Piperacillin sodium: antibacterial spectrum, pharmacokinetics, clinical efficacy, and adverse reactions

Physiologically Based Modeling of Cefoxitin, Cefazolin, and Piperacillin Pharmacokinetics in Obese and Lean Rats

The prevalence of obesity is rapidly increasing worldwide, however there is a notable gap in understanding how obesity affects the pharmacokinetics of drugs and how dosing should be adjusted in obese population. The goals of this work were to evaluate plasma pharmacokinetics and tissue disposition of piperacillin, cefazolin, and cefoxitin in a rat model of diet-induced obesity compared to a lean cohort. Male Long-Evans rats were fed high-fat or control diets for 23 weeks. Various measures of body size and composition were collected. The animals were administered a mixture containing 50 mg/kg cefoxitin, 50 mg/kg cefazolin, and 120 mg/kg piperacillin. Plasma and tissues were collected and analyzed using a validated LC-MS/MS method. Whole-body physiologically-based pharmacokinetic (PBPK) models were develop to capture the biodistribution of these drugs in lean and obese cohorts. Most plasma and tissue concentrations were comparable between lean and obese rats after dosing based on mg/kg of total body weight; however, in some tissues concentration was consistently higher in obese animals. PBPKs successfully captured biodistribution of three drugs and both cohorts; however, cohort-specific (lean or obese) parameters were required for liver (for cefoxitin and cefazolin) and spleen (for all three drugs) for capturing the data.The results support the necessity of using mg/kg dosing for obese rats to achieve drug exposure comparable to that of lean rats. In the future, these models could be extended to predict plasma pharmacokinetics and tissue disposition of cefoxitin, cefazolin, and piperacillin in humans by incorporating interspecies scaling approaches.

A validated LC-MS/MS method for simultaneous quantitation of piperacillin, cefazolin, and cefoxitin in rat plasma and twelve tissues

BACKGROUND

The investigation of drug disposition in tissues is critical to improving dosing strategy and maximizing treatment effectiveness, yet developing a multi-tissue bioanalytical method could be challenging due to the differences among various matrices. Herein, we developed an LC-MS/MS method tailored for the quantitation of piperacillin (PIP), cefazolin (CFZ), and cefoxitin (CFX) in rat plasma and 12 tissues, accompanied by validation data for each matrix according to the FDA and EMA guidelines.

RESULTS

The method required only a small sample volume (5 μL plasma or 50-100 μL tissue homogenates) and a relatively simple protocol for simultaneous quantitation of PIP, CFZ, and CFX within different biological matrices. Mobile phase A was composed of 5 mM ammonium formate and 0.1 % formic acid in water, while mobile phase B contained 0.1 % formic acid in acetonitrile. The mobile phase was pumped through a Synergi Fusion-RP column equipped with a guard column with a gradient elution program at a 0.3 mL/min flow rate. The mass spectrometer was operated in positive ionization mode (ESI+) using multiple reaction monitoring.

SIGNIFICANCE

The validated method has been successfully applied to quantify PIP, CFZ, and CFX from the plasma and tissue samples collected in a pilot rat study and will further be used in a large pharmacokinetic study. To our knowledge, this is also the first report presenting long-term, freeze-thaw, and autosampler stability data for PIP, CFZ, and CFX in rat plasma and multiple tissues.

Collaterally Sensitive β-Lactam Drugs as an Effective Therapy against the Pre-Existing Methicillin Resistant Staphylococcus aureus (MRSA) Biofilms

Methicillin-resistant Staphylococcus aureus (MRSA) is among the leading causes of nosocomial infections and forms biofilms, which are difficult to eradicate because of their increasing resistance to antimicrobial agents. This is especially true for pre-existing biofilms. The current study focused on evaluating the efficacy of three β-lactam drugs, meropenem, piperacillin, and tazobactam, alone and in combination against the MRSA biofilms. When used individually, none of the drugs exhibited significant antibacterial activity against MRSA in a planktonic state. At the same time, the combination of meropenem, piperacillin, and tazobactam showed a 41.7 and 41.3% reduction in planktonic bacterial cell growth, respectively. These drugs were further assessed for biofilm inhibition and removal. The combination of meropenem, piperacillin, and tazobactam caused 44.3% biofilm inhibition, while the rest of the combinations did not show any significant effects. Results also revealed that piperacillin and tazobactam exhibited the best synergy against the pre-formed biofilm of MRSA, with 46% removal. However, adding meropenem to the piperacillin and tazobactam combination showed a slightly reduced activity towards the pre-formed biofilm of MRSA and removed 38.7% of it. Although the mechanism of synergism is not fully understood, our findings suggest that these three β-lactam drugs can be used in combination as very effective therapeutic agents for the treatment of pre-existing MRSA biofilms. The in vivo experiments on the antibiofilm activity of these drugs will pave the way for applying such synergistic combinations to clinics.

Piperacillin/tazobactam-induced paresthesiae

OBJECTIVE

To describe a case of a delayed-type hypersensitivity (DTH) reaction to piperacillin/tazobactam in which painful paresthesiae were a predominant feature.

CASE SUMMARY

A 27-year-old man with a history of intravenous drug abuse was admitted for treatment of a pulmonary parenchymal abscess in the setting of lower-limb deep-venous thrombosis and methicillin-sensitive Staphylococcus aureus bacteremia. He was treated with intravenous piperacillin/tazobactam 4.5 g 3 times daily; however, after 2 weeks of therapy, he developed symptoms (eg, fever, chills) and laboratory abnormalities (eg, white blood cell count 2.1 x 10(3)/mm3, erythrocyte sedimentation rate 63 mm/h) suggestive of a DTH reaction. This was accompanied by infusion-related painful paresthesiae. The symptoms and laboratory abnormalities resolved within 48 hours of treatment being switched to flucloxacillin.

DISCUSSION

Due to the close temporal association and the absence of any other obvious explanation, we believe these paresthesiae represent an additional feature of the DTH reaction to piperacillin/tazobactam in this patient. Use of the Naranjo probability scale indicated a probable relationship between the paresthesiae and administration of piperacillin/tazobactam.

CONCLUSIONS

To our knowledge, as of March 24, 2006, this is the first case in which a DTH reaction to piperacillin/tazobactam manifesting as fever, neutropenia, and thrombocytopenia has been associated with paresthesiae.

Randomized Comparison of Piperacillin/Tazobactam Versus Imipenem/Cilastatin in the Treatment of Patients with Intra-abdominal Infection

OBJECTIVES

Treatment of intra-abdominal infections remains a challenge because of their polymicrobial nature and associated mortality risk. Broad-spectrum empiric coverage is usually required. This randomized study compared the efficacy and safety of intravenous piperacillin/tazobactam with those of intravenous imipenem/cilastatin in the treatment of 293 hospitalized patients with intra-abdominal infection.

METHODS

A total of 149 patients received piperacillin/tazobactam 4 g/500 mg every 8 hours, and 144 patients received imipenem/cilastatin 500 mg/500 mg every 6 hours. Efficacy was evaluated by clinical and bacteriological response. Safety was evaluated by analysis of adverse events and physical and laboratory examinations.

RESULTS

Clinical and bacteriological responses in both evaluable treatment groups were equivalent. The clinical success was 97% (108/111) for piperacillin/tazobactam and 97% (100/103) for imipenem/cilastatin. Bacteriological success was 97% (67/69) for piperacillin/tazobactam and 95% (61/64) for imipenem/cilastatin. The most common pathogens were Escherichia coli, Klebsiella pneumoniae, Enterobacter species and Pseudomonas aeruginosa. The frequencies of treatment-related adverse events were similar (16 with piperacillin/tazobactam and 19 with imipenem/cilastatin).

CONCLUSIONS

These results suggest that the safety and efficacy of piperacillin/tazobactam administered every 8 hours are equivalent to those of imipenem/cilastatin administered every 6 hours for the treatment of intra-abdominal infections.

Choleresis and inhibition of biliary lipid secretion induced by piperacillin in the rat

1. The effects of the administration piperacillin on bile flow and biliary lipid secretion were studied in male Wistar rats. 2. Intravenous injection of piperacillin at doses ranging from 0.3 to 3.0 mmol/kg bodyweight led to an increase in its biliary concentration and excretion rate. Maximal biliary excretion was reached at a dose of 2.0 mmol/kg piperacillin. 3. Excretion of the antibiotic into bile was associated with a marked choleresis. A linear relationship was observed between bile flow and piperacillin excretion, 5.7 micro L bile being produced per micro mol piperacillin excreted into the bile. 4. Continuous i.v. infusion of piperacillin at 2.0 mmol/100 g per min did not result in significant changes in bile acid or cholesterol secretion, but biliary phospholipid secretion was markedly reduced. The inhibitory effect on phospholipid secretion was also present when biliary lipid output had been previously increased by an infusion of taurocholate (200 nmol/100 g per min). Addition of taurocholate did not reverse the impairment of phospholipid secretion induced by piperacillin. 5. These results indicate that acute administration of piperacillin in the rat induces a marked choleresis by stimulating bile acid-independent bile flow. The significant impairment in phospholipid secretion suggests a specific effect on intracellular supply and/or translocation across the canalicular membrane.

Treatment of nosocomial postoperative pneumonia in cancer patients: a prospective randomized study

BACKGROUND

Nosocomial pneumonia continues to be associated with high morbidity and mortality in cancer patients.

METHODS

In an attempt to find an optimal treatment for this infection, nonneutropenic cancer patients with postoperative nosocomial pneumonia were randomized to receive either piperacillin/tazobactam (P/T) 4.5 g i.v. every 6 hours (30 patients) or clindamycin (Cl) 900 mg plus aztreonam (Az) 2 g i.v. every 8 hours (22 patients). Amikacin 500 mg i.v. every 12 hours was given to all patients for the first 48 hours.

RESULTS

The two groups were comparable for the characteristics of pneumonia that included gram-negative etiology and duration of intubation. Response rates were 83% for patients who received P/T and 86% for those who received Cl/Az (P > .99). There were no serious adverse events; however, at our center the cost of the P/T regimen was $73.86 compared with $99.15 for the Cl/Az regimen.

CONCLUSIONS

The two regimens had comparable high efficacy, and P/T had a slight cost advantage. Either of these antibiotic regimens combined with an aminoglycoside could lead to favorable outcome in cancer patients at high risk for nosocomial pneumonia.

Determination of free extracellular concentrations of piperacillin by microdialysis

The tissue penetration and distribution of antibiotics is of great importance, since most of the infections occur in the tissue. At the infection site, the free, unbound fraction of the antibiotic is responsible for the antiinfective effect. These free extracellular concentrations can be measured by microdialysis. It was the aim of the study to correlate free levels of the beta-lactam antibiotic piperacillin in blood with those in tissue. In vivo microdialysis sampling was used to study the tissue distribution patterns of piperacillin in anesthetized rats after single dose iv administration of the drug. The pharmacokinetics of piperacillin in plasma were consistent with a two-compartment body model. Comparisons between calculated free concentrations in the peripheral compartment and measured free extracellular concentrations revealed excellent agreement. Microdialysis is a suitable method to evaluate unbound drug concentrations in the tissues. In case of piperacillin, predictions of the concentration time profiles of free drug in the peripheral compartment can be made on the basis of plasma data.

The treatment of severe intra-abdominal infections: the role of piperacillin/tazobactam

Intra-abdominal infections require treatment effective against both aerobic and anaerobic bacteria. Piperacillin/tazobactam, a beta-lactam/beta-lactamase-inhibitor combination, has a spectrum that includes Gram-positive and Gram-negative aerobic and anaerobic organisms. In one comparative study of piperacillin/tazobactam and gentamicin/clindamycin, 88% of patients treated with piperacillin/tazobactam had a favorable clinical outcome at endpoint compared to 74% of patients treated with gentamicin plus clindamycin. Bacteriological response at endpoint was 87% in the piperacillin/tazobactam group and 74% in the gentamicin plus clindamycin group. In a comparative trial of piperacillin/tazobactam versus imipenem/cilastatin, the clinical cure rate was 91% in the piperacillin/tazobactam group and 69% in the imipenem/cilastatin group (p = 0.005). Among microbiologically evaluable patients, the infecting organism was eradicated in 93% of piperacillin/tazobactam-treated patients compared to 76% eradication among imipenem/cilastatin-treated patients (p = 0.029). Results of these clinical trials and others have shown that piperacillin/tazobactam is a safe and effective alternative to either combination or monotherapy for intra-abdominal infections.

Pharmacokinetic characteristics of piperacillin/tazobactam

Piperacillin/tazobactam is a new combination of a broad-spectrum penicillin and a beta-lactamase inhibitor. In studies in healthy volunteers, the pharmacokinetics of piperacillin combined with tazobactam were similar to those of piperacillin alone. In contrast, tazobactam administered with piperacillin achieved higher plasma concentrations and had a longer half-life than tazobactam administered alone. Intravenous infusion of 4.0 g piperacillin with 0.5 g tazobactam over 5 min resulted in mean maximum plasma concentrations of 380 micrograms piperacillin/ml and 35.3 micrograms tazobactam/ml; half-lives were 1.14 h for piperacillin and 0.92 h for tazobactam. Within 30 min of infusion, piperacillin/tazobactam achieves 16-85% of plasma concentrations in skin, muscle, lung, gallbladder, and intestinal mucosa. Plasma and tissue levels remain above the MIC90s of major pathogens for 2 h post administration. These findings show that piperacillin/tazobactam is truly synergistic combination which can be expected to be effective in treating a wide variety of infections in the clinical setting.

Piperacillin/tazobactam in complicated urinary tract infections

Piperacillin/tazobactam, at a dosage of 4 g/500 mg every 8 h, was administered intravenously to 217 patients with complicated urinary tract infections. The most common diagnosis was pyelonephritis. The most common pathogen was Escherichia coli (47%) followed by Pseudomonas aeruginosa (13%), and enterococci (8%). Among clinically evaluable patients, 86% (115/134) were cured or improved at the study endpoint and 14% (19/134) were clinical failures or relapsed. Among bacteriologically evaluable patients, 85% (95/112) had a favorable clinical response at endpoint. The bacteriological response rate was 73% (82/112) at endpoint. Overall, 82% of all pathogens were eradicated. Therapy was associated with a low incidence of side effects, and adverse experience were mild and of short duration.

Penetration of piperacillin-tazobactam into cancellous and cortical bone tissues

The penetration characteristics of piperacillin-tazobactam into cortical and cancellous bone tissues were investigated in 10 patients undergoing total hip replacement. The concentration ratios of piperacillin/tazobactam were 9.4 +/- 1.8 in cancellous bone tissue and 8.0 +/- 2.2 in cortical bone tissue, which were close to the 8:1 ratio of drugs administered. The mean ratios of drug concentrations in bone and plasma for cancellous and cortical tissue were 23 and 18%, respectively, for piperacillin and 26 and 22%, respectively, for tazobactam. The concentrations of tazobactam achieved are sufficient to exert anti-beta-lactamase activity and supportive of clinical trials involving bone and joint infections, including those caused by beta-lactamase-producing pathogens.

Treatment of hospitalized patients with complicated skin and skin structure infections: double-blind, randomized, multicenter study of piperacillin-tazobactam versus ticarcillin-clavulanate. The Piperacillin/Tazobactam Skin and Skin Structure Study Group

We compared the efficacy and safety of two beta-lactam-beta-lactamase inhibitor combinations, namely, piperacillin-tazobactam and ticarcillin-clavulanate, in the treatment of complicated bacterial infections of skin that required hospitalization. The study was a randomized, double-blind, comparative trial involving 20 centers. The infections were classified as (i) cellulitis with drainage, (ii) cutaneous abscess, (iii) diabetic or ischemic foot infection, and (iv) infected wounds and ulcers with drainage. The clinical response rates were comparable for the two treatment regimens (61% of the patients were cured with piperacillin-tazobactam and ticarcillin-clavulanate and improvement was seen in 15 and 16% of patients treated with piperacillin-tazobactam and ticarcillin-clavulanate, respectively). Both regimens were found to be safe and well tolerated. These data support the use of piperacillin-tazobactam for initial empiric therapy of hospitalized patients with complicated skin and skin structure infections.

Piperacillin-tazobactam versus imipenem-cilastatin for treatment of intra-abdominal infections

In order to compare the clinical and microbiological efficacies and safety of piperacillin plus tazobactam with those of imipenem plus cilastatin, 134 patients with intra-abdominal infections (73 patients with appendicitis) participated in an open randomized comparative multicenter trial. A total of 40 men and 29 women (mean age, 53 years; age range, 18 to 92 years) were enrolled in the piperacillin-tazobactam group and 40 men and 25 women (mean age, 54 years; age range, 16 to 91 years) were enrolled in the imipenem-cilastatin group. The patients received either piperacillin (4 g) and tazobactam (500 mg) every 8 h or imipenem and cilastatin (500 mg each) every 8 h. Both regimens were given by intravenous infusion. A total of 113 patients were clinically evaluable. Of 55 patients who received piperacillin-tazobactam, 50 were clinically cured, while 40 of 58 patients in the imipenem-cilastatin group were clinically cured. The differences were significant (Wilcoxon test; P = 0.005). There were 4 failures or relapses in the piperacillin-tazobactam group and 18 failures or relapses in the imipenem-cilastatin group. The microorganisms isolated were eradicated in similar proportions in the two patient groups. Adverse reactions, mainly gastrointestinal disturbances and nausea, were noted in 13 patients who received piperacillin-tazobactam and in 14 patients who received imipenem-cilastatin. Results of the present study show that piperacillin-tazobactam is effective and safe for the treatment of intra-abdominal infections.

Effect of piperacillin/tazobactam therapy on intestinal microflora

The effect of piperacillin/tazobactam treatment upon the intestinal microflora was studied in 20 patients with intraabdominal infections. The patients received piperacillin 4 g combined with tazobactam 500 mg q 8 h by intravenous injection for 4-8 days. Stool specimens were collected before, during and after therapy for cultivation of aerobic and anaerobic microorganisms. Six patients had measurable concentrations of piperacillin (1.2-276 mg/kg/faeces) and 4 patients tazobactam concentrations (0.8-22.2 mg/kg/faeces) in the faecal specimens during therapy. The number of enterobacteria and enterococci slightly decreased while there were no changes in the number of staphylococci and bacilli. The anaerobic microflora was also slightly affected. There was a minor decrease in the number of bifidobacteria, eubacteria, lactobacilli, clostridia and veillonella but the numbers of anaerobic Gram-positive cocci and bacteroides were not influenced by the treatment. After therapy, the aerobic and anaerobic microflora returned to normal levels in all patients. None of the patients had Clostridium difficile or cytotoxin in the stools or developed diarrhoea.

Randomized trial using piperacillin versus ampicillin and amikacin for treatment of premature neonates with risk factors for sepsis

Premature infants with risk factors for early onset sepsis who were less than seven days of age were blindly randomized to receive either piperacillin and placebo (200 infants) or ampicillin and amikacin (196 infants). One of 30 treated infants developed positive blood cultures. The overall mortality in the two groups was 8.5% for piperacillin/placebo and 13.8% for ampicillin/amikacin (p = 0.11). Serum creatinine elevation above 100 mumol/l (1.131 mg/dl) during treatment was similar in the two groups. The effectiveness of piperacillin/placebo is similar to that of ampicillin/amikacin for empiric treatment of premature newborns with risk factors for early onset sepsis.

Hemorrhagic complications of piperacillin therapy

Clinically significant hemorrhage associated with extended spectrum anti-Pseudomonas penicillins is uncommon. We describe 2 patients with bleeding complications owing to piperacillin. In addition, we review the incidence and mechanism of this adverse reaction, and make suggestions for the management of these patients.

Therapeutic decision-making: a model for formulary evaluation

A systematic approach of evaluating medications for a hospital formulary is discussed. The hospital formulary is a program of objective evaluation, selection, and use of medicinal agents in the hospital. In light of the ever-increasing numbers of new and/or improved therapeutic agents, formulary decisions must be made with an eye to the future. Therefore, it appears that the best means of choosing a medication for formulary addition, both clinically and economically, is to choose an agent based on its clinical indication(s). Examples of such indications are presented. Selecting formulary agents by indication rather than by simple drug cost or pharmacologic class should ensure the most effective utilization of therapeutic agents and hopefully a diminution of overall costs.

Prolonged elimination of piperacillin in a patient with renal and liver failure

A 22-year-old female with acute leukemia was admitted to the oncology center for evaluation and treatment. Piperacillin was used during her admission for treatment of Pseudomonal sepsis. The patient's renal and liver function deteriorated during the hospital course, requiring large dose adjustments of piperacillin. The elimination half-life of piperacillin was estimated to be 32 hours. Patients with both liver and renal disease require only small doses of piperacillin to achieve therapeutic plasma concentration.