and efficacy as other antibiotic combinations such as ceftazidime with the aminoglycoside tobramycin in the treatment of patients with hospital acquired pneumonia. In a clinical comparison primarily targeting patients not initially placed in intensive care units, piperacillin-tazobactam was found to produce higher clinical and microbiological rates of success. By contrast, the drug efficacy of ceftazidime and piperacillin-tazobactam resulted in similar response rates (61.5% and 63.9 respectively) when tobramycin was added into both groups. Identical evaluations are shown when compared to the imipenem and tobramycin combination, where the administration of piperacillin-tazobactam on patients (especially those under mechanical ventilation) was only consisted of a slightly higher response rate. Administration Piperacillin is not absorbed orally, and must therefore be given by intravenous or intramuscular injection. It has been shown that the bactericidal actions of the drug do not increase with concentrations of piperacillin higher than 4-6 x MIC, which means that the drug is concentration-independent in terms of its actions. Piperacillin has instead shown to offer higher bactericidal activity when its concentration remains above the MIC for longer periods of time (50% time>MIC showing the highest activity). This higher activity present in continuous dosing has not been directly linked to clinical outcomes, but however does show promise of lowering possibility of resistance and decreasing mortality. Extending the time of piperacillin-tazobactam infusion allows the drugs to maintain the necessary concentrations needed within the body to prevent bacterial growth, enhancing bactericidal activity. The studies supporting this theory generally administered ~3.375g of piperacillin-tazobactam every 8 hours during a 4-hour infusion, while for organisms with higher minimum inhibitory concentrations, ~4.5g of piperacillin-tazobactam was administered every 6 hours during a 3-hour infusion. The recommended doses provided by the BNFC for infants with hospital-acquired infections are 90 mg/kg every 8 hours for infants, a maximum of 4.5g every 6 hours for children, and 4.5g every 8 hours for children aged 12 and above. A dosage of 90 mg/kg every 6 hours is suggested for infants and children diagnosed with neutropenia. Adverse effects Common side effects associated with the administration of piperacillin-tazobactam include: Gastrointestinal: constipation, diarrhea, nausea, vomiting Dermatologic: erythema, pain, phlebitis, rash Neurologic: headaches, insomnia Prolonged periods of piperacillin-tazobactam therapy have been associated with the potential development of hematologic adversities such as leukopenia (16.3%), neutropenia (10%), and eosinophilia (10%) in adult patients. The combination of piperacillin-tazobactam with other antibiotics was found to be a major risk factor for leukopenia