Allopurinol Sodium

Allopurinol Sodium for Injection is indicated for the management of adult and pediatric patients with leukemia, lymphoma, and solid tumor malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels and who cannot tolerate oral therapy. Allopurinol Sodium for Injection is a xanthine oxidase inhibitor indicated for the management of adult and pediatric patients with leukemia, lymphoma, and solid tumor malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels and who cannot tolerate oral therapy. ( 1 )

For Injection: 500 mg of allopurinol as a sterile, white lyophilized powder or cake in a single-dose vial for reconstitution. For injection: 500 mg as a white lyophilized powder or cake in a single-dose vial for reconstitution ( 3 )

Allopurinol Sodium for Injection is contraindicated in patients with a history of severe reaction to any formulation of allopurinol. Known hypersensitivity to allopurinol. ( 4 )

Skin Rash and Hypersensitivity: Discontinue Allopurinol Sodium for Injection at the first appearance of skin rash or other signs which may indicate a hypersensitivity reaction. Allopurinol has been associated with serious and sometimes fatal dermatologic reactions. ( 5.1 ) Renal Function Impairment: Patients with decreased renal function require lower doses of allopurinol. ( 5.2 ) Hepatotoxicity: If signs and symptoms of hepatotoxicity develop, liver function evaluation should be performed. ( 5.3 ) Myelosuppression: Bone marrow suppression has been reported with allopurinol. ( 5.4 ) Drowsiness: Drowsiness has been reported in patients taking Allopurinol Sodium for Injection. ( 5.5 )

5.1 Skin Rash and Hypersensitivity Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), and drug reaction with eosinophilia and systemic symptoms (DRESS) have been reported in patients taking allopurinol [see Adverse Reactions (6.1) ] . These reactions occur in approximately 5 in 10,000 (0.05%) patients taking allopurinol. Other serious hypersensitivity reactions that have been reported include exfoliative, urticarial and purpuric lesions; generalized vasculitis; and irreversible hepatotoxicity. Discontinue Allopurinol Sodium for Injection at the first appearance of skin rash or other signs which may indicate a hypersensitivity reaction. The HLA-B*58:01 allele is a genetic marker for severe skin reactions indicative of hypersensitivity to allopurinol. Patients who carry the HLA-B*58:01 allele are at a higher risk of allopurinol hypersensitivity syndrome (AHS), but hypersensitivity reactions have been reported in patients who do not carry this allele. The frequency of this allele is higher in individuals of African, Asian (e.g., Han Chinese, Korean, Thai), and Native Hawaiian/Pacific Islander ancestry [see Clinical Pharmacology (12.5) ] . The use of Allopurinol Sodium for Injection is not recommended in HLA-B*58:01 positive patients unless the benefits clearly outweigh the risks. Prior to starting Allopurinol Sodium for Injection, consider testing for the HLA-B*58:01 allele in genetically at-risk populations. Screening is generally not recommended in patients from populations in which the prevalence of HLA-B*58:01 is low, or in current allopurinol users, as the risk of SJS/TEN/DRESS is largely confined to the first few months of therapy, regardless of HLA-B*58:01 status. Hypersensitivity reactions to Allopurinol Sodium for Injection may be increased in patients with decreased renal function receiving thiazide diuretics and Allopurinol Sodium for Injection concurrently. In addition, concomitant use of the following drugs may increase the risk of skin rash, which may be severe: bendamustine, thiazide diuretics, ampicillin and amoxicillin [see Drug Interactions (7.1) ] . Patients should stop Allopurinol Sodium for Injection and seek medical attention if they develop a rash.

5.2 Renal Function Impairment Treatment with Allopurinol Sodium for Injection may result in renal impairment due to formation of xanthine calculi or due to precipitation of urates in patients receiving concomitant uricosuric agents. Patients with pre-existing renal disease, including renal impairment or history of kidney stones, may be at increased risk for worsening renal impairment due to xanthine calculi or precipitation of urates while receiving treatment with Allopurinol Sodium for Injection. Monitor serum creatinine at least daily during the early stages of allopurinol administration. Maintain fluid intake sufficient to yield a urinary output of at least 2 liters per day in adults. In patients with severely impaired renal function or increase in uric acid concentration associated with decreased urate clearance, reduce the dosage of Allopurinol Sodium for Injection [see Use In Specific Populations (8.6) and Dosage and Administration (2.1 , 2.2) ] .

5.3 Hepatotoxicity Cases of reversible clinical hepatotoxicity have been noted in patients taking oral allopurinol. In some patients, asymptomatic rises in serum alkaline phosphatase or serum transaminase have been observed. If anorexia, weight loss, or pruritus develop in patients on allopurinol, evaluate liver enzymes. In patients with pre-existing liver disease, monitor liver enzymes periodically during the early stages of therapy. Discontinue Allopurinol Sodium for Injection in patients with elevated liver enzymes.

5.4 Myelosuppression Myelosuppression, manifested by anemia, leukopenia or thrombocytopenia, has been reported in patients receiving allopurinol [see Adverse Reactions (6.1) ] . The cytopenias have occurred from as early as 6 weeks to as late as 6 years after the initiation of allopurinol therapy. Discontinue use of Allopurinol Sodium for Injection in patients with unexplained cytopenias. Concomitant use with allopurinol with cytotoxic drugs associated with myelosuppression may increase the risk of myelosuppression. Monitor blood counts more frequently [see Drug Interactions (7) ] . Concomitant use with allopurinol increases the exposure of either mercaptopurine or azathioprine which may increase the risk of myelosuppression. Reduce the dosage of mercaptopurine or azathioprine as recommended in the respective prescribing information when used concomitantly with Allopurinol Sodium for Injection. [see Drug Interactions (7) ] .

5.5 Drowsiness Drowsiness has been reported in patients taking Allopurinol Sodium for Injection [see Adverse Reactions (6.1) ] . Advise patients to avoid operation of automobiles or other dangerous machinery and activities made hazardous by decreased alertness when starting Allopurinol Sodium for Injection or increasing the dose until they know how the drug affects them. Advise patients that the central nervous system depressant effects of Allopurinol Sodium for Injection may be additive to those of alcohol and other CNS depressants.

The following clinically significant adverse reactions are described elsewhere in the labeling: Skin Rash and Hypersensitivity [see Warnings and Precautions (5.1) ] Renal Function Impairment [see Warnings and Precautions (5.2) ] Hepatoxicity [see Warnings and Precautions (5.3) ] Myelosuppression [see Warnings and Precautions (5.4) ] Drowsiness [see Warnings and Precautions (5.5) ] Most common adverse reactions (incidence > 1%) are skin rash, nausea, vomiting, and renal failure/insufficiency. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Hikma Pharmaceuticals USA Inc. at 1-877-845-0689 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of Allopurinol Sodium for Injection was evaluated in an uncontrolled compassionate use study of 1,378 patients with advanced malignancies requiring treatment with cytotoxic chemotherapy and in patients with other serious conditions. Adverse reactions were reported in 9% (125/1378) of the patients treated with Allopurinol Sodium for Injection. The most common adverse reaction was skin rash. Two patients experience serious adverse reactions (decreased renal function and generalized seizure) and one patient experienced severe diarrhea. Approximately 1.1% of patients experienced allergic adverse reactions (including rash, eosinophilia, local injection site reaction). A listing of the adverse reactions reported from clinical trials follows: Incidence Greater Than 1%: Cutaneous/Dermatologic: rash (1.5%) Genitourinary: renal failure/insufficiency (1.2%) Gastrointestinal: nausea (1.3%), vomiting (1.2%) Incidence Less Than 1%: Body as a Whole: fever, pain, chills, alopecia, infection, sepsis, enlarged abdomen, mucositis/pharyngitis, blast crisis, cellulitis, hypervolemia Cardiovascular: heart failure, cardiorespiratory arrest, hypertension, pulmonary embolus, hypotension, decreased venous pressure, flushing, headache, stroke, septic shock, cardiovascular disorder, ECG abnormality, hemorrhage, bradycardia, thrombophlebitis, ventricular fibrillation Cutaneous/Dermatologic: urticaria, pruritus, local injection site reaction Gastrointestinal: diarrhea, gastrointestinal bleeding, hyperbilirubinemia, splenomegaly, hepatomegaly, intestinal obstruction, jaundice, flatulence, constipation, liver failure, proctitis Genitourinary: hematuria, increased creatinine, oliguria, kidney function abnormality, urinary tract infection Hematologic: leukopenia, marrow aplasia, thrombocytopenia, eosinophilia, neutropenia, anemia, pancytopenia, ecchymosis, bone marrow suppression, disseminated intravascular coagulation Metabolic: hypocalcemia, hyperphosphatemia, hypokalemia, hyperuricemia, electrolyte abnormality, hypercalcemia, hyperglycemia, hypernatremia, hyponatremia, metabolic acidosis, edema, glycosuria, hyperkalemia, lactic acidosis, water intoxication, hypomagnesemia Neurologic: seizure, status epilepticus, myoclonus, twitching, agitation, mental status changes, cerebral infarction, coma, dystonia, paralysis, tremor Pulmonary: respiratory failure/insufficiency, ARDS, increased respiration rate, apnea Musculoskeletal: arthralgia Other: hypotonia, diaphoresis, tumor lysis syndrome

Clinically important interactions with the drugs listed below were observed in patients undergoing treatment with an oral allopurinol formulation. Capecitabine: Avoid the concomitant use of allopurinol ( 7.2 ). Pegloticase: Discontinue and do not institute allopurinol therapy during treatment with pegloticase ( 7.2 ). Mercaptopurine or Azathioprine: Reduce mercaptopurine or azathioprine dose as recommended in the respective prescribing information ( 7.2 ). See full prescribing information for complete list of significant drug interactions ( 7 ).

7.1 Drugs Known to Affect the Occurrence of Skin Rash and Hypersensitivity Concomitant use of the following drugs may increase the risk of skin rash, which may be severe: bendamustine, thiazide diuretics, ampicillin and amoxicillin. Renal impairment may further increase risk with concomitant use of thiazide diuretics [see Warnings and Precautions (5.1) (5.2) and Clinical Pharmacology (12.2) ] . Monitor renal function and reduce the dose of Allopurinol Sodium for Injection in patients with concomitant thiazide diuretic use and impaired renal function [see Dosage and Administration (2.2) ]. Discontinue Allopurinol Sodium for Injection at the first appearance of skin rash or other signs which may indicate a hypersensitivity reaction when use concomitantly with these drugs.

7.2 Other Drugs Known to Have Clinically Important Drug Interactions with Allopurinol Sodium for Injection Table 4: Interventions for Clinically Important Drug Interactions with Allopurinol Sodium for Injection Capecitabine Clinical Impact Concomitant use with allopurinol may decrease concentration of capecitabine’s active metabolites, which may decrease capecitabine efficacy. Intervention Avoid the use of Allopurinol Sodium for Injection during treatment with capecitabine. Cyclosporine Clinical Impact Concomitant use of allopurinol increases cyclosporine concentrations which may increase the risk of adverse reactions. Intervention Increase frequency of monitoring cyclosporine concentrations as reflected in the prescribing information when used concomitantly with Allopurinol Sodium for Injection. Cytotoxic Agents Clinical Impact Concomitant use of allopurinol with cytotoxic agents increases bone marrow suppression among patients with neoplastic disease, except leukemia [see Warnings and Precautions (5.4) and Clinical Pharmacology (12.2) ] . Intervention Blood count monitoring and regular physician follow-up recommended. Fluorouracil Clinical Impact Based on non-clinical data, allopurinol may decrease anti-tumor activity due to suppression of phosphorylation of 5-fluorouracil. Intervention Concomitant administration with fluorouracil should be avoided. Mercaptopurine or Azathioprine Clinical Impact Allopurinol inhibits xanthine oxidase mediated metabolism of mercaptopurine and azathioprine. Concomitant use of allopurinol increases the exposure of either mercaptopurine or azathioprine which may increase the risk of their adverse reactions including myelosuppression [see Warnings and Precautions (5.4) ] . Intervention Reduce the dosage of mercaptopurine or azathioprine as recommended in the respective prescribing information. Pegloticase Clinical Impact Concomitant use of Allopurinol Sodium for Injection and pegloticase may potentially blunt the rise of serum uric acid levels and increase the risk of pegloticase related anaphylaxis in patients whose uric acid level increase to above 6 mg/dL. Intervention Discontinue and do not institute Allopurinol Sodium for Injection therapy during treatment with pegloticase. Theophylline Clinical Impact Concomitant use of allopurinol doses greater than or equal to 600 mg/day may decrease the clearance of theophylline. Intervention Monitor and adjust theophylline doses as reflected in the prescribing information. Uricosuric Agents Clinical Impact Uricosuric agents increase the excretion of the active allopurinol metabolite oxypurinol. Concomitant use with uricosuric agents decreases oxypurinol exposure which may reduce the inhibition of xanthine oxidase by oxypurinol and increases the urinary excretion of uric acid. Intervention Monitor uric acid levels due to the increased chance of hypouricemic effects. Warfarin Clinical Impact Allopurinol may inhibit the metabolism of warfarin, possibly enhancing its anticoagulant effect. Intervention Patients on concomitant therapy should be monitored for excessive anticoagulation. The INR should be checked frequently and warfarin dosage adjusted accordingly when allopurinol is added to warfarin therapy.

Pregnancy: May cause fetal harm ( 8.1 ). Lactation: Advise not to breastfeed ( 8.2 ).

8.1 Pregnancy Risk Summary Based on findings in animals, Allopurinol Sodium for Injection may cause fetal harm when administered to a pregnant woman. Adverse developmental outcomes have been described in exposed animals (see Data ) . Allopurinol and its metabolite oxypurinol have been shown to cross the placenta following administration of maternal allopurinol. Available limited published data on allopurinol use in pregnant women do not demonstrate a clear pattern or increase in frequency of adverse developmental outcomes. Among approximately 50 pregnancies described in published literature, 2 infants with major congenital malformations have been reported with following maternal allopurinol exposure. Advise pregnant women of the potential risk to a fetus. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data There was no evidence of fetotoxicity or teratogenicity in rats or rabbits treated during the period of organogenesis with oral allopurinol at doses up to 200 mg/kg/day and up to 100 mg/kg/day, respectively (about three times the human dose on a mg/m 2 basis). However, there is a published report in pregnant mice that single intraperitoneal doses of 50 or 100 mg/kg (about 1/3 or 3/4 the human dose on a mg/m 2 basis) of allopurinol on gestation days 10 or 13 produced significant increases in fetal deaths and teratogenic effects (cleft palate, harelip, and digital defects). It is uncertain whether these findings represented a fetal effect or an effect secondary to maternal toxicity. In another published study with no reported maternal toxicity, allopurinol administered orally at 15 or 45 mg/kg to pregnant rats during organogenesis caused embryonic resorptions, growth retardation, decreased fetal weight, and skeletal, liver, kidney, and brain abnormalities. In rats, maternal treatment with allopurinol in normoxic pregnancy has been shown to increase the cardiac protein levels of sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2a) in the adult male offspring. The mechanism underlying this effect is not understood. However, this effect was not matched by an increase in left ventricular end diastolic pressure or sympathetic dominance in hearts of adult male offspring of normoxic pregnancy treated with allopurinol.

8.2 Lactation Risk Summary Allopurinol and oxypurinol are present in human milk. Based on information from a single case report, allopurinol and its active metabolite, oxypurinol, were detected in the milk of a mother at five weeks postpartum at an estimated relative infant dose of 0.14 and 0.2 mg/kg of allopurinol and between 7.2 to 8 mg/kg of oxypurinol daily. There was no report of effects of allopurinol on the breastfed infant or on milk production. Because of the potential for serious adverse reactions in a breastfed child, advise women not to breastfeed during treatments with Allopurinol Sodium for Injection and for one week after the last dose.

8.4 Pediatric Use The safety and effectiveness of Allopurinol Sodium for Injection have been established in approximately 200 pediatric patients. The efficacy and safety profile observed in this patient population were similar to that observed in adults.

8.5 Geriatric Use Clinical studies of Allopurinol Sodium for Injection did not include sufficient numbers of patients 65 years and older to determine whether they respond differently than younger patients.

8.6 Renal Impairment Allopurinol and its primary active metabolite, oxypurinol, are eliminated by the kidneys [see Clinical Pharmacology (12.3) ] . Therefore, changes in renal function will likely increase allopurinal and oxypurinol exposure. In patients with decreased renal function, or who have concurrent illnesses that can affect renal function such as hypertension and diabetes mellitus, perform periodic laboratory parameters of renal function, particularly BUN and serum creatinine or creatinine clearance, should be performed. In patients with severely impaired renal function or decreased urate clearance, the half-life of oxypurinol in the plasma is greatly prolonged. Reduce the dose of Allopurinol Sodium for Injection in patients with creatinine clearance ≤ 20 mL/min [see Dosage and Administration (2.2) ] . Patients should be treated with the lowest effective dose, in order to minimize possible side effects.

Allopurinol is a structural analogue of the natural purine base, hypoxanthine. Allopurinol and its oxypurinol metabolite inhibitor xanthine oxidase, the enzyme responsible for the conversion of hypoxanthine to xanthine and of xanthine to uric acid, the end product of purine metabolism in humans. Allopurinol does not disrupt the biosynthesis of purines. The action of oral allopurinol differs from that of uricosuric agents, which lower the serum uric acid level by increasing urinary excretion of uric acid. Allopurinol reduces both the serum and urinary uric acid levels by inhibiting the formation of uric acid. The use of allopurinol to block the formation of urates avoids the hazard of increased renal excretion of uric acid posed by uricosuric drugs.