Side Effects of Zyloprim (Allopurinol), Warnings, Uses (2022)


Data upon which the following estimates of incidence of adverse reactions are made are derived from experiences reported in the literature, unpublished clinical trials and voluntary reports since marketing of ZYLOPRIM (allopurinol) began. Past experience suggested that the most frequent event following the initiation of allopurinol treatment was an increase in acute attacks of gout (average 6% in early studies). An analysis of current usage suggests that the incidence of acute gouty attacks has diminished to less than 1%. The explanation for this decrease has not been determined but may be due in part to initiating therapy more gradually (see PRECAUTIONS and DOSAGE AND ADMINISTRATION).

The most frequent adverse reaction to ZYLOPRIM is skin rash. Skin reactions can be severe and sometimes fatal. Therefore, treatment with ZYLOPRIM should be discontinued immediately if a rash develops (see WARNINGS). Some patients with the most severe reaction also had fever, chills, arthralgias, cholestatic jaundice, eosinophilia and mild leukocytosis or leukopenia. Among 55 patients with gout treated with ZYLOPRIM for 3 to 34 months (average greater than 1 year) and followed prospectively, Rundles observed that 3% of patients developed a type of drug reaction which was predominantly a pruritic maculopapular skin eruption, sometimes scaly or exfoliative. However, with current usage, skin reactions have been observed less frequently than 1%. The explanation for this decrease is not obvious. The incidence of skin rash may be increased in the presence of renal insufficiency. The frequency of skin rash among patients receiving ampicillin or amoxicillin concurrently with ZYLOPRIM has been reported to be increased (see PRECAUTIONS).

Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome or drug hypersensitivity syndrome (DHS) has been reported in association with allopurinol use. The syndrome includes many of the severe reactions described above, and is potentially life-threatening and fatal. The syndrome is often characterized by fever, severe and profuse skin rash, elevated leukocyte counts and in particular, elevated eosinophil counts, lymphadenopathy, and multi-organ pathologies. Systemic symptoms often included, but were not limited to, the hepatic and renal systems. Symptoms involving the cardiac, gastrointestinal, lymphatic, pulmonary, and ophthalmic systems were also reported as occurring as part of the syndrome. It has been reported that symptoms may develop in approximately 1 week from initiating allopurinol therapy, but longer latency periods have also been reported.

To report SUSPECTED ADVERSE REACTIONS, contact Casper Pharma LLC at 1-844-5­CASPER (1-844-522-7737) or FDA at 1-800-FDA-1088 or

Most Common Reactions* Probably Causally Related

Gastrointestinal: Diarrhea, nausea, alkaline phosphatase increase, SGOT/SGPT increase.

Metabolic and Nutritional: Acute attacks of gout.

Skin and Appendages: Rash, maculopapular rash.

*Early clinical studies and incidence rates from early clinical experience with ZYLOPRIM suggested that these adverse reactions were found to occur at a rate of greater than 1%. The most frequent event observed was acute attacks of gout following the initiation of therapy. Analyses of current usage suggest that the incidence of these adverse reactions is now less than 1%. The explanation for this decrease has not been determined, but it may be due to following recommended usage (see ADVERSE REACTIONS introduction, INDICATIONS AND USAGE, PRECAUTIONS, and DOSAGE AND ADMINISTRATION).

(Video) Allopurinol Side Effects - What You Need To Know Now

Incidence Less Than 1% Probably Causally Related

Body As a Whole: Ecchymosis, fever, headache.

Cardiovascular: Necrotizing angiitis, vasculitis.

Gastrointestinal: Hepatic necrosis, granulomatous hepatitis, hepatomegaly, hyperbilirubinemia, cholestatic jaundice, vomiting, intermittent abdominal pain, gastritis, dyspepsia.

Hemic and Lymphatic: Thrombocytopenia, eosinophilia, leukocytosis, leukopenia.

Musculoskeletal: Myopathy, arthralgias.

Nervous: Peripheral neuropathy, neuritis, paresthesia, somnolence.

Respiratory: Epistaxis.

Skin and Appendages: Erythema multiforme exudativum (Stevens-Johnson syndrome), toxic epidermal necrolysis (Lyell's syndrome), hypersensitivity vasculitis, purpura, vesicular bullous dermatitis, exfoliative dermatitis, eczematoid dermatitis, pruritus, urticaria, alopecia, onycholysis, lichen planus.

(Video) Allopurinol (Zyloprim) - Uses, Dosing, Side Effects

Special Senses: Taste loss/perversion.

Urogenital: Renal failure, uremia (see PRECAUTIONS).

Incidence Less Than 1% Causal Relationship Unknown

Body As a Whole: Malaise.

Cardiovascular: Pericarditis, peripheral vascular disease, thrombophlebitis, bradycardia, vasodilation.

Endocrine: Infertility (male), hypercalcemia, gynecomastia (male).

Gastrointestinal: Hemorrhagic pancreatitis, gastrointestinal bleeding, stomatitis, salivary gland swelling, hyperlipidemia, tongue edema, anorexia.

Hemic and Lymphatic: Aplastic anemia, agranulocytosis, eosinophilic fibrohistiocytic lesion of bone marrow, pancytopenia, prothrombin decrease, anemia, hemolytic anemia, reticulocytosis, lymphadenopathy, lymphocytosis.

Musculoskeletal: Myalgia.

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Nervous: Optic neuritis, confusion, dizziness, vertigo, foot drop, decrease in libido, depression, amnesia, tinnitus, asthenia, insomnia.

Respiratory: Bronchospasm, asthma, pharyngitis, rhinitis.

Skin and Appendages: Furunculosis, facial edema, sweating, skin edema.

Special Senses: Cataracts, macular retinitis, iritis, conjunctivitis, amblyopia.

Urogenital: Nephritis, impotence, primary hematuria, albuminuria.


In patients receiving mercaptopurine or IMURAN (azathioprine), the concomitant administration of 300 to 600 mg of ZYLOPRIM per day will require a reduction in dose to approximately one third to one fourth of the usual dose of mercaptopurine or azathioprine. Subsequent adjustment of doses of mercaptopurine or azathioprine should be made on the basis of therapeutic response and the appearance of toxic effects (see CLINICAL PHARMACOLOGY).

It has been reported that ZYLOPRIM prolongs the half-life of the anticoagulant, dicumarol. The clinical basis of this drug interaction has not been established but should be noted when ZYLOPRIM is given to patients already on dicumarol therapy.

Since the excretion of oxipurinol is similar to that of urate, uricosuric agents, which increase the excretion of urate, are also likely to increase the excretion of oxipurinol and thus lower the degree of inhibition of xanthine oxidase. The concomitant administration of uricosuric agents and ZYLOPRIM has been associated with a decrease in the excretion of oxypurines (hypoxanthine and xanthine) and an increase in urinary uric acid excretion compared with that observed with ZYLOPRIM alone. Although clinical evidence to date has not demonstrated renal precipitation of oxypurines in patients either on ZYLOPRIM alone or in combination with uricosuric agents, the possibility should be kept in mind.

(Video) Allopurinol for Gout 100 mg, 300 mg Dosage and Side Effects

The reports that the concomitant use of ZYLOPRIM and thiazide diuretics may contribute to the enhancement of allopurinol toxicity in some patients have been reviewed in an attempt to establish a cause-and-effect relationship and a mechanism of causation. Review of these case reports indicates that the patients were mainly receiving thiazide diuretics for hypertension and that tests to rule out decreased renal function secondary to hypertensive nephropathy were not often performed. In those patients in whom renal insufficiency was documented, however, the recommendation to lower the dose of ZYLOPRIM was not followed. Although a causal mechanism and a cause-and-effect relationship have not been established, current evidence suggests that renal function should be monitored in patients on thiazide diuretics and ZYLOPRIM even in the absence of renal failure, and dosage levels should be even more conservatively adjusted in those patients on such combined therapy if diminished renal function is detected.

An increase in the frequency of skin rash has been reported among patients receiving ampicillin or amoxicillin concurrently with ZYLOPRIM compared to patients who are not receiving both drugs. The cause of the reported association has not been established.

Enhanced bone marrow suppression by cyclophosphamide and other cytotoxic agents has been reported among patients with neoplastic disease, except leukemia, in the presence of ZYLOPRIM. However, in a well-controlled study of patients with lymphoma on combination therapy, ZYLOPRIM did not increase the marrow toxicity of patients treated with cyclophosphamide, doxorubicin, bleomycin, procarbazine, and/or mechlorethamine.

Tolbutamide's conversion to inactive metabolites has been shown to be catalyzed by xanthine oxidase from rat liver. The clinical significance, if any, of these observations is unknown.

Chlorpropamide's plasma half-life may be prolonged by ZYLOPRIM, since ZYLOPRIM and chlorpropamide may compete for excretion in the renal tubule. The risk of hypoglycemia secondary to this mechanism may be increased if ZYLOPRIM and chlorpropamide are given concomitantly in the presence of renal insufficiency.

Rare reports indicate that cyclosporine levels may be increased during concomitant treatment with ZYLOPRIM. Monitoring of cyclosporine levels and possible adjustment of cyclosporine dosage should be considered when these drugs are co-administered.

Drug/Laboratory Test Interactions

ZYLOPRIM is not known to alter the accuracy of laboratory tests.

Read the entire FDA prescribing information for Zyloprim (Allopurinol)

(Video) Allopurinol | Uses, Side Effects & Pecautions

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Which of the following is a common side effect of allopurinol? ›

The more common side effects of allopurinol oral tablet can include: skin rash. diarrhea. nausea.

What is allopurinol zyloprim used for? ›

Allopurinol is used to prevent or lower high uric acid levels in the blood. It is also used to prevent or lower excess uric acid levels caused by cancer medicines or in patients with kidney stones. A high uric acid level can cause gout or gouty arthritis (joint pain and inflammation).

What foods to avoid while taking allopurinol? ›

Foods to avoid
  • red meats, such as beef, pork, and lamb.
  • organ meats, including liver and kidneys.
  • seafood, such as mussels, scallops, anchovies, sardines, trout, and tuna.
  • alcohol, especially beer.
31 May 2019

What drugs should not be taken with allopurinol? ›

Serious Interactions of Allopurinol include:
  • azathioprine.
  • benazepril.
  • captopril.
  • didanosine.
  • dyphylline.
  • enalapril.
  • perindopril.
  • protamine.

Is allopurinol a high risk medication? ›

Although generally safe and well-tolerated, allopurinol has been associated with severe cutaneous adverse reactions, including Stevens–Johnson syndrome and toxic epidermal necrolysis, which are collectively referred to as allopurinol-associated severe cutaneous adverse reactions.

Does allopurinol cause memory loss? ›

Amnesia, agitation, and insomnia were reported in less than 1% of patients.

Can allopurinol affect your eyes? ›

The National Registry of Drug Induced Ocular Side Effects in the US published 30 case histories of cataract suspected to be induced by allopurinol; numerous additional cases have been reported to the registry since.

What time of day is best to take allopurinol? ›

Allopurinol comes as a tablet to take by mouth. It is usually taken once or twice a day, preferably after a meal. To help you remember to take allopurinol, take it around the same time every day.

Does allopurinol affect urination? ›

Discontinue allopurinol at the first appearance of a skin rash, painful urination, blood in the urine, eye irritation, or facial swelling, and seek urgent medical advice.

Does allopurinol raise blood pressure? ›

A meta-analysis of the effect of allopurinol on BP, combining data from 10 clinical studies with 738 participants, found a small reduction in BP in allopurinol-treated patients (3.3 mm Hg; 95% confidence interval [CI], −1.4 to −5.3 mm Hg) for systolic BP.

Does allopurinol affect the heart? ›

Small clinical studies with allopurinol have demonstrated improvements in cardiac function,20,21 reductions in endothelial dysfunction,22,23 reductions in oxidative stress,24 and improvements in surrogate outcomes among HF patients.

When should you not take allopurinol? ›

Who should not take Allopurinol?
  • dehydration.
  • anemia.
  • decreased blood platelets.
  • low levels of white blood cells.
  • abnormal liver function tests.
  • chronic kidney disease stage 4 (severe)
  • chronic kidney disease stage 5 (failure)
  • kidney disease with likely reduction in kidney function.

What kills uric acid in the body? ›

Vegetables like bottle gourd, ash gourd, pumpkin and zucchini are effective natural treatments for lowering blood uric acid levels. Foods high in protein, such as red meat, chicken, sardines, shellfish and mackerel, can be avoided. Tofu, soybeans and other soy products should ideally not be preferred for consumption.

Is Bananas good for gout? ›

Bananas are low in purines and high in vitamin C, which makes them a good food to eat if you have gout. Changing your diet to include more low-purine foods, like bananas, can lower the amount of uric acid in your blood and reduce your risk of recurrent gout attacks.

Is Egg good for uric acid? ›

Certain foods, such as red meat, are rich in purines. You should avoid such foods if you have gout or are at a high risk for it. This means you need to choose sources of protein that are low in purines. Eggs are a good option.

What fruits are not good for gout? ›

Fruit, Fructose, and Gout

Researchers report a correlation between foods high in fructose and gout symptoms, which can include chronic pain. These fruits include apples, peaches, pears, plums, grapes, prunes, and dates.

What does allopurinol do to your kidneys? ›

Allopurinol decreases serum UA level by inhibiting the enzyme xanthine oxidase. For animal models of established renal diseases, correction of the hyperuricemic state can significantly improve BP control, decreasing proteinuria and slowing the progression of renal disease (4).

How long should patients be on allopurinol? ›

Remember, allopurinol should be taken every day to prevent a gout attack. It can take 2-3 months to become fully effective. It does not have any effect during a gout attack, although you should continue to take it regularly every day even if this happens.

Why do you need to drink water with allopurinol? ›

Take this medicine with plenty of liquids to help prevent kidney stones. Check with your doctor about the amount of liquid you should drink each day. You should also increase your fiber intake.

Can allopurinol cause a stroke? ›

Yet another study of gout patients using Scottish database reported that compared to non-use, allopurinol use was associated with higher (not lower) adjusted hazards of cardiovascular hospitalization (including coronary artery disease (CAD), hypertensive heart disease, heart failure, stroke, other cardiovascular ...

Why should you not stop taking allopurinol? ›

You should keep taking allopurinol even if: you are experiencing more gout attacks, or it doesn't seem to help the pain and inflammation at first. you stop having gout attacks – stopping your treatment can cause urate crystals to form again, which will lead to more gout attacks.

Is there a better medication than allopurinol? ›

Allopurinol didn't work for you: If allopurinol can't lower your uric acid level to less than 6 mg/dL, then experts recommend switching to another medication — like febuxostat.

Can you suddenly stop taking allopurinol? ›

Do not stop taking allopurinol suddenly unless you have a skin rash or allergic reaction. Speak to your doctor or nurse before stopping. Stopping allopurinol quickly can cause a flare up and make your gout worse.

Does allopurinol thin hair? ›

Gout medications like allopurinol (Zyloprim and Lopurin) have been reported to cause hair loss.

Does allopurinol cause brain fog? ›

Side effects associated with medication reported by participants were: (1) allopurinol: nausea, allergic reaction, itching, rash, headache, or brain fog; (2) colchicine: problems with calcium levels, kidney function, diverticulitis, brain fog, dry mouth, stomach upset, or sun sensitivity; (3) non-steroidal anti- ...

What is the best thing to drink if you have gout? ›

Drinking plenty of water is best if you have gout. Other beverages recommended for gout patients include milk, tart cherry juice, and coffee—all in moderation.

What time of day is uric acid highest? ›

The risk of gout flares in the first 8 hours of the day (12:00 am to 7:59 am) was 2.36 times higher than in the daytime (8:00 am to 3:59 pm) (OR 2.36 [95% CI 2.05–2.73]).

Does allopurinol make you pee alot? ›

symptoms of increased blood pressure (e.g., chest pain, blurred vision, dizziness, excessive tiredness, headache, fast or racing heartbeat) symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)

Is allopurinol hard on kidneys? ›

Acute renal failure was reported significantly more frequently for febuxostat and allopurinol than for other drugs (ROR [95%CI] 5.67 [5.05–6.36] and 3.25 [3.05–3.47], respectively).

Will allopurinol raise blood sugar? ›

Based on several biological and clinical observations, recent studies suggest that allopurinol use may be associated with improved insulin sensitivity and blood glucose levels.

Can you live a long life with gout? ›

If diagnosed early, most people with gout can live a normal life. If your disease has advanced, lowering your uric acid level can improve joint function and resolve tophi. Medication and lifestyle or dietary changes can also help ease symptoms and reduce the frequency and severity of gout attacks.

What causes high uric acid? ›

Most of the time, a high uric acid level occurs when your kidneys don't eliminate uric acid efficiently. Things that may cause this slow-down in the removal of uric acid include rich foods, being overweight, having diabetes, taking certain diuretics (sometimes called water pills) and drinking too much alcohol.

Is lemon good for uric acid? ›

Lemon juice may help balance uric acid levels because it helps make the body more alkaline. This means it slightly raises the pH level of blood and other fluids. Lemon juice also makes your urine more alkaline.

Is uric acid can cause death? ›

In the overall study population, a high blood uric acid level was associated with a statistically significant increased risk of death from cardiovascular disease, stroke, congestive heart failure or any cause.

Can uric acid be totally cured? ›

Gout is one of the most common inflammatory arthritides. The disease is due to the deposition of monosodium urate crystals. These deposits are reversible with proper treatment, suggesting that gout is a curable disease.

What kills uric acid in the body naturally? ›

What makes uric acid go down?
  • Restrict purine-rich foods.
  • Avoid alcohol and sugar.
  • Stay hydrated.
  • Manage blood sugar.
  • Lose weight.
  • Consume fibre-rich foods.
9 Nov 2022

Is banana good for uric acid? ›

Bananas are low in purines and high in vitamin C, which makes them a good food to eat if you have gout. Changing your diet to include more low-purine foods, like bananas, can lower the amount of uric acid in your blood and reduce your risk of recurrent gout attacks.

What food removes uric acid? ›

The following foods may help to ease gout by lowering uric acid levels or reducing purine intake:
  • Cherries.
  • Foods high in vitamin C (e.g., oranges, spinach, kale)
  • Coffee.
  • Low-purine foods (e.g., whole grains, vegetables, plant-based protein like nuts and legumes)
  • Low-fat dairy.
  • Water.
10 Oct 2022

Can you take allopurinol for years? ›

Allopurinol doesn't treat the immediate pain caused by attacks of gout. But it's a long-term treatment to get rid of the urate crystals which causes gout attacks. It is likely that you will need to take allopurinol for the rest of your life to manage your urate levels.

Is allopurinol hard on the kidneys? ›

Acute renal failure was reported significantly more frequently for febuxostat and allopurinol than for other drugs (ROR [95%CI] 5.67 [5.05–6.36] and 3.25 [3.05–3.47], respectively).

Is lemon water good for gout? ›

The studies concluded that lemons and lemon juice might be a useful remedy to help treat gout, along with medications and other dietary changes. Lemon juice may also help prevent gout in people with high uric acid levels.

Can drinking lots of water stop gout? ›

You can also help reduce the number of gout attacks you have by drinking plenty of fluids, especially water, but you should avoid drinks sweetened by sugar or too much fruit juice as these can trigger an attack. Diet drinks are fine.


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