubMed: 34732918]

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Drugs and Lactation Database (LactMed®) [Internet]. National Institute of Child Health and Human Development; Bethesda (MD): Mar 21, 2022. Allopurinol. [PubMed: 30000257]

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Emad Y, Dalbeth N, Weinman J, Chalder T, Petrie KJ. Why Do Patients With Gout Not Take Allopurinol? J Rheumatol. 2022 Jun;49(6):622-626. [PubMed: 35169055]

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Siu YP, Leung KT, Tong MK, Kwan TH. Use of allopurinol in slowing the progression of renal disease through its ability to lower serum uric acid level. Am J Kidney Dis. 2006 Jan;47(1):51-9. [PubMed: 16377385]

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Goicoechea M, Garcia de Vinuesa S, Verdalles U, Verde E, Macias N, Santos A, Pérez de Jose A, Cedeño S, Linares T, Luño J. Allopurinol and progression of CKD and cardiovascular events: long-term follow-up of a randomized clinical trial. Am J Kidney Dis. 2015 Apr;65(4):543-9. [PubMed: 25595565]

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Luk AJ, Levin GP, Moore EE, Zhou XH, Kestenbaum BR, Choi HK. Allopurinol and mortality in hyperuricaemic patients. Rheumatology (Oxford). 2009 Jul;48(7):804-6. [PMC free article: PMC4481712] [PubMed: 19447769]

21.

Thanassoulis G, Brophy JM, Richard H, Pilote L. Gout, allopurinol use, and heart failure outcomes. Arch Intern Med. 2010 Aug 09;170(15):1358-64. [PubMed: 20696962]

22.

Struthers AD, Donnan PT, Lindsay P, McNaughton D, Broomhall J, MacDonald TM. Effect of allopurinol on mortality and hospitalisations in chronic heart failure: a retrospective cohort study. Heart. 2002 Mar;87(3):229-34. [PMC free article: PMC1767024] [PubMed: 11847159]

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Suissa S, Suissa K, Hudson M. Allopurinol and Cardiovascular Events: Time-Related Biases in Observational Studies. Arthritis Care Res (Hoboken). 2022 May;74(5):858-865. [PubMed: 34057310]

Disclosure: Ahmad Qurie declares no relevant financial relationships with ineligible companies.

Disclosure: Charles Preuss declares no relevant financial relationships with ineligible companies.

Disclosure: Rina Musa declares no relevant financial relationships with ineligible companies.

Allopurinol instructions for use: indications, contraindications, side effects – description of Allopurinol tab. 100 mg: 50 pcs. (22497)

The use of allopurinol in the treatment of children with cancer

Supportive care

Trademarks:

Aloprim®, Zyloprim®

Other names:

Allopurinol sodium

Often used for:

treatment of high blood uric acid (hyperuricemia)

Allopurinol is prescribed to lower blood uric acid. High levels of uric acid in the blood can be caused by certain cancer medications. Too much uric acid can lead to attacks of gout or kidney stones. The introduction of allopurinol may be required in patients who develop tumor lysis syndrome as a result of antitumor therapy. Therapy with this drug can be done in a clinic, hospital, or outpatient setting.

Oral tablets

Administered intravenously (through a drip) in liquid form

Oral liquid form

• Skin irritation, rash
• Drowsiness
• Headache
• Nausea and vomiting
• Flu-like symptoms (chills, aches, fever)
• Pain in muscles or joints
• Sudden decrease in the amount of urine, pain when urinating, blood in the urine
• Labored breathing
• Yellowing of the skin or whites of the eyes
• Diarrhea

The listed side effects are not observed in all patients who are prescribed allopurinol. The most common side effects are highlighted in bold, but others are not excluded. Report all possible side effects to your doctor or pharmacist.

Be sure to discuss these and other recommendations with your doctor or pharmacist.

• Tell your doctor or nurse immediately if you experience pain or irritation at the injection site when allopurinol is given intravenously.
• It is important to drink plenty of fluids during therapy with allopurinol. It is necessary to drink the amount of liquid recommended by the doctor. During therapy with allopurinol, family members should keep a diary of the amount of water drunk by the patient and the frequency of urination.
• Antacids (eg, ranitidine) should be avoided during treatment with allopurinol unless this type of drug is prescribed by a healthcare professional.
• Pregnant or breastfeeding patients should notify their physician.

Allopurinol home use:

• To avoid nausea and vomiting, take allopurinol with or immediately after meals.