There is no experience with overdose of Zerbaxa. The highest single dose of Zerbaxa used in clinical trials was 3 g / 1.5 g of ceftolozane/tazobactam administered to healthy volunteers.
In the event of overdose, Zerbaxa should be discontinued and general supportive treatment given. Zerbaxa can be removed by haemodialysis. Approximately 66% of ceftolozane, 56% of tazobactam, and 51% of the M1 metabolite of tazobactam were removed by dialysis.
30 months.
After reconstitution, chemical and physical in-use stability has been demonstrated for 4 days at 2 to 8°C. The medicinal product is photosensitive and should be protected from light when not stored in the original carton.
From a microbiological point of view, the medicinal product should be used immediately upon reconstitution. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user, unless reconstitution/dilution has taken place in controlled and validated aseptic conditions and would normally not be longer than 24 hours at 2 to 8°C.
- ;
- Hypersensitivity to any cephalosporin antibacterial agent;
- Severe hypersensitivity (e.g., anaphylactic reaction, severe skin reaction) to any other type of beta-lactam antibacterial agent (e.g., penicillins or carbapenems).
Sodium chloride
Arginine
Citric acid, anhydrous
Powder for concentrate for solution for infusion
(powder for concentrate).
White to yellowish powder.
Summary of the safety profile
Zerbaxa was evaluated in Phase 3 comparator-controlled clinical trials of complicated intra-abdominal infections and complicated urinary tract infections (including pyelonephritis), which included a total of 1,015 patients, treated with Zerbaxa (1 g / 0.5 g intravenously every 8 hours, adjusted to match renal function where appropriate) for up to 14 days.
The most common adverse reactions (> 3% in pooled Phase 3 trials) occurring in patients receiving Zerbaxa were nausea, headache, constipation, diarrhoea, and pyrexia and were generally mild or moderate in severity.
Tabulated list of adverse reactions
The following adverse reactions have been identified during clinical trials with Zerbaxa. Adverse reactions are classified according to MedDRA System Organ Class and frequency. Frequency categories are derived according to the following conventions: common (> 1/100 to < 1/10), uncommon (> 1/1,000 to < 1/100) (see Table 3).
Table 3: Adverse reactions identified during clinical trials with ceftolozane/tazobactam (N=1,015)
| System organ class | Common (> 1/100 to < 1/10) | Uncommon (> 1/1,000 to < 1/100) |
| Infections and infestations | Candidiasis including oropharyngeal and vulvovaginal, Clostridium difficile colitis, fungal urinary tract infection | |
| Blood and the lymphatic system disorders | Thrombocytosis | Anaemia |
| Metabolism and nutrition disorders | Hypokalemia | Hyperglycaemia, hypomagnesaemia, hypophosphataemia |
| Psychiatric disorders | Insomnia, anxiety | |
| Nervous system disorders | Headache, dizziness | Ischaemic stroke |
| Cardiac disorders | Atrial fibrillation, tachycardia, angina pectoris | |
| Vascular disorders | Hypotension | Phlebitis, venous thrombosis |
| Respiratory, thoracic, and mediastinal disorders | Dyspnoea | |
| Gastrointestinal disorders | Nausea, diarrhoea, constipation, vomiting, abdominal pain | Gastritis, abdominal distension, dyspepsia, flatulence, ileus paralytic |
| Skin and subcutaneous tissue disorders | Rash | Urticaria |
| Renal and urinary disorders | Renal impairment, renal failure | |
| General disorders and administration site conditions | Pyrexia, infusion site reactions | |
| Investigations | Alanine aminotransferase increased, Aspartate aminotransferase increased | Coombs test positive, increased serum gamma-glutamyl transpeptidase (GGT), increased serum alkaline phosphatase |
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.
Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity or genotoxicity. Carcinogenicity studies with ceftolozane/tazobactam have not been conducted.
Effects in non-clinical studies were observed only at exposures considered sufficiently in excess of the maximum human exposure indicating little relevance to clinical use.
Adverse reactions not observed in clinical studies, but seen in animals at exposure levels similar to clinical exposure levels and with possible relevance to clinical use were as follows: ceftolozane administered to rats during pregnancy and lactation was associated with a decrease in auditory startle response in postnatal day (PND) 60 male pups at maternal doses of 300 and 1,000 mg/kg/day. A dose of 300 mg/kg/day to rats was associated with a ceftolozane plasma exposure (AUC) value approximately equivalent to the ceftolozane plasma AUC value at the human therapeutic dose.
Peri/postnatal development was impaired (reduced pup weights, increase in stillbirths, increase in pup mortality) concurrent with maternal toxicity after intraperitoneal administration of tazobactam in the rat.
Zerbaxa is indicated for the treatment of the following infections in adults :
- Complicated intra-abdominal infections ;
- Acute pyelonephritis;
- Complicated urinary tract infections.
Consideration should be given to official guidance on the appropriate use of antibacterial agents.
Pharmacotherapeutic group: Antibacterials for systemic use, other cephalosporins and penems, ATC code: J01DI54.
Mechanism of action
Ceftolozane belongs to the cephalosporin class of antimicrobials. Ceftolozane exerts bactericidal activity through binding to important penicillin-binding proteins (PBPs), resulting in inhibition of bacterial cell-wall synthesis and subsequent cell death.
Tazobactam is a beta-lactam structurally related to penicillins. It is an inhibitor of many Molecular Class A beta-lactamases, including CTX-M, SHV, and TEM enzymes. See below.
Mechanisms of resistance
Mechanisms of bacterial resistance to ceftolozane/tazobactam include:
i. Production of beta-lactamases that can hydrolyse ceftolozane and which are not inhibited by tazobactam (see below)
ii. Modification of PBPs
Tazobactam does not inhibit all Class A enzymes.
In addition tazobactam does not inhibit the following types of beta-lactamase:
i. AmpC enzymes (produced by Enterobacteriaceae)
ii. Serine-based carbapenemases (e.g., Klebsiella pneumoniae carbapenemases [KPCs])
iii. Metallo-beta-lactamases (e.g., New Delhi metallo-beta-lactamase [NDM])
iv. Ambler Class D beta-lactamases (OXA-carbapenemases)
Pharmacokinetic/pharmacodynamic relationships
For ceftolozane the time that the plasma concentration exceeds the minimum inhibitory concentration of ceftolozane for the infecting organism has been shown to be the best predictor of efficacy in animal models of infection.
For tazobactam the PD index associated with efficacy was determined to be the percentage of the dose interval during which the plasma concentration of tazobactam exceeds a threshold value (%T>threshold). The threshold concentration required is dependent on the organism and the amount and type of β-lactamase produced.
Susceptibility testing breakpoints
Minimum inhibitory concentration breakpoints established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) are as follows:
| Minimum Inhibitory Concentrations (mg/L) | ||
| Pathogen | Susceptible | Resistant |
| Enterobacteriaceae | ≤ 1 | > 1 |
| P. aeruginosa | ≤ 4 | > 4 |
Clinical efficacy against specific pathogens
Efficacy has been demonstrated in clinical studies against the pathogens listed under each indication that were susceptible to Zerbaxa in vitro:
Complicated intra-abdominal infections
Gram-negative bacteria
Enterobacter cloacae
Escherichia coli
Klebsiella oxytoca
Klebsiella pneumoniae
Proteus mirabilis
Pseudomonas aeruginosa
Gram-positive bacteria
Streptococcus anginosus
Streptococcus constellatus
Streptococcus salivarius
Complicated Urinary Tract Infections, including pyelonephritis
Gram-negative bacteria
Escherichia coli
Klebsiella pneumoniae
Proteus mirabilis
Clinical efficacy has not been established against the following pathogens although in vitro studies suggest that they would be susceptible to Zerbaxa in the absence of acquired mechanisms of resistance:
Citrobacter freundii
Citrobacter koseri
Enterobacter aerogenes
Morganella morganii
Proteus vulgaris
Serratia liquefacians
Serratia marcescens
In vitro data indicate that the following species are not susceptible to ceftolozane/tazobactam:
Staphylococcus aureus
Enterococcus faecalis
Enterococcus faecium
Paediatric population
The European Medicines Agency has deferred the obligation to submit the results of studies with Zerbaxa in one or more subsets of the paediatric population in complicated intra-abdominal infection and complicated urinary tract infection (see section 4.2 for information on paediatric use).
The Cmax and AUC of ceftolozane/tazobactam increase approximately in proportion to dose within ceftolozane single-dose range of 250 mg to 3 g and tazobactam single-dose range of 500 mg to 1.5 g. No appreciable accumulation of ceftolozane/tazobactam is observed following multiple 1-hour IV infusions of 1 g / 0.5 g ceftolozane/tazobactam administered every 8 hours for up to 10 days in healthy adults with normal renal function. The elimination half-life (t½) of ceftolozane is independent of dose.
Distribution
The binding of ceftolozane and tazobactam to human plasma proteins is low (approximately 16% to 21% and 30%, respectively). The mean (coefficient of variation CV%) steady-state volume of distribution of ceftolozane/tazobactam in healthy adult males (n = 51) following a single 1 g / 0.5 g IV dose was 13.5 L (21%) and 18.2 L (25%) for ceftolozane and tazobactam, respectively, similar to extracellular fluid volume.
Biotransformation
Ceftolozane is eliminated in the urine as unchanged parent substance and thus does not appear to be metabolised to any appreciable extent. The beta-lactam ring of tazobactam is hydrolyzed to form the pharmacologically inactive, tazobactam metabolite M1.
Elimination
Ceftolozane, tazobactam and the tazobactam metabolite M1 are eliminated by the kidneys. Following administration of a single 1 g / 0.5 g IV dose of ceftolozane/tazobactam to healthy male adults greater than 95% of ceftolozane was excreted in the urine as unchanged parent substance. More than 80% of tazobactam was excreted as the parent compound with the remaining amount excreted as the tazobactam M1 metabolite. After a single dose of ceftolozane/tazobactam, renal clearance of ceftolozane (3.41 - 6.69 L/h) was similar to plasma clearance (4.10 - 6.73 L/h) and similar to the glomerular filtration rate for the unbound fraction, suggesting that ceftolozane is eliminated by the kidney via glomerular filtration.
The mean terminal elimination half-life of ceftolozane and tazobactam in healthy adults with normal renal function is approximately 3 hours and 1 hour, respectively.
Linearity/non-linearity
The Cmax and AUC of ceftolozane/tazobactam increase in proportion to dose. Plasma levels of ceftolozane/tazobactam do not increase appreciably following multiple IV infusions of up to 2.0 g / 1.0 g administered every 8 hours for up to 10 days in healthy adults with normal renal function. The elimination half-life (t½) of ceftolozane is independent of dose.
Special populations
Renal impairment
Ceftolozane/tazobactam and the tazobactam metabolite M1 are eliminated by the kidneys.
The ceftolozane dose normalized geometric mean AUC increased up to 1.26-fold, 2.5-fold, and 5-fold in subjects with mild, moderate, and severe renal impairment, respectively, compared to healthy subjects with normal renal function. The respective tazobactam dose normalized geometric mean AUC increased approximately up to 1.3-fold, 2-fold, and 4-fold. To maintain similar systemic exposures to those with normal renal function, dosage adjustment is required .
In subjects with end stage renal disease on haemodialysis, approximately two-thirds of the administered ceftolozane/tazobactam dose is removed by haemodialysis. The recommended dose in subjects with end stage renal disease on haemodialysis is a single loading dose of 500 mg / 250 mg ceftolozane/tazobactam followed by a 100 mg / 50 mg maintenance dose of ceftolozane/tazobactam administered every 8 hours for the remainder of the treatment period. With haemodialysis, the dose should be administered immediately following completion of dialysis.
Hepatic impairment
As ceftolozane/tazobactam does not undergo hepatic metabolism, the systemic clearance of ceftolozane/tazobactam is not expected to be affected by hepatic impairment. No dose adjustment is recommended for ceftolozane/tazobactam in subjects with hepatic impairment.
Elderly
In a population pharmacokinetic analysis of ceftolozane/tazobactam, no clinically relevant trend in exposure was observed with regard to age. No dose adjustment of ceftolozane/tazobactam based on age alone is recommended.
Paediatric patients
Safety and efficacy in paediatric patients have not been established.
Gender
In a population pharmacokinetic analysis of ceftolozane/tazobactam, no clinically relevant differences in AUC were observed for ceftolozane (116 males compared to 70 females) and tazobactam (80 males compared to 50 females). No dose adjustment is recommended based on gender.
Ethnicity
In a population pharmacokinetic analysis of ceftolozane/tazobactam, no clinically relevant differences in ceftolozane/tazobactam AUC were observed in Caucasians (n = 156) compared to all other ethnicities combined (n = 30). No dose adjustment is recommended based on race.
14 April 2016
Merck Sharp & Dohme Ltd
Hertford Road, Hoddesdon
Hertfordshire EN11 9BU
United Kingdom
Store in a refrigerator (2°C - 8°C).
Store in the original package in order to protect from light.
20 mL vial (Type I clear glass) with stopper (bromobutyl rubber) and flip-off seal.
Pack size of 10 vials.
EU/1/15/1032/001
Pregnancy
There are no data on the use of ceftolozane/tazobactam in pregnant women. Tazobactam crosses the placenta. It is not known if ceftolozane crosses the placenta.
Animal studies with tazobactam have shown reproductive toxicity without evidence of teratogenic effects. Studies with ceftolozane in mice and rats have not shown evidence of reproductive toxicity or teratogenicity. Ceftolozane administered to rats during pregnancy and lactation was associated with a decrease in auditory startle response in postnatal day (PND) 60 male pups.
Zerbaxa should only be used during pregnancy if the expected benefit outweighs the possible risks to the pregnant woman and foetus.
Breast-feeding
It is unknown whether ceftolozane and tazobactam are excreted in human milk. A risk to newborns/infants cannot be excluded. A decision must be made whether to discontinue breast-feeding or to discontinue/abstain from Zerbaxa therapy taking into account the benefit of breast-feeding for the child and the benefit of therapy for the woman.
Fertility
The effects of ceftolozane and tazobactam on fertility in humans have not been studied. Fertility studies in rats showed no effect on fertility and mating after intraperitoneal administration of tazobactam or intravenous administration of ceftolozane.
Each vial contains ceftolozane sulfate equivalent to 1 g ceftolozane and tazobactam sodium equivalent to 0.5 g tazobactam.
After reconstitution with 10 mL diluent, the total volume of the solution in the vial is 11.4 mL, which contains 88 mg/mL of ceftolozane and 44 mg/mL of tazobactam.
Excipient with known effect
Each vial contains 10 mmol (230 mg) of sodium.
When the powder is reconstituted with 10 mL of sodium chloride 9 mg/mL (0.9%) solution for injection, the vial contains 11.5 mmol (265 mg) of sodium.
Hypersensitivity reactions
Serious and occasionally fatal hypersensitivity (anaphylactic) reactions are possible. If a severe allergic reaction occurs during treatment with ceftolozane/tazobactam, the medicinal product should be discontinued and appropriate measures taken.
Patients who have a history of hypersensitivity to cephalosporins, penicillins or other beta-lactam antibacterial agents may also be hypersensitive to ceftolozane/tazobactam.
Ceftolozane/tazobactam is contraindicated in patients with a history of hypersensitivity to ceftolozane, tazobactam, or cephalosporins.
Ceftolozane/tazobactam is also contraindicated in patients with severe hypersensitivity (e.g. anaphylactic reaction, severe skin reaction) to any other type of beta-lactam antibacterial agent (e.g. penicillins or carbapenems).
Ceftolozane/tazobactam should be used with caution in patients with a history of any other type of hypersensitivity reaction to penicillins or other beta-lactam antibacterial agents.
Effect on renal function
A decline in renal function has been seen in patients receiving ceftolozane/tazobactam.
Impaired renal function
The ceftolozane/tazobactam dose should be adjusted based on renal function.
In clinical trials the efficacy of ceftolozane/tazobactam was lower in patients with moderate renal impairment compared with those with normal or mildly impaired renal function at baseline. Patients with renal impairment at baseline should be monitored frequently for any changes in renal function during treatment and the dose of ceftolozane/tazobactam should be adjusted as necessary.
Limitations of the clinical data
Patients who were immunocompromised and patients with severe neutropenia were excluded from clinical trials.
In a trial in patients with complicated intra-abdominal infections, the most common diagnosis was appendiceal perforation or peri-appendiceal abscess (420/970 [43.3%] patients), of which 137/420 (32.6%) had diffuse peritonitis at baseline. Approximately 82% of all patients in the trial had APACHE II (Acute Physiology and Chronic Health Evaluation II) scores of < 10 and 2.3% had bacteraemia at baseline. In the clinically evaluable (CE) patients, the clinical cure rates for ceftolozane/tazobactam were 95.9% in 293 patients aged less than 65 years and 87.8% in 82 patients aged 65 years or more.
Clinical efficacy data in patients with complicated lower urinary tract infection are limited. In a randomised active-controlled trial 18.2% (126/693) of microbiologically evaluable (ME) patients had complicated lower urinary tract infection (cLUTI), including 60/126 patients who were treated with ceftolozane/tazobactam. One of these 60 patients had bacteraemia at baseline.
Clostridium difficile-associated diarrhoea
Antibacterial-associated colitis and pseudomembranous colitis have been reported with ceftolozane/tazobactam. These types of infection may range in severity from mild to life threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhoea during or subsequent to the administration of ceftolozane/tazobactam. In such circumstances, the discontinuation of therapy with ceftolozane/tazobactam and the use of supportive measures together with the administration of specific treatment for Clostridium difficile should be considered.
Non-susceptible micro-organisms
The use of ceftolozane/tazobactam may promote the overgrowth of non-susceptible micro-organisms.
Direct antiglobulin test (Coombs test) seroconversion and potential risk of haemolytic anaemia
The development of a positive direct antiglobulin test (DAGT) may occur during treatment with ceftolozane/tazobactam. The incidence of DAGT seroconversion in patients receiving ceftolozane/tazobactam was 0.2% in the clinical trials. In clinical studies, there was no evidence of haemolysis in patients who developed a positive DAGT on treatment.
Sodium content
Ceftolozane/tazobactam contains 10.0 mmol (230 mg) of sodium per vial. The reconstituted vial with 10 mL of 0.9% sodium chloride (normal saline) for injection contains 11.5 mmol (265 mg) of sodium. This should be taken into consideration while treating patients on controlled-sodium diet.
Zerbaxa may have a minor influence on the ability to drive and use machines. Dizziness may occur following administration of Zerbaxa.
Posology
The recommended intravenous dose regimen for patients with creatinine clearance > 50 mL/min is shown by infection type in Table 1.
Table 1: Intravenous dose of Zerbaxa by type of infection in patients with creatinine clearance > 50 mL/min
| Type of infection | Dose | Frequency | Infusion time | Duration of treatment |
| Complicated intra-abdominal infection* | 1 g ceftolozane / 0.5 g tazobactam | Every 8 hours | 1 hour | 4-14 days |
| Complicated urinary tract infection Acute pyelonephritis | 1 g ceftolozane / 0.5 g tazobactam | Every 8 hours | 1 hour | 7 days |
*To be used in combination with metronidazole when anaerobic pathogens are suspected.
Special populations
Elderly (> 65 years of age)
No dose adjustment is necessary for the elderly based on age alone.
Renal impairment
In patients with mild renal impairment (estimated creatinine clearance [CrCL] > 50 mL/min), no dose adjustment is necessary, see section 5.2).
In patients with moderate or severe renal impairment, and in patients with end stage renal disease on haemodialysis, the dose should be adjusted as listed in Table 2.
Table 2: Intravenous dose of ceftolozane/tazobactam in patients with creatinine clearance ≤ 50 mL/min
| Estimated CrCL (mL/min)* | Recommended dose regimen for Zerbaxa (ceftolozane/tazobactam)** |
| 30 to 50 | 500 mg ceftolozane / 250 mg tazobactam intravenously every 8 hours |
| 15 to 29 | 250 mg ceftolozane / 125 mg tazobactam intravenously every 8 hours |
| End stage renal disease on haemodialysis | A single loading dose of 500 mg ceftolozane / 250 mg tazobactam followed after 8 hours by a 100 mg ceftolozane / 50 mg tazobactam maintenance dose administered every 8 hours for the remainder of the treatment period (on haemodialysis days, the dose should be administered at the earliest possible time following completion of haemodialysis) |
*CrCL estimated using Cockcroft-Gault formula
**All doses of Zerbaxa are administered intravenously over 1 hour and are recommended for all indications. The duration of treatment should follow the recommendations in Table 1.
Hepatic impairment
No dose adjustment is necessary in patients with hepatic impairment .
Paediatric population
The safety and efficacy of ceftolozane/tazobactam in children and adolescents below 18 years of age have not yet been established. No data are available.
Method of administration
Zerbaxa is for intravenous infusion.
The infusion time is 1 hour for 1 g / 0.5 g of Zerbaxa.
Precautions to be taken before handling or administering the product
Each vial is for single use only.
Aseptic technique must be followed in preparing the infusion solution.
Preparation of doses
The powder for concentrate for solution for infusion is reconstituted with 10 mL of water for injections or sodium chloride 9 mg/mL (0.9%) solution for injection per vial; following reconstitution the vial should be shaken gently to dissolve the powder. The final volume is approximately 11.4 mL. The resultant concentration is approximately 132 mg/mL (88 mg/mL of ceftolozane and 44 mg/mL of tazobactam).
CAUTION: THE RECONSTITUTED SOLUTION IS NOT FOR DIRECT INJECTION.
For preparation of the 1 g ceftolozane / 0.5 g tazobactam dose: Withdraw the entire contents (approximately 11.4 mL) of the reconstituted vial using a syringe and add it to an infusion bag containing 100 mL of 0.9% sodium chloride for injection (normal saline) or 5% glucose injection.
The preparations that follow relate to dose adjustments for renally impaired patients:
For preparation of the 500 mg ceftolozane / 250 mg tazobactam dose: Withdraw 5.7 mL of the contents of the reconstituted vial and add it to an infusion bag containing 100 mL of 0.9% sodium chloride for injection (normal saline) or 5% glucose injection.
For preparation of the 250 mg ceftolozane / 125 mg tazobactam dose: Withdraw 2.9 mL of the contents of the reconstituted vial and add it to an infusion bag containing 100 mL of 0.9% sodium chloride for injection (normal saline) or 5% glucose injection.
For preparation of the 100 mg ceftolozane / 50 mg tazobactam dose: Withdraw 1.2 mL of the contents of the reconstituted vial and add it to an infusion bag containing 100 mL of 0.9% sodium chloride for injection (normal saline) or 5% glucose injection.
Zerbaxa solution for infusion is clear and colourless to slightly yellow.
Variations in colour within this range do not affect the potency of the product.
Any unused medicinal product or waste material should be disposed of in accordance with local requirements.
Date of first authorisation: 18 September 2015
No significant medicinal product interactions are anticipated between ceftolozane/tazobactam and substrates, inhibitors, and inducers of cytochrome P450 enzymes (CYPs) based on in vitro and in vivo studies.
In vitro studies demonstrated that ceftolozane, tazobactam and the M1 metabolite of tazobactam did not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4 and did not induce CYP1A2, CYP2B6, or CYP3A4 at therapeutic plasma concentrations.
Ceftolozane and tazobactam were not substrates for P-gp or BCRP, and tazobactam was not a substrate for OCT2, in vitro at therapeutic plasma concentrations. In vitro data indicate that ceftolozane did not inhibit P-gp, BCRP, OATP1B1, OATP1B3, OCT1, OCT2, MRP, BSEP, OAT1, OAT3, MATE1, or MATE2-K in vitro at therapeutic plasma concentrations. In vitro data indicate that neither tazobactam nor the tazobactam metabolite M1 inhibit P-gp, BCRP, OATP1B1, OATP1B3, OCT1, OCT2, or BSEP transporters at therapeutic plasma concentrations.
Tazobactam is a substrate for OAT1 and OAT3. In vitro, tazobactam inhibited human OAT1 and OAT3 transporters with IC50 values of 118 and 147 mcg/mL, respectively. Co-administration of ceftolozane/tazobactam with OAT1 and OAT3 substrate furosemide in a clinical study did not significantly increase furosemide plasma exposures (geometric mean ratios of 0.83 and 0.87 for Cmax and AUC, respectively). However, active substances that inhibit OAT1 or OAT3 (e.g., probenecid) may increase tazobactam plasma concentrations.
