PIPERACILLIN-TAZOBACTAM

General Administration Information
For storage information, see the specific product information within the How Supplied section.

Route-Specific Administration

Injectable Administration
-Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.
-Piperacillin; tazobactam 2.25 g corresponds to 2 g piperacillin and 0.25 g tazobactam.
-Piperacillin; tazobactam 3.375 g corresponds to 3 g piperacillin and 0.375 g tazobactam.
-Piperacillin; tazobactam 4.5 g corresponds to 4 g piperacillin and 0.5 g tazobactam.
Intravenous Administration
Powder Vials for Injection
Reconstitution
-Reconstitute with the appropriate volume of a compatible IV solution to a concentration of 202.5 mg/mL (180 mg/mL piperacillin and 22.5 mg/mL tazobactam):-Reconstitute the 2.25 g (2 g piperacillin and 0.25 g tazobactam) vial with 10 mL of a compatible IV solution.
-Reconstitute the 3.375 g (3 g piperacillin and 0.375 g tazobactam) vial with 15 mL of a compatible IV solution.
-Reconstitute the 4.5 g (4 g piperacillin and 0.5 g tazobactam) vial with 20 mL of a compatible IV solution.

-Compatible IV solutions include 0.9% Sodium Chloride Injection, Sterile Water for Injection, 5% Dextrose Injection, Bacteriostatic Water/Parabens for Injection, Bacteriostatic Saline/Benzyl Alcohol for Injection, and Bacteriostatic Water/Benzyl Alcohol for Injection.
-Swirl vial until the powder is fully dissolved.
-Further dilution is necessary.
-Storage: Reconstituted vials should be used immediately. Discard any unused portion after 24 hours if stored at room temperature (20 to 25 degrees C or 68 to 77 degrees F) or after 48 hours if refrigerated (2 to 8 degrees C or 36 to 46 degrees F).

Dilution
-For patients weighing more than 40 kg, reconstituted vials should be further diluted in 50 to 150 mL of a compatible IV solution.
-For patients weighing 40 kg or less, calculate the required volume (mL) of reconstituted solution based on the required dose. Aseptically withdraw the required volume of the reconstituted solution and further dilute to a final piperacillin concentration of 20 to 80 mg/mL (tazobactam concentration of 2.5 to 10 mg/mL) in a compatible IV solution in an appropriately sized syringe or IV bag.
-Compatible IV solutions include 0.9% Sodium Chloride Injection, Dextran 6% in Saline Injection, and 5% Dextrose Injection.
-Lactated Ringer's Injection is ONLY compatible with piperacillin; tazobactam containing edetate disodium dihydrate (EDTA).
-If Sterile Water for Injection is used as the diluent, do not exceed a maximum final volume of 50 mL.
-Storage: Diluted solutions in IV glass or plastic containers are stable for up to 24 hours at room temperature and up to one week under refrigeration.

Bulk Vials for Injection
Reconstitution
-Reconstitute pharmacy bulk vials with 152 mL of a compatible IV solution to a concentration of 225 mg/mL (200 mg/mL piperacillin and 25 mg/mL tazobactam).
-Compatible IV solutions include 0.9% Sodium Chloride Injection, Sterile Water for Injection, 5% Dextrose Injection, Bacteriostatic Water/Parabens for Injection, Bacteriostatic Saline/Benzyl Alcohol for Injection, and Bacteriostatic Water/Benzyl Alcohol for Injection.
-Swirl vial until the powder is fully dissolved.
-After reconstitution, entry into the vial must be made with a sterile dispensing device. Use the entire contents of the vial promptly.
-Further dilution is necessary
-Storage: Reconstituted vials should be used immediately. Discard any unused portion after 24 hours if stored at room temperature (20 to 25 degrees C or 68 to 77 degrees F) or after 48 hours if refrigerated (2 to 8 degrees C or 36 to 46 degrees F). Do not freeze reconstituted vials.

Dilution
-For patients weighing more than 40 kg, reconstituted vials should be further diluted in 50 to 150 mL of a compatible IV solution.
-For patients weighing 40 kg or less, calculate the required volume (mL) of reconstituted solution based on the required dose. Aseptically withdraw the required volume of the reconstituted solution and further dilute to a final piperacillin concentration of 20 to 80 mg/mL (tazobactam concentration of 2.5 to 10 mg/mL) in a compatible IV solution in an appropriately sized syringe or IV bag.
-Compatible IV solutions include 0.9% Sodium Chloride Injection, Dextran 6% in Saline Injection, and 5% Dextrose Injection.
-Lactated Ringer's Injection is ONLY compatible with piperacillin; tazobactam containing edetate disodium dihydrate (EDTA).
-If Sterile Water for Injection is used as the diluent, do not exceed a maximum final volume of 50 mL.
-Storage: Diluted solutions in IV glass or plastic containers are stable for up to 24 hours at room temperature and up to one week under refrigeration.

Frozen Pre-mixed Bags
-Use is not recommended for doses other than 2.25 g (2 g piperacillin and 0.25 g tazobactam), 3.375 g (3 g piperacillin and 0.375 g tazobactam), or 4.5 g (4 g piperacillin and 0.5 g tazobactam); consider alternative formulations.
-Handle frozen product containers with care as they may be fragile in the frozen state.
-Thaw frozen containers at room temperature (20 to 25 degrees C or 68 to 77 degrees F) or under refrigeration (2 to 8 degrees C or 36 to 46 degrees F).
-Do not force thaw by immersion in water baths or by microwave irradiation.
-Check for leaks by squeezing the bag firmly.
-Do not add supplementary medication.
-Contents of the solution may precipitate in the frozen state and should dissolve with little or no agitation once the solution has reached room temperature.
-Storage: The thawed solution is stable for 24 hours at room temperature (20 to 25 degrees C or 68 to 77 degrees F) or for 14 days under refrigeration (2 to 8 degrees C or 36 to 46 degrees F). Do not refreeze thawed product.

Intermittent IV Infusion
-Infuse IV over at least 30 minutes.
-Do not use plastic containers in series connections as this could result in an embolism due to residual air being drawn from the primary container before administration of the fluid from the secondary container is complete.

Ambulatory IV Infusion
-Piperacillin; tazobactam reconstituted and diluted from single-use and bulk vials can be used in ambulatory intravenous infusion pumps.
-Doses diluted to a final volume of 37.5 mL or 25 mL have been shown to be stable for 12 hours at room temperature in medication reservoirs that were fitted into preprogrammed ambulatory IV infusion pumps.

Piperacillin; tazobactam studies and post-marketing data in pediatric patients have shown a similar safety profile to that seen in adults.

Gastrointestinal adverse events, including diarrhea (7%), constipation (1.1%), vomiting (3.7%), abdominal pain (1.8%), and bloody diarrhea (1.1%) were reported in pediatric patients during piperacillin; tazobactam clinical trials. Nausea (5-10%), dyspepsia (1-5%), stomatitis (<= 1%), and colitis (<= 1%) were also noted in adults during clinical trials.

Hypotension was reported in <= 1% of adult patients in piperacillin; tazobactam clinical trials.

Fever was reported in 4.8% of pediatric patients in piperacillin; tazobactam clinical trials. Patients with cystic fibrosis tend to experience fever and rash more frequently than other populations. Flushing and rigors were reported in <= 1% of adult patients in clinical trials. Chills have also been reported during therapy.

Hypersensitivity and skin and soft tissue reactions are among the most frequent adverse reactions to the penicillins, including piperacillin; tazobactam. A local injection site reaction was reported in 3.3% of pediatric patients in clinical trials. Hypersensitivity reactions, anaphylactoid reactions (including anaphylactic shock), erythema multiforme, Stevens-Johnson syndrome, acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS), exfoliative dermatitis, and toxic epidermal necrolysis have been noted in postmarketing reports. Closely monitor patients who develop a rash and discontinue piperacillin; tazobactam if lesions progress. Rash, maculopapular rash, bullous rash, and urticaria have been reported in approximately 3% to 5% of adults during clinical trials. An increased incidence of rash has been noted with piperacillin therapy in patients with cystic fibrosis. Other adverse events reported in adult clinical trials include pruritus (3% to 5%), phlebitis, and thrombophlebitis (less than 2%). Angioedema has also been reported with the penicillins.

As with other penicillins, piperacillin; tazobactam may cause neuromuscular excitability or seizures. Patients receiving higher doses, especially patients with renal impairment, may be at greater risk for central nervous system adverse reactions. Closely monitor patients with renal impairment or seizure disorders for signs and symptoms of neuromuscular excitability or seizures. Additionally, headache (4.5% to 7.7%) and insomnia (4.5% to 6.6%) have been reported during piperacillin; tazobactam clinical trials. Delirium has been noted in postmarketing reports.

Each gram of piperacillin; tazobactam contains 65 mg (2.84 mEq) of sodium; patients who are sensitive to sodium intake or those receiving high doses may develop hypernatremia. Other electrolyte abnormalities that have been reported with piperacillin; tazobactam include hypokalemia (reported in <= 1% of adults) and increases or decreases in sodium, potassium, and calcium. Monitor serum electrolytes periodically as clinically appropriate; patients with additional risk factors for electrolyte disturbances should be monitored more closely.

Renal failure (unspecified) occurred in <= 1% of patients during piperacillin; tazobactam clinical trials in adults. Increased BUN and serum creatinine occurred in approximately 2% of adult patients. Interstitial nephritis has been noted in post-marketing reports.

Hypoglycemia was reported in <= 1% of adult patients during piperacillin; tazobactam clinical trials. Hyperglycemia was also observed. The incidence of alterations in blood glucose in pediatric patients has not been clearly defined; however, the overall safety profile of piperacillin; tazobactam in children has been reported to be similar to that of adults. Monitor serum glucose in patients with tenuous glucose control (e.g., neonates, diabetic patients) until the drug's effect on the patient's blood glucose is known.

Elevated hepatic enzymes (AST/SGOT) was reported in 1.1% of pediatric patients during clinical trials of piperacillin; tazobactam. Abnormal liver function tests (< 2%), increased alkaline phosphatase (<= 1%), and hyperbilirubinemia have also been observed in adult clinical trials. Hepatitis and jaundice have been noted in post-marketing reports with piperacillin; tazobactam. Because of the potential for increased bilirubin, monitor neonates' bilirubin status carefully. Other related laboratory findings include increased gamma-glutamyltransferase (GGT) and decreases in total protein or albumin.

The use of beta-lactams, including piperacillin; tazobactam, is associated with various drug-induced hematological disorders in a small percentage of patients; all cell lines have the potential to be affected. Abnormalities in coagulation tests such as clotting time, platelet aggregation, and prothrombin time can occur and appear to be more common in patients with renal failure. Platelet dysfunction occurs to varying degrees with the extended-spectrum penicillins. Piperacillin can bind to platelets to prevent aggregation, which causes prolonged bleeding time. Hematologic adverse events reported in <= 1% of adult patients in clinical trials include anemia, eosinophilia, epistaxis, purpura, thrombocytopenia, and thrombocythemia (thrombocytosis; < 2%). Other adverse events reported in adults include decreases in hemoglobin and hematocrit, leukopenia, neutropenia, positive direct Coombs' test, prolonged prothrombin time, and prolonged partial thromboplastin time. Leukopenia and neutropenia appear to be reversible and most frequently associated with prolonged administration. Hematologic parameters should be periodically monitored during therapy, particularly with prolonged therapy (i.e., >= 21 days). Post-marketing reports have included cases of hemolytic anemia, agranulocytosis, and pancytopenia.

Microbial overgrowth and superinfection can occur with antibiotic use. C. difficile-associated diarrhea (CDAD) or pseudomembranous colitis (up to 1% of adults) has been reported with piperacillin; tazobactam. If pseudomembranous colitis is suspected or confirmed, ongoing antibacterial therapy not directed against C. difficile may need to be discontinued. Institute appropriate fluid and electrolyte management, protein supplementation, C. difficile-directed antibacterial therapy, and surgical evaluation as clinically appropriate. In addition, candidiasis was noted in 1.6% of patients receiving the drug as monotherapy and in 1.8% to 3.9% of patients treated with piperacillin; tazobactam/aminoglycoside combination therapy.

Musculoskeletal adverse events reported in 1% or less of adults in piperacillin; tazobactam clinical trials include myalgia and arthralgia. Prolonged neuromuscular blockade has been reported during postmarketing use.

Eosinophilic pneumonia has been noted in post-marketing reports with piperacillin; tazobactam.

Hemophagocytic lymphohistiocytosis (HLH) has been reported in pediatric and adult patients treated with piperacillin; tazobactam. Signs and symptoms of HLH may include fever, rash, lymphadenopathy, hepatosplenomegaly, and cytopenia. If HLH is suspected, discontinue piperacillin; tazobactam immediately and institute appropriate management.

Dosage adjustments may be required in patients with renal impairment or in those who are receiving dialysis. Patients receiving higher doses, especially patients with renal impairment, may be at greater risk for central nervous system adverse reactions. Closely monitor patients with renal impairment for signs and symptoms of neuromuscular excitability or convulsions. Hematologic adverse reactions are also more likely to occur in patients with renal failure. Additionally, piperacillin; tazobactam use was found to be an independent risk factor for renal failure (OR 1.7; 95% CI, 1.18 to 2.43) and was associated with delayed recovery of renal function as compared to other beta-lactam antibacterial drugs in a randomized, multicenter, controlled trial in critically ill adult patients. Based on this study, consider alternative treatment options in patients with critical illness. If alternative treatment options are inadequate or unavailable, monitor renal function during treatment with piperacillin; tazobactam.

Piperacillin; tazobactam contains sodium. Consider the sodium content in piperacillin; tazobactam when treating patients requiring sodium restriction. Also, monitor electrolytes periodically in patients with low potassium reserves (i.e., hypokalemia).

Piperacillin; tazobactam is contraindicated in patients with penicillin hypersensitivity, beta-lactamase hypersensitivity, or cephalosporin hypersensitivity. Serious and occasionally fatal hypersensitivity (i.e., anaphylactic/anaphylactoid) reactions, including shock, have been reported in patients receiving piperacillin; tazobactam. These reactions are more likely to occur in individuals with a history of penicillin, cephalosporin, or carbapenem hypersensitivity or a history of sensitivity to multiple allergens. Before initiating therapy with piperacillin; tazobactam, carefully inquire about any previous hypersensitivity reactions. If an allergic reaction occurs, discontinue piperacillin; tazobactam, and initiate appropriate therapy.

Bleeding has occurred in some patients receiving beta-lactam drugs, including piperacillin. These reactions have sometimes been associated with abnormalities of coagulation tests, such as clotting time, platelet aggregation, and prothrombin time, and are more likely to occur in patients with renal failure. If bleeding occurs, discontinue piperacillin; tazobactam, and initiate appropriate therapy. Monitor hematopoietic function periodically, especially with prolonged therapy (i.e., 21 days or more). Monitor coagulation parameters more frequently and regularly during simultaneous administration of anticoagulant therapy or other drugs that may affect the blood coagulation system or the thrombocyte function.

Consider pseudomembranous colitis in patients presenting with diarrhea after antibacterial use. Careful medical history is necessary as pseudomembranous colitis has been reported to occur over 2 months after the administration of antibacterial agents. Almost all antibacterial agents, including piperacillin; tazobactam, have been associated with pseudomembranous colitis or C. difficile-associated diarrhea (CDAD) which may range in severity from mild to life-threatening. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.

As with other penicillins, piperacillin; tazobactam may cause neuromuscular excitability or seizures. Patients receiving higher doses, especially patients with renal impairment, may be at greater risk for central nervous system adverse reactions. Closely monitor patients with a history of seizure disorder for signs and symptoms of neuromuscular excitability or seizures.

Piperacillin; tazobactam may cause laboratory test interference. There have been reports of positive test results using the Bio-Rad Laboratories Platelia Aspergillus EIA test in patients receiving piperacillin; tazobactam 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, interpret positive test results with caution in patients receiving piperacillin; tazobactam and confirm by other diagnostic methods. As with other penicillins, the administration of piperacillin; tazobactam may result in a false-positive reaction for glucose in the urine using a copper-reduction method (i.e., Clinitest). It is recommended that glucose tests based on enzymatic glucose oxidase reactions be used.

As with other semisynthetic penicillins, piperacillin has been associated with an increased incidence of fever and rash in cystic fibrosis patients.

Description: Piperacillin and tazobactam are combined in a single intravenous formulation to provide a broad spectrum of activity. Piperacillin; tazobactam is commonly used to treat serious nosocomial infections that are often polymicrobial in nature. Piperacillin, a ureidopenicillin, is an extended-spectrum penicillin. Tazobactam, an irreversible beta-lactamase inhibitor, prevents beta-lactamase destruction of piperacillin. Tazobactam blocks the activity of susceptible beta-lactamases, thus enhancing the intrinsic activity of piperacillin. Piperacillin; tazobactam is effective in the treatment of moderate to severe nosocomial and polymicrobial infections, including intra-abdominal infections, skin and soft-tissue infections, febrile neutropenia, and lower respiratory tract infections. The combination, however, does not have any more activity against Pseudomonas aeruginosa than does piperacillin alone. Piperacillin; tazobactam is FDA approved for use in pediatric patients as young as 2 months for intra-abdominal infections and nosocomial pneumonia.

Per the manufacturer, this drug has been shown to be active against most strains of the following microorganisms either in vitro and/or in clinical infections: Acinetobacter baumannii, Bacteroides fragilis, Bacteroides ovatus, Bacteroides thetaiotaomicron, Bacteroides vulgatus, Citrobacter koseri, Clostridium perfringens, Enterococcus faecalis, Escherichia coli, Haemophilus influenzae (beta-lactamase negative), Haemophilus influenzae (beta-lactamase positive), Klebsiella pneumoniae, Moraxella catarrhalis, Morganella morganii, Neisseria gonorrhoeae, Parabacteroides distasonis, Prevotella melaninogenica, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Pseudomonas aeruginosa, Salmonella enteritidis, Serratia marcescens, Staphylococcus aureus (MSSA), Staphylococcus epidermidis, Streptococcus agalactiae (group B streptococci), Streptococcus pneumoniae, Streptococcus pyogenes (group A beta-hemolytic streptococci), Viridans streptococci
NOTE: The safety and effectiveness in treating clinical infections due to organisms with in vitro data only have not been established in adequate and well-controlled clinical trials.

This drug may also have activity against the following microorganisms: Bacillus anthracis, Enterobacter sp., Fusobacterium nucleatum, Klebsiella oxytoca, Neisseria meningitidis
NOTE: Some organisms may not have been adequately studied during clinical trials; therefore, exclusion from this list does not necessarily negate the drug's activity against the organism.

For the treatment of community-acquired pneumonia* (CAP), nosocomial pneumonia, and pleural empyema*:
-for the treatment of community-acquired pneumonia (CAP) using conventional dosing*:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours.
Neonates older than 30 weeks postmenstrual age: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours.
Infants 1 to 3 months: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours.
Infants, Children, and Adolescents 4 months to 17 years: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]). Treat for up to 10 days depending on severity of illness and causative organism.
-for the treatment of nosocomial pneumonia using conventional dosing:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger*: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours.
Neonates older than 30 weeks postmenstrual age*: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours.
Infants younger than 2 months*: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours.
Infants 2 to 9 months: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours for 7 to 14 days. For patients with Pseudomonas pneumonia, add an aminoglycoside.
Infants 10 to 11 months: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 6 hours for 7 to 14 days. For patients with Pseudomonas pneumonia, add an aminoglycoside.
Children and Adolescents weighing 40 kg or less: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 6 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) for 7 to 14 days. For patients with Pseudomonas pneumonia, add an aminoglycoside.
Children and Adolescents weighing more than 40 kg: 4.5 g (4 g piperacillin and 0.5 g tazobactam) IV every 6 hours for 7 to 14 days. For patients with Pseudomonas pneumonia, add an aminoglycoside.
-for the treatment of hospital-acquired and postprocedural empyema* using conventional dosing:
Intravenous dosage:
Infants, Children, and Adolescents: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]). Use in combination with vancomycin for at least 2 weeks after drainage and defervescence.
-for the treatment of pneumonia using extended-infusion dosing*:
Intravenous dosage:
Infants, Children, and Adolescents: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) administered over 4 hours IV every 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) based on limited data.

For the treatment of intraabdominal infections, including peritonitis, appendicitis, and intraabdominal abscess:
-for the treatment of complicated community-acquired intraabdominal infections with adequate source control using conventional dosing:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger*: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours for 7 to 10 days.
Neonates older than 30 weeks postmenstrual age*: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours for 7 to 10 days.
Infants younger than 2 months*: 200 to 300 mg/kg/day piperacillin component (225 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.
Infants, Children, and Adolescents 2 months to 17 years: 200 to 300 mg/kg/day piperacillin component (225 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.
-for the treatment of uncomplicated intraabdominal infections using conventional dosing:
Intravenous dosage:
Infants, Children, and Adolescents 2 months to 17 years: 200 to 300 mg/kg/day piperacillin component (225 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]). Antibiotics should be discontinued within 24 hours. Uncomplicated infections include acute appendicitis without perforation, abscess, or local peritonitis; traumatic bowel perforations repaired within 12 hours; acute cholecystitis without perforation; and ischemic, non-perforated bowel.
Infants younger than 2 months*: 200 to 300 mg/kg/day piperacillin component (225 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours. Antibiotics should be discontinued within 24 hours. Uncomplicated infections include acute appendicitis without perforation, abscess, or local peritonitis; traumatic bowel perforations repaired within 12 hours; acute cholecystitis without perforation; and ischemic, non-perforated bowel.
-for intraabdominal infections using extended-infusion dosing*:
Intravenous dosage:
Infants, Children, and Adolescents: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) administered over 4 hours IV every 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) based on limited data.

For the empiric treatment of febrile neutropenia*:
-for febrile neutropenia using conventional dosing:
Intravenous dosage:
Infants, Children, and Adolescents: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours (Max: 4 g/dose piperacillin component [4.5 g/dose piperacillin; tazobactam]). Piperacillin; tazobactam, an antipseudomonal penicillin, has been successfully used for the empiric treatment of febrile neutropenia in pediatric patients as monotherapy or in combination with an aminoglycoside. Guidelines for the management of fever and neutropenia in cancer patients recommend monotherapy with an antipseudomonal beta-lactam or a carbapenem as empiric treatment in high-risk patients; addition of a second gram-negative antimicrobial agent (i.e., aminoglycoside, aztreonam) is recommended for patients who are clinically unstable, when a resistant infection is suspected, or for centers with high rates of resistant pathogens.
-for febrile neutropenia using extended-infusion dosing:
Intravenous dosage:
Infants, Children, and Adolescents: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) administered over 4 hours IV every 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) based on limited data.

For the treatment of acute pulmonary exacerbations in patients with cystic fibrosis*:
-for acute pulmonary exacerbations in patients with cystic fibrosis using conventional dosing:
Intravenous dosage:
Infants, Children, and Adolescents: 80 to 100 mg/kg/dose piperacillin component (90 to 112.5 mg/kg/dose piperacillin; tazobactam) IV every 6 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) is recommended by guidelines. However, a review of the literature suggests that higher doses of 75 to 100 mg/kg/dose piperacillin component (84 to 112.5 mg/kg/dose piperacillin; tazobactam) IV every 4 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) may be warranted based on piperacillin studies and pharmacokinetic/pharmacodynamic modeling. These higher doses may be needed to maintain adequate serum concentrations in the treatment of pseudomonal isolates with higher MICs.
-for acute pulmonary exacerbations in patients with cystic fibrosis using extended-infusion dosing:
Intravenous dosage:
Infants, Children, and Adolescents: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) administered over 4 hours IV every 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) based on limited data.

For surgical infection prophylaxis* in patients undergoing liver transplantation:
Intravenous dosage:
Infants 2 to 9 months: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV once within 60 minutes before surgical incision, and redose during surgery every 2 hours from the initiation of the preoperative dose. The duration of prophylaxis should not exceed 24 hours.
Infants 10 to 11 months, Children, and Adolescents weighing 40 kg or less: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV once within 60 minutes before surgical incision, and redose during surgery every 2 hours from the initiation of the preoperative dose. The duration of prophylaxis should not exceed 24 hours.
Children and Adolescents weighing more than 40 kg: 3.375 g (3 g piperacillin and 0.375 g tazobactam) IV once within 60 minutes before surgical incision, and redose during surgery every 2 hours from the initiation of the preoperative dose. The duration of prophylaxis should not exceed 24 hours.

For the treatment of bacteremia* and sepsis*:
-for the treatment of bacteremia and sepsis using conventional dosing*:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours.
Neonates older than 30 weeks postmenstrual age: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours. Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response. Neonates younger than 37 weeks gestational age were excluded from guideline scope.
Infants, Children, and Adolescents: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]). Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.
-for the treatment of bacteremia and sepsis using extended-infusion dosing*:
Intravenous dosage:
Infants, Children, and Adolescents: Data are very limited. 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) administered over 4 hours IV every 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]). Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.

For the treatment of skin and skin structure infections*, including cellulitis*, erysipelas*, skin abscesses*, necrotizing infections*, and pyomyositis*:
-for the treatment of nonpurulent skin infections*, such as cellulitis* and erysipelas*:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours for 5 to 14 days.
Neonates older than 30 weeks postmenstrual age: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours for 5 to 14 days.
Infants, Children, and Adolescents: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) (Max: 3 g/dose piperacillin [3.375 g/dose piperacillin; tazobactam]) IV divided every 6 to 8 hours for 5 to 14 days.
-for the treatment of purulent skin infections*, such as skin abscesses*:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours for 5 to 10 days plus incision and drainage.
Neonates older than 30 weeks postmenstrual age: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours for 5 to 10 days plus incision and drainage.
Infants, Children, and Adolescents: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) (Max: 3 g/dose piperacillin [3.375 g/dose piperacillin; tazobactam]) IV divided every 6 to 8 hours for 5 to 10 days plus incision and drainage.
-for the treatment of necrotizing infections of the skin, fascia, and muscle*:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours plus vancomycin for mixed necrotizing infections.
Neonates older than 30 weeks postmenstrual age: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours plus vancomycin for mixed necrotizing infections.
Infants, Children, and Adolescents: 60 to 75 mg/kg/dose piperacillin component (67.5 to 84 mg/kg/dose piperacillin; tazobactam) (Max: 3 g/dose piperacillin [3.375 g/dose piperacillin; tazobactam]) IV every 6 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours plus vancomycin for mixed necrotizing infections.
-for the treatment of pyomyositis*:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours for 14 to 21 days plus vancomycin in patients with underlying conditions.
Neonates older than 30 weeks postmenstrual age: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours for 14 to 21 days plus vancomycin in patients with underlying conditions.
Infants, Children, and Adolescents: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) (Max: 3 g/dose piperacillin [3.375 g/dose piperacillin; tazobactam]) IV divided every 6 to 8 hours for 14 to 21 days plus vancomycin in patients with underlying conditions.

For the treatment of infective endocarditis*:
Intravenous dosage:
Neonates 30 weeks postmenstrual age and younger: 100 mg/kg/dose piperacillin component (112.5 mg/kg/dose piperacillin; tazobactam) IV every 8 hours.
Neonates older than 30 weeks postmenstrual age: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 6 hours.
Infants: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 8 hours.
Children and Adolescents: 80 mg/kg/dose piperacillin component (90 mg/kg/dose piperacillin; tazobactam) IV every 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) for at least 6 weeks. Piperacillin; tazobactam, in combination with an aminoglycoside, is recommended as an alternative therapy for endocarditis due to gram-negative microorganisms.

For the treatment of urinary tract infection (UTI)*, including catheter-associated urinary tract infection*:
-for the treatment of UTI*:
Intravenous dosage:
Infants, Children, and Adolescents: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]). Treat for 48 to 72 hours or until patient is clinically stable and afebrile, followed by oral antibiotics for a total duration of 7 to 14 days.
-for the treatment of catheter-associated UTI*:
Intravenous dosage:
Infants, Children, and Adolescents: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) for 7 to 14 days.

For the treatment of bronchiectasis*:
-for the treatment of acute exacerbations of bronchiectasis*:
Intravenous dosage:
Infants, Children, and Adolescents: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) for 14 days.
-for the eradication of first or new isolates of Pseudomonas aeruginosa in patients with bronchiectasis*:
Intravenous dosage:
Infants, Children, and Adolescents: 240 to 300 mg/kg/day piperacillin component (270 to 337.5 mg/kg/day piperacillin; tazobactam) IV divided every 6 to 8 hours (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) for 14 days with or without a systemic aminoglycoside or inhaled antibiotics, followed by inhaled antibiotics for 4 to 12 weeks.

For the treatment of anthrax*:
-for the treatment of systemic anthrax* without aerosol exposure, including those with signs and symptoms of meningitis, as part of combination therapy:
Intravenous dosage:
Infants, Children, and Adolescents: 75 mg/kg/dose piperacillin component (84.4 mg/kg/dose piperacillin; tazobactam) (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) IV every 6 hours for at least 14 days; may consider step-down to oral therapy.
-for the treatment of systemic anthrax* with aerosol exposure, including those with signs and symptoms of meningitis, as part of combination therapy:
Intravenous dosage:
Infants, Children, and Adolescents: 75 mg/kg/dose piperacillin component (84.4 mg/kg/dose piperacillin; tazobactam) (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) IV every 6 hours for at least 14 days; may consider step-down to oral therapy.
Immunocompromised Infants, Children, and Adolescents: 75 mg/kg/dose piperacillin component (84.4 mg/kg/dose piperacillin; tazobactam) (Max: 4 g/dose piperacillin [4.5 g/dose piperacillin; tazobactam]) IV every 6 hours for at least 14 days; may consider step-down to oral therapy. Transition to a postexposure prophylaxis regimen to complete a 60-day total treatment course from illness onset.

Maximum Dosage Limits:
-Neonates
30 weeks postmenstrual age and younger: Safety and efficacy have not been established; however, doses up to 300 mg/kg/day piperacillin component (337.5 mg/kg/day piperacillin; tazobactam) IV have been used off-label.
older than 30 weeks postmenstrual age: Safety and efficacy have not been established; however, doses up to 320 mg/kg/day piperacillin component (360 mg/kg/day piperacillin; tazobactam) IV have been used off-label.
-Infants
1 month: Safety and efficacy have not been established; however, doses up to 320 mg/kg/day piperacillin component (360 mg/kg/day piperacillin; tazobactam) IV have been used off-label.
2 to 9 months: 320 mg/kg/day piperacillin component (360 mg/kg/day piperacillin; tazobactam) IV is FDA-approved dosage; however, doses up to 600 mg/kg/day piperacillin component (675 mg/kg/day piperacillin; tazobactam) IV have been used off-label for patients with cystic fibrosis.
10 to 11 months: 400 mg/kg/day piperacillin component (450 mg/kg/day piperacillin; tazobactam) IV is FDA-approved dosage; however, doses up to 600 mg/kg/day piperacillin component (675 mg/kg/day piperacillin; tazobactam) IV have been used off-label for patients with cystic fibrosis.
-Children
weighing 40 kg or less: 400 mg/kg/day piperacillin component (450 mg/kg/day piperacillin; tazobactam) IV is FDA-approved dosage; however, doses up to 600 mg/kg/day piperacillin component (675 mg/kg/day piperacillin; tazobactam) IV have been used off-label for patients with cystic fibrosis.
weighing more than 40 kg: 18 g/day (16 g piperacillin and 2 g tazobactam) IV is FDA-approved dosage; however, doses up to 600 mg/kg/day piperacillin component (675 mg/kg/day piperacillin; tazobactam; Max: 27 g/day [24 g piperacillin and 3 g tazobactam]) IV have been used off-label for patients with cystic fibrosis.
-Adolescents
weighing 40 kg or less: 400 mg/kg/day piperacillin component (450 mg/kg/day piperacillin; tazobactam) IV is FDA-approved dosage; however, doses up to 600 mg/kg/day piperacillin component (675 mg/kg/day piperacillin; tazobactam) IV have been used off-label for patients with cystic fibrosis.
weighing more than 40 kg: 18 g/day (16 g piperacillin and 2 g tazobactam) IV is FDA-approved dosage; however, doses up to 600 mg/kg/day piperacillin component (675 mg/kg/day piperacillin; tazobactam; Max: 27 g/day [24 g piperacillin and 3 g tazobactam]) IV have been used off-label for patients with cystic fibrosis.

Patients with Hepatic Impairment Dosing
Patients with hepatic cirrhosis experience increases in the half-life of piperacillin and tazobactam by approximately 25% and 18%, respectively, compared to healthy subjects. However, dosage adjustments are not required.

Patients with Renal Impairment Dosing
Conventional intermittent dosing
In pediatric patients, recommended dosage adjustments include :
GFR more than 50 mL/minute/1.73 m2: No dosage adjustment needed.
GFR 30 to 50 mL/minute/1.73 m2: 35 to 50 mg/kg/dose (piperacillin component) IV every 6 hours.
GFR 29 mL/minute/1.73 m2 or less: 35 to 50 mg/kg/dose (piperacillin component) IV every 8 hours.

Intermittent hemodialysis
50 to 75 mg/kg/dose (piperacillin component) IV every 12 hours is recommended.. Approximately 30% to 40% of a dose of piperacillin; tazobactam is removed during hemodialysis, with an additional 5% of the tazobactam dose taken out as the metabolite.

Continuous renal replacement therapy (CRRT)
35 to 50 mg/kg/dose (piperacillin component) IV every 8 hours.

Peritoneal dialysis (CAPD)
50 to 75 mg/kg/dose (piperacillin component) IV every 12 hours is recommended. Peritoneal dialysis may account for approximately 6% and 21% of piperacillin and tazobactam doses, respectively, with up to 16% of the tazobactam dose as the metabolite.

Extended-infusion dosing
Although pediatric specific renal dose adjustments are not available for extended-infusion dosing, the following dose adjustments are based on recommendations in adult patients. Similar adjustments should be considered for pediatric patients.
CrCl 20 mL/minute or more: No dosage adjustment needed.
CrCl less than 20 mL/minute: Extend dosing interval to every 12 hours.

Intermittent hemodialysis
Extend dosing interval to every 12 hours.

Continuous renal replacement therapy (CRRT)
Give same dose every 8 hours.

Peritoneal dialysis (CAPD)
Extend dosing interval to every 12 hours.

*non-FDA-approved indication

Monograph content under development

Mechanism of Action: Piperacillin is a beta-lactam antibiotic and is mainly bactericidal. It inhibits the third and final stage of bacterial cell wall synthesis by preferentially binding to specific penicillin-binding proteins (PBPs) that are located inside the bacterial cell wall. PBPs are responsible for several steps in the synthesis of the cell wall and are found in quantities of several hundred to several thousand molecules per bacterial cell. PBPs vary among different bacterial species. Thus, the intrinsic activity of piperacillin, as well as the other penicillins, against a particular organism depends on its ability to gain access to and bind with the necessary PBP. Like all beta-lactam antibiotics, piperacillin's ability to interfere with PBP-mediated cell wall synthesis ultimately leads to cell lysis. Lysis is mediated by bacterial cell wall autolytic enzymes (i.e., autolysins). The relationship between PBPs and autolysins is unclear, but it is possible that the beta-lactam antibiotic interferes with an autolysin inhibitor.

Tazobactam, like sulbactam and clavulanic acid, is an irreversible inhibitor of bacterial beta-lactamases. Tazobactam protects piperacillin against Richmond and Sykes types II, III, IV, and V beta-lactamases; staphylococcal penicillinase; and extended-spectrum beta-lactamases. However, tazobactam has only species-specific activity against class I chromosomally-mediated beta-lactamases. It has little useful antibacterial activity by itself and does not alter the actions of piperacillin.

Beta-lactams exhibit concentration-independent or time-dependent killing. In vitro and in vivo animal studies have demonstrated that the major pharmacodynamic parameter that determines efficacy for beta-lactams is the amount of time free (non-protein bound) drug concentrations exceed the minimum inhibitory concentration (MIC) of the organism (free T above MIC). This microbiological killing pattern is due to the mechanism of action, which is acylation of PBPs. There is a maximum proportion of PBPs that can be acylated; therefore, once maximum acylation has occurred, killing rates cannot increase. Free beta-lactam concentrations do not have to remain above the MIC for the entire dosing interval. The percentage of time required for both bacteriostatic and maximal bactericidal activity is different for the various classes of beta-lactams. Penicillins require free drug concentrations to exceed the MIC for 30% of the dosing interval to achieve bacteriostatic activity and 50% of the dosing interval to achieve bactericidal activity.

The susceptibility interpretive criteria for piperacillin; tazobactam are delineated by pathogen. The MICs are defined for Acinetobacter sp., anaerobes, other non-Enterobacterales, Aeromonas sp., and Vibrio sp. (excluding V. cholerae) as susceptible at 16/4 mcg/mL or less, intermediate at 32/4 to 64/4 mcg/mL, and resistant at 128/4 mcg/mL or more. The Clinical and Laboratory Standards Institute (CLSI) and the FDA differ on MIC interpretation for Enterobacterales and for P. aeruginosa. The MICs are defined by the FDA for Enterobacterales as susceptible at 8/4 mcg/mL or less, intermediate at 16/4, and resistant at 32/4 mcg/mL or more; however, the MICs are defined by the CLSI as susceptible at 8/4 mcg/mL or less, susceptible dose dependent (SDD) at 16/4 mcg/mL, and resistant at 32/4 mcg/mL or more. CLSI breakpoints for susceptible are based on a dosage regimen of 3.375 g (3 g piperacillin and 0.375 g tazobactam) or 4.5 g (4 g piperacillin and 0.5 g tazobactam) IV every 6 hours administered as a 30-minute infusion. CLSI breakpoints for SDD are based on a dosage regimen of 4.5 g (4 g piperacillin and 0.5 g tazobactam) IV administered every 6 hours as a 3-hour infusion or every 8 hours as a 4-hour infusion. The MICs are defined by the FDA for P. aeruginosa as susceptible at 16/4 mcg/mL or less, intermediate at 32/4 to 64/4 mcg/mL, and resistant at 128/4 mcg/mL or more; however, the MICs are defined by the CLSI as susceptible at 16/4 mcg/mL or less, intermediate at 32/4 mcg/mL, and resistant at 64/4 mcg/mL or more [based on a dosage regimen of 4.5 g (4 g piperacillin and 0.5 g tazobactam) IV every 6 hours administered as a 30-min or 3-hour infusion]. The MICs are defined for H. influenzae and H. parainfluenzae as susceptible at 1/4 mcg/mL or less and resistant at 2/4 mcg/mL or more. Enterococci susceptible to penicillin are predictably susceptible to piperacillin; tazobactam for non-beta-lactamase producing enterococci. Considering site of infection and appropriate piperacillin; tazobactam dosing, oxacillin-susceptible staphylococci can be considered susceptible to piperacillin; tazobactam.

Pharmacokinetics: Piperacillin; tazobactam is administered intravenously as an infusion. Both piperacillin and tazobactam are approximately 30% bound to plasma protein and are unaffected by the presence of each other. Protein binding of the tazobactam metabolite is negligible. Piperacillin and tazobactam are widely distributed into tissues and body fluids including the intestinal mucosa, lung, female reproductive tissues, interstitial fluid, and bile. Mean tissue concentrations are generally 50-100% of those in plasma. Minimal concentrations are reached within the CSF when the meninges are uninflamed; concentrations increase in the presence of inflammation.

Piperacillin is metabolized to a minor active desethyl metabolite. Tazobactam is metabolized to a single metabolite that lacks pharmacological and antibacterial activity. Both piperacillin and tazobactam are excreted into the urine primarily via tubular secretion and glomerular filtration. Approximately 68% of piperacillin and 80% of tazobactam are excreted as unchanged drug. Piperacillin, tazobactam, and desethyl piperacillin are also secreted into the bile.

Affected cytochrome P450 isoenzymes: none


-Route-Specific Pharmacokinetics
Intravenous Route
Peak serum concentrations are attained immediately after the completion of the infusion. Piperacillin concentrations obtained after administration of piperacillin; tazobactam are similar to those attained when equivalent doses of piperacillin alone are administered. Steady state serum concentrations are similar to those attained after the first dose. The half-life of piperacillin and tazobactam was unaffected by dose or duration of infusion.


-Special Populations
Pediatrics
Premature Neonates
There are limited pharmacokinetic data in neonates with piperacillin; tazobactam. Data on piperacillin are based on studies using the single compound. The mean elimination half-life of piperacillin has been reported to range from 147-258 minutes after a single IV dose of 75 mg/kg with the half-life decreasing with increasing postnatal age. The changes in half-life appear to be due to an immature renal system during the first weeks of life. In a pharmacokinetic study using piperacillin 75 mg/kg IV (n=8), peak serum concentrations and the half-life decreased from the first to the second week of life. Mean peak serum concentrations were lower during both time frames for neonates with gestational age of < 33 weeks (n=11) as compared to those with a gestational age of 33-36 weeks (n=15) and infants with a gestational age of > 36 weeks (n=8). This difference may be related to changes in extracellular fluid volumes noted in premature neonates as compared to full term infants. The half-life in premature neonates decreased with increasing gestational age and postnatal age. The half-life was 4.3 +/- 1.9 hours during week 1 and 3.18 +/-1.35 hours during week 2 for patients < 33 weeks gestational age as compare to 3.35 +/- 0.75 hours during week 1 and 2.45 +/-0.75 hours during week 2 for patients 33-36 weeks gestational age.

Neonates
There are limited pharmacokinetic data in neonates with piperacillin; tazobactam. Data on piperacillin are based on studies using the single compound. The elimination half-life of piperacillin in neonates is twofold to fourfold longer than observed in pediatric patients >= 1 month of age and adults. In one study, the mean elimination half-life ranged from 127-217 minutes after a single IV dose of 50 mg/kg. As with premature neonates, the half-life decreases with increasing postnatal age. After a 5 minute IV infusion of 50 mg/kg, the mean plasma concentration of piperacillin extrapolated to time zero was 141 mcg/ml with an mean apparent volume of distribution of 101 ml/kg. In a pharmacokinetic study using piperacillin 75 mg/kg IV (n=8), peak serum concentrations decreased from a mean of 207 +/- 76 mcg/ml the first to 165 +/-100 ml the second week of life. The half-life also decreased from 2.47 +/- 0.72 hours to 1.65 +/- 0.73 hours during the same time frame.

Infants, Children, and Adolescents
The clearance of piperacillin and tazobactam is slower in younger patients as compared to older children and adults. In a population pharmacokinetic analysis, the estimated clearance for 9 month to 12 year old patients was comparable to adults with a population mean value of 5.64 ml/min/kg. The piperacillin clearance estimate is 80% of this value in pediatric patients 2-9 months of age. The piperacillin half-life of patients > 6 months of age ranged from 0.7-0.9 hours and increased to 1.4 hours in those < 6 months of age. In patients younger than 2 months old, the clearance of piperacillin slower compared to older children. Tazobactam clearance and half-life measurements follow a similar pattern among age groups. The population mean volume of distribution (Vd) is 0.234 L/kg and is independent of age.

Hepatic Impairment
The elimination half-life of piperacillin and tazobactam increases by 25% and 18%, respectively, in patients with hepatic cirrhosis. In patients with combined renal and hepatic dysfunction, the elimination half-life may be significantly increased.

Renal Impairment
The half-life of piperacillin; tazobactam increases as the creatinine clearance decreases. In the general population, at creatinine clearances below 20 ml/min, there is a twofold and fourfold increase in elimination half-life for piperacillin and tazobactam, respectively. In patients with combined renal and hepatic dysfunction, the elimination half-life may be significantly increased. Approximately 30-40% of an administered piperacillin; tazobactam dose is removed by hemodialysis, with an additional 5% of the tazobactam dose taken out as the metabolite. Peritoneal dialysis may account for approximately 6% and 21% of piperacillin and tazobactam doses, respectively, with up to 16% of the tazobactam dose as the metabolite.

Other
Cystic fibrosis
In cystic fibrosis patients < 12 years of age, bioavailability is increased, serum concentrations are lower, and total body clearance of piperacillin is increased as compared to healthy volunteers.