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Ceftolozane/Tazobactam (Monograph)

Drug class: Third Generation Cephalosporins
Chemical name: 5-Amino-4-[[[(2-aminoethyl)amino]carbonyl]amino]-2-[[(6R,7R)-7-[[(2Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-[(1-carboxy-1-methylethoxy)imino]acetyl]amino]-2-carboxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-3-yl]methyl]-1-methyl-1H-pyrazolium sulfate (1:1)
Molecular formula: C23H31N12O8S2+ • HO4S-C10H11N4NaO5S
CAS number: 936111-69-2

Medically reviewed by on Oct 10, 2022. Written by ASHP.


Antibacterial; β-lactam antibiotic; fixed combination of ceftolozane (a third generation cephalosporin) and tazobactam (a β-lactamase inhibitor).

Uses for Ceftolozane/Tazobactam

Intra-abdominal Infections

Treatment of complicated intra-abdominal infections caused by susceptible Enterobacter colacae, Escherichia coli, Klebsiella oxytoca, K. pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Bacteroides fragilis, Streptococcus anginosus, S. constellatus, or S. salivarius; used in conjunction with metronidazole.

Urinary Tract Infections

Treatment of complicated urinary tract infections, including pyelonephritis, caused by susceptible E. coli, K. pneumoniae, P. mirabilis, or Ps. aeruginosa.

Ceftolozane/Tazobactam Dosage and Administration


Administer by IV infusion.

IV Administration

For solution compatibility information, see Compatibility under Stability.

Do not admix with or add to solutions containing other drugs.


Reconstitute single-dose vials of ceftolozane and tazobactam labeled as containing 1.5 g (ceftolozane 1 g and tazobactam 0.5 g) by adding 10 mL of sterile water for injection or 0.9% sodium chloride injection to the vial; shake gently until contents dissolve.


Prior to IV infusion, reconstituted solution must be further diluted.

To prepare indicated dose, withdraw appropriate volume of reconstituted solution from the vial and add to 100 mL of 0.9% sodium chloride or 5% dextrose injection. (See Table 1.) Solution should appear clear and colorless to slightly yellow.

Table 1. Dilution of Reconstituted Ceftolozane and Tazobactam1

Recommended Dose of Ceftolozane and Tazobactam

Volume to Withdraw from Reconstituted Vial for Further Dilution

1.5 g (ceftolozane 1 g and tazobactam 0.5 g)

11.4 mL (entire contents)

750 mg (ceftolozane 500 mg and tazobactam 250 mg)

5.7 mL

375 mg (ceftolozane 250 mg and tazobactam 125 mg)

2.9 mL

150 mg (ceftolozane 100 mg and tazobactam 50 mg)

1.2 mL

Rate of Administration

Administer by IV infusion over 1 hour.

Dispensing and Dosage and Administration Precautions

FDA alerted healthcare professionals about risk of medication errors with ceftolozane and tazobactam. Errors occurred during preparation of solutions for IV infusion, resulted in administration of incorrect dosage (50% overdosage in some cases), and were due to confusion about how dosage of the fixed combination is expressed (total of the dosage of each of the 2 active components) and how drug strength was displayed on vial labels and carton packaging. To prevent such errors, vial labels and carton packaging were revised to indicate strength of the fixed combination as the total the 2 active components.

Be aware that dosage of ceftolozane and tazobactam is expressed as the total (sum) of the dosage of each of the 2 active components (i.e., dosage of ceftolozane plus dosage of tazobactam). Consider this dosage convention when prescribing, preparing, and dispensing ceftolozane and tazobactam. FDA urges healthcare professionals and patients to report medication errors and adverse effects involving the drug to the FDA MedWatch program.


Available as fixed combination containing 2:1 ratio of ceftolozane to tazobactam.

Ceftolozane component provided as ceftolozane sulfate (dosage of this component expressed in terms of ceftolozane); tazobactam component provided as tazobactam sodium (dosage of this component expressed in terms of tazobactam).

Dosage of ceftolozane and tazobactam fixed combination expressed in terms of the total of the ceftolozane and tazobactam content.

Each single-dose vial contains a total of 1.5 g (i.e., 1 g of ceftolozane and 0.5 g of tazobactam).


Intra-abdominal Infections

1.5 g (ceftolozane 1 g and tazobactam 0.5 g) every 8 hours given in conjunction with metronidazole (500 mg IV every 8 hours).

Recommended treatment duration is 4–14 days. Duration depends on site and severity of infection and patient’s clinical and bacteriologic progress.

Urinary Tract Infections

1.5 g (ceftolozane 1 g and tazobactam 0.5 g) every 8 hours.

Recommended treatment duration is 7 days. Duration depends on site and severity of infection and patient’s clinical and bacteriologic progress.

Special Populations

Hepatic Impairment

Dosage adjustments not needed in adults with hepatic impairment.

Renal Impairment

Adjust dosage in adults with Clcr ≤50 mL/minute, including those undergoing hemodialysis. (See Table 2.)

Monitor Clcr at least once daily in patients with changing renal function; adjust dosage accordingly.

On hemodialysis days, administer dose as soon as possible after dialysis.

Table 2. Ceftolozane and Tazobactam Dosage for Adults with Renal Impairment1

Estimated Clcr (mL/minute)

Recommended Dosage


750 mg (ceftolozane 500 mg and tazobactam 250 mg) every 8 hours


375 mg (ceftolozane 250 mg and tazobactam 125 mg) every 8 hours

End-stage renal disease on hemodialysis

Single loading dose of 750 mg (ceftolozane 500 mg and tazobactam 250 mg) followed by maintenance dosage of 150 mg (ceftolozane 100 mg and tazobactam 50 mg) every 8 hours

Geriatric Patients

Dosage adjustments based solely on age not needed. Select dosage with caution and monitor renal function since geriatric patients more likely to have decreased renal function than younger adults.

Cautions for Ceftolozane/Tazobactam


  • Known serious hypersensitivity to ceftolozane and/or tazobactam, the fixed combination of piperacillin and tazobactam, or other β-lactams.


Sensitivity Reactions

Serious and occasionally fatal hypersensitivity (anaphylactic) reactions reported in patients receiving β-lactam antibacterials. Before initiating therapy, carefully inquire about patient's previous hypersensitivity reactions to other cephalosporins, penicillins, or other β-lactams.

Use with caution in patients allergic to cephalosporins, penicillins, or other β-lactams; cross-sensitivity among β-lactams established.

If anaphylactic reaction occurs, discontinue ceftolozane and tazobactam and initiate appropriate therapy.

Reduced Efficacy in Patients with Moderate Renal Impairment

In a subgroup analysis of patients with complicated intra-abdominal infections in a phase 3 clinical trial, clinical cure rate in patients with moderate renal impairment (baseline Clcr of 30–50 mL/minute) receiving ceftolozane and tazobactam in conjunction with metronidazole was 47.8% compared with a clinical cure rate of 85.2% in those with normal renal function or only mild renal impairment (Clcr ≥50 mL/minute). A similar trend also observed in a clinical trial evaluating ceftolozane and tazobactam for complicated urinary tract infections.

Monitor Clcr at least once daily in patients with changing renal function; adjust dosage accordingly. (See Renal Impairment under Cautions.)

Superinfection/Clostridium difficile-associated Diarrhea and Colitis (CDAD)

Possible emergence and overgrowth of nonsusceptible bacteria or fungi. Monitor carefully, institute appropriate therapy if superinfection occurs.

Treatment with anti-infectives alters normal colon flora and may permit overgrowth of Clostridium difficile. C. difficile infection (CDI) and C. difficile-associated diarrhea and colitis (CDAD; also known as antibiotic-associated diarrhea and colitis or pseudomembranous colitis) reported with nearly all anti-infectives, including ceftolozane and tazobactam, and may range in severity from mild diarrhea to fatal colitis. C. difficile produces toxins A and B which contribute to development of CDAD; hypertoxin-producing strains of C. difficile are associated with increased morbidity and mortality since they may be refractory to anti-infectives and colectomy may be required.

Consider CDAD if diarrhea develops during or after therapy and manage accordingly. Obtain careful medical history since CDAD may occur as late as ≥2 months after anti-infective therapy is discontinued.

If CDAD suspected or confirmed, discontinue anti-infectives not directed against C. difficile whenever possible. Initiate appropriate supportive therapy (e.g., fluid and electrolyte management, protein supplementation), anti-infective therapy directed against C. difficile (e.g., metronidazole, vancomycin), and surgical evaluation as clinically indicated.

Selection and Use of Anti-infectives

To reduce development of drug-resistant bacteria and maintain effectiveness of ceftolozane and tazobactam and other antibacterials, use only for treatment or prevention of infections proven or strongly suspected to be caused by susceptible bacteria.

When selecting or modifying anti-infective therapy, use results of culture and in vitro susceptibility testing. In the absence of such data, consider local epidemiology and susceptibility patterns when selecting anti-infectives for empiric therapy.

Use of Fixed Combinations

Consider cautions, precautions, contraindications, and drug interactions associated with both drugs in the fixed combination. Consider cautionary information applicable to specific populations (e.g., pregnant or nursing women, individuals with hepatic or renal impairment, geriatric patients) for both drugs.

When prescribing, preparing, and dispensing ceftolozane and tazobactam, consider that dosage of the fixed combination is expressed as the total (sum) of the dosage of each of the 2 active components (i.e., dosage of ceftolozane plus dosage of tazobactam). (See Dispensing and Dosage and Administration Precautions under Dosage and Administration.)

Specific Populations


Category B.

Use during pregnancy only if potential benefits to the woman justify potential risks to fetus.

No adequate and well-controlled studies in pregnant women. In animals, no evidence of fetal toxicity with ceftolozane or tazobactam dosages tested; ceftolozane associated with decreased auditory startle response in postnatal day 60 male pups; tazobactam associated with decreased maternal food consumption and body weight gain at end of gestation and increased incidence of stillbirths.


Not known whether ceftolozane or tazobactam distributed into human milk.

Use with caution in nursing women.

Pediatric Use

Safety and efficacy not established in patients <18 years of age.

Geriatric Use

Incidence of adverse effects higher in patients ≥65 years of age compared with younger adults.

Clinical cure rate in geriatric patients treated with ceftolozane and tazobactam in conjunction with metronidazole for complicated intra-abdominal infections was 69% compared with cure rate of 82.4% in comparator group. Differences in cure rates between ceftolozane and tazobactam regimen and comparator regimen not observed in geriatric patients with complicated urinary tract infections.

Ceftolozane and tazobactam substantially eliminated by kidneys; risk of adverse effects may be greater in those with impaired renal function. Because geriatric patients are more likely to have reduced renal function, select dosage with caution and consider renal function monitoring. Adjust dosage in geriatric patients based on renal function.

Hepatic Impairment

Ceftolozane and tazobactam do not undergo hepatic metabolism; hepatic impairment not expected to affect systemic clearance.

Renal Impairment

Ceftolozane, tazobactam, and tazobactam metabolite M1 are eliminated by the kidneys.

Adjust dosage in adults with moderate or severe renal impairment (Clcr ≤50 mL/minute), including those undergoing hemodialysis. Monitor Clcr at least once daily in patients with changing renal function; adjust dosage accordingly. (See Renal Impairment under Dosage and Administration.)

Common Adverse Effects

GI effects (nausea, diarrhea ), headache, pyrexia.

Interactions for Ceftolozane/Tazobactam

Ceftolozane, tazobactam, and tazobactam metabolite M1 do not inhibit CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, or 3A4 and do not induce CYP1A2, 2B6, or 3A4 in vitro. In vitro, ceftolozane, tazobactam, and M1 decreased CYP1A2 and 2B6 enzyme activity and mRNA levels in human hepatocytes. Ceftolozane, tazobactam, and M1 decreased CYP3A4 mRNA levels in vitro at supratherapeutic plasma concentrations; M1 decreased CYP3A4 activity at supratherapeutic plasma concentrations.

Tazobactam is a substrate of organic anion transporter (OAT) 1 and OAT3.

Tazobactam inhibits OAT1 and OAT3 in vitro; ceftolozane does not inhibit OAT1 or OAT3.

Ceftolozane and tazobactam not substrates or inhibitors of P-glycoprotein (P-gp) or breast cancer resistance protein (BCRP); tazobactam not a substrate of organic cation transporter (OCT) 2.

Ceftolozane and tazobactam do not inhibit organic anion transporting polypeptide (OATP) 1B1 or 1B3, or OCT1 or OCT2, or bile salt export pump (BSEP) at therapeutic plasma concentrations.

Ceftolozane does not inhibit multidrug resistance-associated protein (MRP) or multidrug and toxin extrusion (MATE) 1 or 2-K.

The following drug interactions are based on studies using ceftolozane and tazobactam, ceftolozane alone, or tazobactam alone. When ceftolozane and tazobactam used, consider interactions associated with both drugs in the fixed combination.

Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes

CYP enzyme inhibitors or inducers: Drug interactions not expected.

Drugs Affecting or Affected by Organic Anion Transporters

OAT1 and/or OAT3 inhibitors: Possible increased tazobactam plasma concentrations.

OAT1 or OAT3 substrates: Clinically important interactions not expected.

Specific Drugs




No in vitro evidence of antagonistic antibacterial effects

Other anti-infectives (amikacin, aztreonam, daptomycin, levofloxacin, linezolid, meropenem, rifampin, tigecycline, vancomycin)

No in vitro evidence of antagonistic effects


Concomitant use of probenecid (OAT1/OAT3 inhibitor) and tazobactam prolongs tazobactam half-life by 71%

Ceftolozane/Tazobactam Pharmacokinetics


Following IV administration of fixed combination of ceftolozane and tazobactam, pharmacokinetic parameters for ceftolozane and tazobactam are similar to those reported when each drug is administered alone.

Pharmacokinetic parameters are similar following single or multiple IV doses of the fixed combination.

Plasma Concentrations

Peak plasma concentrations and AUCs of both ceftolozane and tazobactam increase in proportion to dose of the fixed combination.

Peak plasma concentrations of ceftolozane and tazobactam are 74.4 and 18 mcg/mL, respectively, in healthy adults with normal renal function following multiple doses of ceftolozane and tazobactam (1.5 g [ceftolozane 1 g and tazobactam 0.5 g]) given by IV infusion over 1 hour every 8 hours for 10 days.

No appreciable accumulation of ceftolozane or tazobactam in adults with normal renal function when the fixed combination is given by IV infusion every 8 hours for 10 days.

Special Populations

In a population pharmacokinetic analysis, age, gender, and race did not result in clinically important differences in ceftolozane and tazobactam exposures.



Steady-state volumes of distribution suggest that both drugs distribute into extracellular space.

Ceftolozane and tazobactam both distributed into pulmonary epithelial lining fluid following IV administration in healthy adults.

Not known whether ceftolozane crosses placenta. In rats, tazobactam crosses placenta; fetal concentrations in rats are ≤10% of maternal plasma concentrations.

Not known whether ceftolozane or tazobactam distributes into human milk.

Plasma Protein Binding

Ceftolozane: Approximately 16–21%.

Tazobactam: 30%.



Ceftolozane not metabolized to any appreciable extent; tazobactam partially metabolized by hydrolysis of the β-lactam ring to form an inactive metabolite, M1.

Ceftolozane and tazobactam not substrates of CYP isoenzymes.

Elimination Route

Ceftolozane, tazobactam, and M1 eliminated by the kidneys.

Following single IV dose of ceftolozane and tazobactam (1.5 g [ceftolozane 1 g and tazobactam 0.5 g]) in healthy adult males, >95% of ceftolozane dose eliminated in urine unchanged and >80% of tazobactam dose eliminated in urine unchanged (remainder eliminated as M1).


Ceftolozane: Approximately 3 hours.

Tazobactam: Approximately 1 hour.

Special Populations

Mild, moderate, or severe renal impairment: Dose-normalized geometric mean AUC of ceftolozane increased by 1.26-, 2.5-, or 5-fold, respectively; tazobactam dose-normalized geometric mean AUC increased by 1.3-, 2-, or 4-fold, respectively.

Both ceftolozane and tazobactam removed by hemodialysis. In adults with end-stage renal disease, a 4-hour hemodialysis session decreases AUCs of ceftolozane and tazobactam by approximately 66 and 56%, respectively.




Powder for IV Infusion

2–8°C. Protect from light.

Reconstituted solution may be stored for up to 1 hour prior to further dilution; do not freeze.

Following reconstitution and dilution, may be stored for up to 24 hours at room temperature or up to 7 days when refrigerated at 2–8°C. Do not freeze.


For information on systemic interactions resulting from concomitant use, see Interactions.


Solution Compatibility


Dextrose 5%

Sodium chloride 0.9%

Actions and Spectrum

  • Ceftolozane and tazobactam is a fixed combination of ceftolozane (a third generation cephalosporin) and tazobactam (a β-lactamase inhibitor).

  • Like other cephalosporins, antibacterial activity of ceftolozane results from inhibition of mucopeptide synthesis in bacterial cell wall and is mediated by penicillin-binding proteins (PBPs). Ceftolozane has an expanded spectrum of activity against gram-negative bacteria compared with first and second generation cephalosporins, and is distinguished from many other cephalosporins by its activity against Ps. aeruginosa.

  • Tazobactam is a penicillanic acid sulfone β-lactamase inhibitor structurally similar to sulbactam. Tazobactam inactivates certain β-lactamases, including some extended-spectrum β-lactamases (ESBLs). Inactivates many β-lactamases in Ambler class A (e.g., penicillinases, ESBLs) and some in class C (e.g., cephalosporinases such as AmpC). Cannot inactivate Ambler class A carbapenemases (e.g., K. pneumoniae carbapenemases [KPCs]), Ambler class D β-lactamases, or Ambler class B metallo-β-lactamases (MLBs).

  • Because tazobactam inactivates certain β-lactamases, concomitant use with ceftolozane can protect ceftolozane from degradation by these β-lactamases and expand its spectrum of activity to include many β-lactamase-producing bacteria resistant to ceftolozane alone.

  • Ceftolozane and tazobactam is bactericidal in action.

  • Gram-positive aerobes: Active in vitro against S. anginosus, S. constellatus, S. salivarius, S. agalactiae, S. intermedius, S. pyogenes, and S. pneumoniae.

  • Gram-negative aerobes: Active in vitro against Enterobacteriaceae, including E. aerogenes, E. cloacae, E. coli, K. oxytoca, K. pneumoniae, P. mirabilis, P. vulgaris, C. freundii, K. koseri, Morganella morganii, Providencia rettgeri, P. stuartii, Serratia liquefacians, and S. marcescens. Active in vitro against Acinetobacter baumannii, Burkholderia cepacia, Haemophilus influenzae, Moraxella catarrhalis, and Pantoea agglomerans. Also active in vitro against Ps. aeruginosa (including isolates with chromosomal AmpC, loss of outer membrane porin [OprD], or up-regulation of efflux pumps [e.g., MexXY, MexAB]).

  • Anaerobic bacteria: Active in vitro against some strains of B. fragilis, Fusobacterium, Prevotella, and Propionibacterium.

  • Resistance or reduced susceptibility to ceftolozane and tazobactam can occur.

  • Bacteria that produce Ambler class B metallo-β-lactamases or serine carbapenemases (such as KPC) are resistant to ceftolozane and tazobactam. Although some isolates of E. coli and K. pneumoniae producing β-lactamases in certain enzyme groups (e.g., CTX-M, OXA, TEM, SHV) are susceptible to ceftolozane and tazobactam in vitro, other isolates of E. coli and K. pneumoniae producing β-lactamases in these enzyme groups are resistant to the drug. Ps. aeruginosa with reduced susceptibility or resistance to ceftolozane and tazobactam have been produced in vitro.

  • Cross-resistance between ceftolozane and tazobactam and other cephalosporins may occur; however, some bacteria resistant to other cephalosporins may be susceptible to the fixed combination.

Advice to Patients

  • Advise patients that antibacterials (including ceftolozane and tazobactam) should only be used to treat bacterial infections and not used to treat viral infections (e.g., the common cold).

  • Importance of completing full course of therapy, even if feeling better after a few days.

  • Advise patients that skipping doses or not completing the full course of therapy may decrease effectiveness and increase the likelihood that bacteria will develop resistance and will not be treatable with ceftolozane and tazobactam or other antibacterials in the future.

  • Advise patients that allergic reactions, including serious allergic reactions, could occur and that serious reactions require immediate treatment.

  • Importance of informing clinicians of prior hypersensitivity reactions to ceftolozane and tazobactam, other β-lactam antibiotics, or other allergens. Importance of discontinuing the drug and immediately and informing clinician if an allergic or hypersensitivity reaction occurs.

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal supplements, as well as any concomitant illnesses.

  • Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.

  • Importance of informing patients of other important precautionary information. (See Cautions.)


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Ceftolozane Sulfate and Tazobactam Sodium


Dosage Forms


Brand Names



For injection, for IV infusion

1.5 g (1 g of ceftolozane and 0.5 g of tazobactam)



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