This study aimed to clarify the efficacy, safety, and pharmacokinetics of piperacillin-tazobactam (PIPC-TAZ) in late elderly Japanese patients. This is the first antimicrobial pilot study in late elderly patients with nursing and healthcare associated pneumonia. After PIPC-TAZ administration, PIPC concentrations in plasma were measured chromatographically and the pharmacokinetic parameters were estimated. Efficacy, safety, and bacteriological evaluations were also carried out. The mean age was 85.0 years old and most of the patients were late elderly. Chest X-rays, body temperature, white blood cell count, and C reactive protein all improved significantly, and a high efficacy ratio of 90.9% was observed. Serious nephrotoxicity was observed in 4 cases (18.2%) after administration of PIPC-TAZ. Creatinine clearance (mean S.D.) measured before PIPC-TAZ therapy was significantly lower in the nephrotoxicity group (32.5 4.4 mL/min) than in the non-nephrotoxicity group (46.1 16.7 mL/min), although the ages were not different between the 2 groups. In the pharmacokinetic parameters for PIPC, total clearance was slightly lower in the nephrotoxicity group than in the non-nephrotoxicity group. However, no significant difference was observed in plasma PIPC levels between the 2 groups. In patients with renal impairment, especially with a creatinine clearance of <40 mL/ min, renal impairment was found to be an influencing factor for severe nephrotoxicity following PIPC-TAZ administration. In conclusion, the results suggest that physicians should pay close attention in order to avoid possible toxicity, and that deliberate administration planning and careful follow-up are required in late elderly patients with comprised organ dysfunction.
The aim of this study was to develop a population pharmacokinetic model for piperacillin (PIPC)/tazobactam (TAZ) in late elderly patients with pneumonia and to optimize the administration planning by applying pharmacokinetic/pharmacodynamic (PK/PD) criteria. PIPC/TAZ (total dose of 2.25 or 4.5 g) was infused intravenously three times daily to Japanese patients over 75 years old. The plasma concentrations of PIPC and TAZ were determined using high-performance liquid chromatography and modeled using the NONMEM program. PK/PD analysis with a random simulation was conducted using the final population PK model to estimate the probability of target attainment (PTA) profiles for various PIPC/TAZ-regimen-minimum-inhibitory-concentration (MIC) combinations. The PTAs for PIPC and TAZ were determined as the fraction that achieved at least 50% free time > MIC and area under the free-plasma-concentration-time curve over 24 h ≥ 96 µg h/mL, respectively. A total of 18 cases, the mean age of which was 86.5 ± 6.0 (75-101) years, were investigated. The plasma-concentration-time profiles of PIPC and TAZ were characterized by a two-compartment model. The parameter estimates for the final model, namely the total clearance, central distribution volume, peripheral distribution volume, and intercompartmental clearance, were 4.58 + 0.061 × (CL cr − 37.4) L/h, 5.39 L, 6.96 L, and 20.7 L/h for PIPC, and 5.00 + 0.059 × (CL cr − 37.4) L/h, 6.29 L, 7.73 L, and 24.0 L/h for TAZ, respectively, where CL cr is the creatinine clearance. PK/PD analysis using the final model showed that in drug-resistant strains with a MIC > 8 µg/mL, 4.5 g of PIPC/TAZ every 6 h was required, even for the patients with a CL cr of 50-60 mL/min. The population PK model developed in this study, together with MIC value, can be useful for optimizing the PIPC/TAZ dosage in the over-75-year-old patients, when they are administered PIPC/TAZ. Therefore, the findings of present study may contribute to improving the efficacy and safety of the administration of PIPC/TAZ therapy in late elderly patients with pneumonia.
Abstract. An association between UDP glucuronosyltransferase 1 family, polypeptide A1 (UGT1A1) polymorphisms and irinotecan-induced neutropenia has been previously reported. In this study, we assessed the clinical usefulness of testing for UGT1A1 polymorphisms prior to the initiation of irinotecan-based chemotherapy, as this remains a controversial subject. A total of 136 lung cancer patients who were treated with a combination of nedaplatin and irinotecan as initial chemotherapy were assessed. Following exclusion of patients exhibiting low UGT1A1 enzyme activity, 70 patients were treated after UGT1A1 polymorphism testing (test group) and 66 patients were treated without UGT1A1 polymorphism testing (non-test group). We retrospectively analyzed and compared the adverse events between the test and the non-test groups and observed no reduction in hematological or non-hematological toxicities in the test group compared to that in the non-test group. Of the 9 patients with grade 4 or 5 non-hematological toxicity, 6 patients had febrile neutropenia (FN). All the patients with FN were aged >70 years. The incidence of adverse events was significantly higher among patients aged >70 years compared to that among younger patients. In conclusion, in patients treated with nedaplatin and irinotecan combination chemotherapy, UGT1A1 polymorphism testing prior to the initiation of chemotherapy did not reduce the incidence of adverse events. Therefore, UGT1A1 polymorphism testing alone may not be sufficient to predict the occurrence of severe adverse events and it may be more important to effectively manage adverse events, particularly in elderly patients.
Elderly asthmatics treated by GPs underestimated the severity of their asthma and asthmatics seen by GPs were undertreated. The results stress the need to engage patients in educational activities, to adhere to guidelines, and to improve the coordination between GP and RS.
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