PIPERACILLIN AND TAZOBACTAM

Piperacillin and tazobactam for injection is an injectable antibacterial combination product consisting of the semisynthetic antibacterial piperacillin sodium and the β-lactamase inhibitor tazobactam sodium for intravenous administration. Piperacillin sodium is derived from D(-)-α-aminobenzyl-penicillin. The chemical name of piperacillin sodium is sodium (2 S ,5 R ,6 R )-6-[( R )-2-(4-ethyl-2,3-dioxo-1-piperazinecarboxamido)-2-phenylacetamido]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate. The chemical formula is C 23 H 26 N 5 NaO 7 S and the molecular weight is 539.5. The chemical structure of piperacillin sodium is: Tazobactam sodium, a derivative of the penicillin nucleus, is a penicillanic acid sulfone. Its chemical name is sodium (2 S, 3 S, 5 R )-3-methyl-7-oxo-3-(1 H -1,2,3-triazol-1-ylmethyl)-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate-4,4-dioxide. The chemical formula is C 10 H 11 N 4 NaO 5 S and the molecular weight is 322.3. The chemical structure of tazobactam sodium is: Piperacillin and tazobactam for injection, piperacillin/tazobactam parenteral combination, is a white to off-white sterile, cryodesiccated powder consisting of piperacillin and tazobactam as their sodium salts packaged in glass bottles. The product does not contain excipients or preservatives. The pharmacy bulk package bottle is a container of sterile preparation which contains many single doses for parenteral use. The contents are intended for use in a pharmacy admixture program and are restricted to the preparation of admixtures for intravenous infusion. Each piperacillin and tazobactam for injection 40.5 g pharmacy bulk package bottle contains piperacillin sodium equivalent to 36 grams of piperacillin and tazobactam sodium equivalent to 4.5 g of tazobactam sufficient for delivery of multiple doses. Piperacillin and tazobactam for injection is a monosodium salt of piperacillin and a monosodium salt of tazobactam containing a total of 2.35 mEq (54 mg) of sodium (Na + ) per gram of piperacillin in the combination product. structure structure 2

Piperacillin and tazobactam for injection is a combination product consisting of a penicillin-class antibacterial, piperacillin, and a β-lactamase inhibitor, tazobactam, indicated for the treatment of patients with moderate to severe infections caused by susceptible isolates of the designated bacteria in the conditions listed below. Piperacillin and Tazobactam for Injection is a combination penicillin-class antibacterial and β-lactamase inhibitor indicated for treatment of: Intra-abdominal infections ( 1.1 ) Skin and skin structure infections ( 1.2 ) Female pelvic infections ( 1.3 ) Community-acquired pneumonia ( 1.4 ) Nosocomial pneumonia ( 1.5 ) 1.1 Intra-abdominal Infections Appendicitis (complicated by rupture or abscess) and peritonitis caused by β-lactamase producing isolates of Escherichia coli or the following members of the Bacteroides fragilis group: B. fragilis , B. ovatus , B. thetaiotaomicron , or B. vulgatus . The individual members of this group were studied in fewer than 10 cases. 1.2 Skin and Skin Structure Infections Uncomplicated and complicated skin and skin structure infections, including cellulitis, cutaneous abscesses and ischemic/diabetic foot infections caused by β-lactamase producing isolates of Staphylococcus aureus . 1.3 Female Pelvic Infections Postpartum endometritis or pelvic inflammatory disease caused by β-lactamase producing isolates of Escherichia coli . 1.4 Community-acquired Pneumonia Community-acquired pneumonia (moderate severity only) caused by β-lactamase producing isolates of Haemophilus influenzae . 1.5 Nosocomial Pneumonia Nosocomial pneumonia (moderate to severe) caused by β-lactamase producing isolates of Staphylococcus aureus and by piperacillin/tazobactam-susceptible Acinetobacter baumannii , Haemophilus influenzae , Klebsiella pneumoniae , and Pseudomonas aeruginosa (Nosocomial pneumonia caused by P. aeruginosa should be treated in combination with an aminoglycoside) [ see Dosage and Administration ( 2 ) ]. To reduce the development of drug-resistant bacteria and maintain the effectiveness of piperacillin and tazobactam for injection and other antibacterial drugs, piperacillin and tazobactam for injection should be used only to treat infections that are proven or strongly suspected to be caused by bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

Piperacillin and tazobactam for injection should be administered by intravenous infusion over 30 minutes. The usual daily dose of Piperacillin and Tazobactam for Injection for adults is 3.375 g every six hours totaling 13.5 g (12.0 g piperacillin/1.5 g tazobactam) ( 2.1 ) Initial presumptive treatment of patients with nosocomial pneumonia should start with Piperacillin and Tazobactam for Injection at a dosage of 4.5 g every six hours plus an aminoglycoside, totaling 18.0 g (16.0 g piperacillin/2.0 g tazobactam). ( 2.2 ) Dosage in patients with renal impairment (≤40 mL/min of CRCL) and dialysis patients should be reduced, based on the degree of actual renal function impairment. ( 2.3 ) For children with appendicitis and/or peritonitis the recommended Piperacillin and Tazobactam for Injection dosage is 100 mg piperacillin/12.5 mg tazobactam per kilogram of body weight, every 8 hours in pediatric patients 9 months of age and older. For pediatric patients 2 to 9 months of age, the recommended dosage is 80 mg piperacillin/10 mg tazobactam per kilogram of body weight, every 8 hours. ( 2.4 ) Piperacillin and Tazobactam for Injection and aminoglycosides should be reconstituted, diluted, and administered separately. Co-administration via Y-site can be done under certain conditions. ( 2.6 ) 2.1 Adult Patients The usual total daily dose of piperacillin and tazobactam for injection for adults is 3.375 g every six hours totaling 13.5 g (12.0 g piperacillin/1.5 g tazobactam). The usual duration of piperacillin and tazobactam for injection treatment is from 7 to 10 days. Piperacillin and tazobactam for injection should be administered by intravenous infusion over 30 minutes. 2.2 Nosocomial Pneumonia Initial presumptive treatment of patients with nosocomial pneumonia should start with piperacillin and tazobactam for injection at a dosage of 4.5 g every six hours plus an aminoglycoside, totaling 18.0 g (16.0 g piperacillin/2.0 g tazobactam). The recommended duration of piperacillin and tazobactam for injection treatment for nosocomial pneumonia is 7 to 14 days. Treatment with the aminoglycoside should be continued in patients from whom P. aeruginosa is isolated. 2.3 Renal Impairment In patients with renal impairment (creatinine clearance ≤ 40 mL/min) and dialysis patients (hemodialysis and CAPD), the intravenous dose of piperacillin and tazobactam for injection should be reduced to the degree of actual renal function impairment. The recommended daily doses of piperacillin and tazobactam for injection for patients with renal impairment are as follows: Table 1: Recommended Dosing of Piperacillin and Tazobactam for Injection in Patients with Normal Renal Function and Renal Impairment (As total grams piperacillin/tazobactam) Renal Function (creatinine clearance, All Indications Nosocomial mL/min) (except nosocomial pneumonia) Pneumonia >40 mL/min 3.375 q6h 4.5 q6h 20-40 mL/min* 2.25 q6h 3.375 q6h <20 mL/min* 2.25 q8h 2.25 q6h Hemodialysis** 2.25 q12h 2.25 q8h CAPD 2.25 q12h 2.25 q8h *Creatinine clearance for patients not receiving hemodialysis **0.75 g (0.67 g piperacillin/0.08 g tazobactam) should be administered following each hemodialysis session on hemodialysis days For patients on hemodialysis, the maximum dose is 2.25 g every twelve hours for all indications other than nosocomial pneumonia and 2.25 g every eight hours for nosocomial pneumonia. Since hemodialysis removes 30% to 40% of the administered dose, an additional dose of 0.75 g piperacillin and tazobactam for injection (0.67 g piperacillin/0.08 g tazobactam) should be administered following each dialysis period on hemodialysis days. No additional dosage of piperacillin and tazobactam for injection is necessary for CAPD patients. 2.4 Pediatric Patients For children with appendicitis and/or peritonitis 9 months of age or older, weighing up to 40 kg, and with normal renal function, the recommended piperacillin and tazobactam for injection dosage is 100 mg piperacillin/12.5 mg tazobactam per kilogram of body weight, every 8 hours. For pediatric patients between 2 months and 9 months of age, the recommended piperacillin and tazobactam for injection dosage based on pharmacokinetic modeling, is 80 mg piperacillin/10 mg tazobactam per kilogram of body weight, every 8 hours [ see Use in Specific Populations ( 8.4 ) and Clinical Pharmacology ( 12.3 ) ]. Pediatric patients weighing over 40 kg and with normal renal function should receive the adult dose. It has not been determined how to adjust piperacillin and tazobactam for injection dosage in pediatric patients with renal impairment. 2.5 Reconstitution and Dilution of Powder Formulations Pharmacy Bulk Package Bottles Reconstituted stock solution must be transferred and further diluted for intravenous infusion. The pharmacy bulk package bottle is for use in a hospital pharmacy admixture service only under a laminar flow hood. After reconstitution, entry into the vial must be made with a sterile transfer set or other sterile dispensing device, and contents should be dispensed as aliquots into intravenous solution using aseptic technique. Use entire contents of pharmacy bulk package bottle promptly. Discard unused portion after 24 hours if stored at room temperature 20°C to 25°C (68°F to 77°F), or after 48 hours if stored at refrigerated temperature 2°C to 8°C (36°F to 46°F). Reconstitute the pharmacy bulk package bottle with exactly 152 mL of a compatible reconstitution diluent, listed below, to a concentration of 200 mg/mL of piperacillin and 25 mg/mL of tazobactam. Shake well until dissolved. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to and during administration whenever solution and container permit. Compatible Reconstitution Diluents for Pharmacy Bulk Bottles 0.9% Sodium chloride for injection Sterile water for injection ‡ Dextrose 5% Bacteriostatic saline/parabens Bacteriostatic water/parabens Bacteriostatic saline/benzyl alcohol Bacteriostatic water/benzyl alcohol Reconstituted piperacillin and tazobactam for injection solution should be further diluted (recommended volume per dose of 50 mL to 150 mL) in a compatible intravenous solution listed below. Administer by infusion over a period of at least 30 minutes. During the infusion it is desirable to discontinue the primary infusion solution. Compatible Intravenous Solutions for Pharmacy Bulk Package Bottles and Single Dose Vials 0.9% Sodium chloride for injection Sterile water for injection ‡ Dextran 6% in saline Dextrose 5% LACTATED RINGER’S SOLUTION IS NOT COMPATIBILE WITH PIPERACILLIN AND TAZOBACTAM FOR INJECTION . ‡ Maximum recommended volume per dose of sterile water for injection is 50 mL. Piperacillin and tazobactam for injection should not be mixed with other drugs in a syringe or infusion bottle since compatibility has not been established. Piperacillin and tazobactam for injection is not chemically stable in solutions that contain only sodium bicarbonate and solutions that significantly alter the pH. Piperacillin and tazobactam for injection should not be added to blood products or albumin hydrolysates. Parenteral drug products should be inspected visually for particulate matter or discoloration prior to administration, whenever solution and container permit. Stability of Piperacillin and Tazobactam for Injection Powder Formulations Following Reconstitution Piperacillin and tazobactam for injection reconstituted from pharmacy bulk package bottles is stable in glass and plastic containers (plastic syringes, I.V. bags and tubing) when used with compatible diluents. The pharmacy bulk package bottle should NOT be frozen after reconstitution. Discard unused portions after storage for 24 hours at room temperature or after storage for 48 hours at refrigerated temperature 2°C to 8°C (36°F to 46°F). Pharmacy bulk package bottles should be used immediately after reconstitution. Discard any unused portion after 24 hours if stored at room temperature 20°C to 25°C (68°F to 77°F), or after 48 hours if stored at refrigerated temperature 2°C to 8°C (36°F to 46°F). Pharmacy bulk package bottles should not be frozen after reconstitution. Stability studies in the I.V. bags have demonstrated chemical stability (potency, pH of reconstituted solution and clarity of solution) for up to 24 hours at room temperature and up to one week at refrigerated temperature. Piperacillin and tazobactam for injection contains no preservatives. Appropriate consideration of aseptic technique should be used. Piperacillin and tazobactam for injection reconstituted from bulk package bottles can be used in ambulatory intravenous infusion pumps. Stability of piperacillin and tazobactam for injection in an ambulatory intravenous infusion pump has been demonstrated for a period of 12 hours at room temperature. Each dose was reconstituted and diluted to a volume of 37.5 mL or 25 mL. One-day supplies of dosing solution were aseptically transferred into the medication reservoir (I.V. bags or cartridge). The reservoir was fitted to a preprogrammed ambulatory intravenous infusion pump per the manufacturer's instructions. Stability of piperacillin and tazobactam for injection is not affected when administered using an ambulatory intravenous infusion pump. 2.6 Compatibility with Aminoglycosides Due to the in vitro inactivation of aminoglycosides by piperacillin, piperacillin and tazobactam for injection and aminoglycosides are recommended for separate administration. Piperacillin and tazobactam for injection and aminoglycosides should be reconstituted, diluted, and administered separately when concomitant therapy with aminoglycosides is indicated [ see Drug Interactions ( 7.1 ) ]. In circumstances where co-administration via Y-site is necessary, piperacillin and tazobactam is compatible for simultaneous coadministration via Y-site infusion only with the following aminoglycosides under the following conditions: Table 2: Compatibility with Aminoglycosides Aminoglycoside Piperacillin and Tazobactam Dose (grams) Piperacillin and Tazobactam Diluent Volume (mL) Aminoglycoside Concentration Range a (mg/mL) Acceptable Diluents Amikacin 2.25, 3.375, 4.5 50, 100, 150 1.75 – 7.5 0.9% sodium chloride or 5% dextrose Gentamicin 2.25, 3.375, 4.5 50, 100 150 0.7 – 3.32 0.9% sodium chloride or 5% dextrose a The concentration ranges in Table 2 are based on administration of the aminoglycoside in divided doses (10-15 mg/kg/day in two daily doses for amikacin and 3-5 mg/kg/day in three daily doses for gentamicin). Administration of amikacin or gentamicin in a single daily dose or in doses exceeding those stated above via Y-site with piperacillin and tazobactam has not been evaluated. See package insert for each aminoglycoside for complete Dosage and Administration instructions. Only the concentration and diluents for amikacin or gentamicin with the dosages of piperacillin and tazobactam for injection listed above have been established as compatible for coadministration via Y-site infusion. Simultaneous coadministration via Y-site infusion in any manner other than listed above may result in inactivation of the aminoglycoside by piperacillin and tazobactam. Piperacillin and tazobactam for injection is not compatible with tobramycin for simultaneous coadministration via Y-site infusion. Compatibility of piperacillin and tazobactam with other aminoglycosides has not been established. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Piperacillin and tazobactam for injection is contraindicated in patients with a history of allergic reactions to any of the penicillins, cephalosporins, or β-lactamase inhibitors. Patients with a history of allergic reactions to any of the penicillins, cephalosporins, or β-lactamase inhibitors. ( 4 )

The most common adverse reactions (incidence >5%) are diarrhea, constipation, nausea, headache and insomnia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Fresenius Kabi USA, LLC Vigilance and Medical Affairs at 1-800-551-7176 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. During the initial clinical investigations, 2621 patients worldwide were treated with piperacillin and tazobactam for injection in phase 3 trials. In the key North American monotherapy clinical trials (n=830 patients), 90% of the adverse events reported were mild to moderate in severity and transient in nature. However, in 3.2% of the patients treated worldwide, piperacillin and tazobactam for injection was discontinued because of adverse events primarily involving the skin (1.3%), including rash and pruritus; the gastrointestinal system (0.9%), including diarrhea, nausea, and vomiting; and allergic reactions (0.5%). Table 3: Adverse Reactions from Piperacillin and Tazobactam for Injection Monotherapy Clinical Trials System Organ Class Adverse Reaction Gastrointestinal disorders Diarrhea (11.3%) Constipation (7.7%) Nausea (6.9%) Vomiting (3.3%) Dyspepsia (3.3%) Abdominal pain (1.3%) Pseudomembranous colitis (≤1%) General disorders and administration site conditions Fever (2.4%) Injection site reaction (≤1%) Rigors (≤1%) Immune system disorders Anaphylaxis (≤1%) Infections and infestations Candidiasis (1.6%) Metabolism and nutrition disorders Hypoglycemia (≤1%) Musculoskeletal and connective tissue disorders Myalgia(≤1%) Arthralgia (≤1%) Nervous system disorders Headache (7.7%) Insomnia (6.6%) Skin and subcutaneous tissue disorders Rash (4.2%, including maculopapular, bullous, and urticarial) Pruritus (3.1%) Vascular disorders Phlebitis (1.3%) Thrombophlebitis (≤1%) Hypotension (≤1%) Purpura (≤1%) Epistaxis (≤1%) Flushing (≤1%) Nosocomial Pneumonia Trials Two trials of nosocomial lower respiratory tract infections were conducted. In one study, 222 patients were treated with piperacillin and tazobactam for injection in a dosing regimen of 4.5 g every 6 hours in combination with an aminoglycoside and 215 patients were treated with imipenem/cilastatin (500 mg/500 mg q6h) in combination with an aminoglycoside. In this trial, treatment-emergent adverse events were reported by 402 patients, 204 (91.9%) in the piperacillin/tazobactam group and 198 (92.1%) in the imipenem/cilastatin group. Twenty-five (11.0%) patients in the piperacillin/tazobactam group and 14 (6.5%) in the imipenem/cilastatin group (p > 0.05) discontinued treatment due to an adverse event. The second trial used a dosing regimen of 3.375 g given every 4 hours with an aminoglycoside. Table 4: Adverse Reactions from Piperacillin and Tazobactam for Injection Plus Aminoglycoside Clinical Trials a System Organ Class Adverse Reaction Blood and lymphatic system disorders Thrombocythemia (1.4%) Anemia (≤1%) Thrombocytopenia (≤1%) Eosinophilia (≤1%) Gastrointestinal disorders Diarrhea (20%) Constipation (8.4%) Nausea (5.8%) Vomiting (2.7%) Dyspepsia (1.9%) Abdominal pain (1.8%) Stomatitis (≤1%) General disorders and administration site conditions Fever (3.2%) Injection site reaction (≤1%) Infections and infestations Oral candidiasis (3.9%) Candidiasis (1.8%) Investigations BUN increased (1.8%) Blood creatinine increased (1.8%) Liver function test abnormal (1.4%) Alkaline phosphatase increased (≤1%) Aspartate aminotransferase increased (≤1%) Alanine aminotransferase increased (≤1%) Metabolism and nutrition disorders Hypoglycemia (≤1%) Hypokalemia (≤1%) Nervous system disorders Headache (4.5%) Insomnia (4.5%) Renal and urinary disorders Renal failure (≤1%) Skin and subcutaneous tissue disorders Rash (3.9%) Pruritus (3.2%) Vascular disorders Thrombophlebitis (1.3%) Hypotension (1.3%) a For adverse drug reactions that appeared in both studies the higher frequency is presented. Pediatrics Studies of piperacillin and tazobactam for injection in pediatric patients suggest a similar safety profile to that seen in adults. In a prospective, randomized, comparative, open-label clinical trial of pediatric patients with severe intra-abdominal infections (including appendicitis and/or peritonitis), 273 patients were treated with piperacillin and tazobactam for injection (112.5 mg/kg every 8 hours) and 269 patients were treated with cefotaxime (50 mg/kg) plus metronidazole (7.5 mg/kg) every 8 hours. In this trial, treatment-emergent adverse events were reported by 146 patients, 73 (26.7%) in the piperacillin and tazobactam for injection group and 73 (27.1%) in the cefotaxime/metronidazole group. Six patients (2.2%) in the piperacillin and tazobactam for injection group and 5 patients (1.9%) in the cefotaxime/metronidazole group discontinued due to an adverse event. Adverse Laboratory Events (Seen During Clinical Trials) Of the trials reported, including that of nosocomial lower respiratory tract infections in which a higher dose of piperacillin and tazobactam for injection was used in combination with an aminoglycoside, changes in laboratory parameters include: Hematologic —decreases in hemoglobin and hematocrit, thrombocytopenia, increases in platelet count, eosinophilia, leukopenia, neutropenia. These patients were withdrawn from therapy; some had accompanying systemic symptoms (e.g., fever, rigors, chills). Coagulation —positive direct Coombs' test, prolonged prothrombin time, prolonged partial thromboplastin time Hepatic —transient elevations of AST (SGOT), ALT (SGPT), alkaline phosphatase, bilirubin Renal —increases in serum creatinine, blood urea nitrogen Additional laboratory events include abnormalities in electrolytes (i.e., increases and decreases in sodium, potassium, and calcium), hyperglycemia, decreases in total protein or albumin, blood glucose decreased, gamma-glutamyltransferase increased, hypokalemia, and bleeding time prolonged. 6.2 Post-Marketing Experience In addition to the adverse drug reactions identified in clinical trials in Table 3 and Table 4, the following adverse reactions have been identified during postapproval use of piperacillin and tazobactam for injection. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish causal relationship to drug exposure. Gastrointestinal —hepatitis, jaundice Hematologic —hemolytic anemia, agranulocytosis, pancytopenia Immune —hypersensitivity reactions, anaphylactic/anaphylactoid reactions (including shock) Renal —interstitial nephritis Skin and Appendages —erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis 6.3 Additional Experience with piperacillin The following adverse reaction has also been reported for piperacillin for injection: Skeletal —prolonged muscle relaxation [ see Drug Interactions ( 7.4 )]. Post-marketing experience with piperacillin and tazobactam for injection in pediatric patients suggests a similar safety profile to that seen in adults.

Piperacillin and Tazobactam for Injection administration can significantly reduce tobramycin concentrations in hemodialysis patients. Monitor tobramycin concentrations in these patients. ( 7.1 ) Probenecid prolongs the half-lives of piperacillin and tazobactam and should not be co-administered with Piperacillin and Tazobactam for Injection unless the benefit outweighs the risk. ( 7.2 ) Monitor coagulation parameters in patients receiving Piperacillin and Tazobactam for Injection and heparin or oral anticoagulants. ( 7.3 ) Piperacillin and Tazobactam for Injection may prolong the neuromuscular blockade of vecuronium and other non-depolarizing muscle relaxants. Monitor for adverse reactions related to neuromuscular blockade. ( 7.4 ) 7.1 Aminoglycosides Piperacillin may inactivate aminoglycosides by converting them to microbiologically inert amides. In vivo inactivation : When aminoglycosides are administered in conjunction with piperacillin to patients with end-stage renal disease requiring hemodialysis, the concentrations of the aminoglycosides (especially tobramycin) may be significantly reduced and should be monitored. Sequential administration of piperacillin and tazobactam for injection and tobramycin to patients with either normal renal function or mild to moderate renal impairment has been shown to modestly decrease serum concentrations of tobramycin but no dosage adjustment is considered necessary. In vitro inactivation: Due to the in vitro inactivation of aminoglycosides by piperacillin, piperacillin and tazobactam for injection and aminoglycosides are recommended for separate administration. Piperacillin and tazobactam for injection and aminoglycosides should be reconstituted, diluted, and administered separately when concomitant therapy with aminoglycosides is indicated. Piperacillin and tazobactam for injection is compatible with amikacin and gentamicin for simultaneous Y-site infusion in certain diluents and at specific concentrations. Piperacillin and tazobactam for injection is not compatible with tobramycin for simultaneous Y-site infusion [ see Dosage and Administration ( 2.6 ) ]. 7.2 Probenecid Probenecid administered concomitantly with piperacillin and tazobactam prolongs the half-life of piperacillin by 21% and that of tazobactam by 71% because probenecid inhibits tubular renal secretion of both piperacillin and tazobactam. Probenecid should not be co-administered with piperacillin and tazobactam for injection unless the benefit outweighs the risk. 7.3 Anticoagulants Coagulation parameters should be tested more frequently and monitored regularly during simultaneous administration of high doses of heparin, oral anticoagulants, or other drugs that may affect the blood coagulation system or the thrombocyte function. [ see Warnings and Precautions ( 5.4 ) ] 7.4 Vecuronium Piperacillin when used concomitantly with vecuronium has been implicated in the prolongation of the neuromuscular blockade of vecuronium. Piperacillin and tazobactam for injection could produce the same phenomenon if given along with vecuronium. Due to their similar mechanism of action, it is expected that the neuromuscular blockade produced by any of the non-depolarizing muscle relaxants could be prolonged in the presence of piperacillin. Monitor for adverse reactions related to neuromuscular blockade (See package insert for vecuronium bromide). 7.5 Methotrexate Limited data suggests that co-administration of methotrexate and piperacillin may reduce the clearance of methotrexate due to competition for renal secretion. The impact of tazobactam on the elimination of methotrexate has not been evaluated. If concurrent therapy is necessary, serum concentrations of methotrexate as well as the signs and symptoms of methotrexate toxicity should be frequently monitored. 7.6 Effects on Laboratory Tests There have been reports of positive test results using the Bio-Rad Laboratories Platelia Aspergillus EIA test in patients receiving piperacillin/tazobactam injection who were subsequently found to be free of Aspergillus infection. Cross-reactions with non- Aspergillus polysaccharides and polyfuranoses with the Bio-Rad Laboratories Platelia Aspergillus EIA test have been reported. Therefore, positive test results in patients receiving piperacillin/tazobactam should be interpreted cautiously and confirmed by other diagnostic methods. As with other penicillins, the administration of piperacillin and tazobactam for injection may result in a false-positive reaction for glucose in the urine using a copper-reduction method (CLINITEST ® ). It is recommended that glucose tests based on enzymatic glucose oxidase reactions be used.