The long-term stability of antimicrobials dissolved in infusion solution is necessary to establish and spread the outpatient parenteral antimicrobial therapy (OPAT). In this study, we evaluated the stability of antimicrobial agents dissolved in infusion solutions. Methods: The antimicrobial agents were dissolved in infusion solutions and kept at 25 C and 31.1 C for 24 h or 4 C for 10 days in a polypropylene tube or an elastomeric infusion pump. The stability was measured by high-performance liquid chromatography. Results and conclusion: The residual ratio of cefazolin (CEZ), cefmetazole (CMZ), piperacillin (PIPC), and tazobactam (TAZ) at 31.1 C for 24 h was as follows: 95.7 AE 3.0%, 94.8 AE 0.9%, 102.6 AE 1.8%, and 103.9 AE 3.6% in saline, respectively; 94.7 AE 3.0%, 94.3 AE 1.5%, 106.1 AE 3.0%, and 107.3 AE 2.4% in 5% dextrose solution, respectively. The residual ratio of these antimicrobials at 4 C for 10 days was maintained above 90% in both saline and 5% dextrose solution. The residual ratio of all the above antimicrobials in an elastomeric infusion pump at 31.1 C for 24 h was equivalent to that in the polypropylene tube. On the other hand, doripenem and meropenem were not stable in any infusion solution at 31.1 C. CEZ, CMZ, and PIPC/TAZ dissolved in saline or 5% dextrose solution can be used in OPAT with continuous infusion pumps.

Background Linezolid causes hematological toxicity, mostly thrombocytopenia, which leads to treatment discontinuation and failure. Recent studies revealed that during linezolid therapy, the incidence of treatment-related hematological toxicity is significantly higher in patients with decreased renal function (DRF) than in those with normal renal function. Linezolid monitoring is necessary due to the high frequency of hematological toxicity in patients with DRF and the relationship between blood concentration and safety. We performed a systematic review and meta-analysis to evaluate the safety correlation between DRF and trough monitoring. Methods Articles published before June 24, 2022, on MEDLINE, Web of Sciences, Cochrane Register of Controlled Trials, and ClinicalTrials.gov were systematically analyzed. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using the Mantel–Haenszel method and the variable effects model. Results The incidence of hematological toxicity was significantly higher in patients with DRF than in those without DRF (OR = 2.37; p < 0.001). Subgroup analysis, performed according to hematotoxicity classification, including thrombocytopenia, anemia, and pancytopenia, revealed a significantly higher incidence of thrombocytopenia (OR = 2.45; p < 0.001) and anemia (OR = 2.31; p = 0.006) in patients with DRF than in those without; pancytopenia (OR = 1.41; p = 0.80) incidences were not significantly higher. Based on a systematic review, linezolid trough concentrations > 6–7 μg/mL may be associated with an increased incidence of thrombocytopenia. However, no confidential threshold values for the development of thrombocytopenia were found in the area under the concentration curve values for children or adults. Conclusion We observed a high frequency of hematological toxicity during linezolid therapy in patients with DRF. To ensure safety, linezolid trough concentrations should be ≤6–7 μg/mL.

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Objectives Raltegravir (RAL) that can form chelates with multivalent metal cations shows lateral interactions with multivalent metal cation and polycationic polymer. We investigated the interactions of RAL with multivalent metal cation preparations, Al(OH)3 and LaCO3, and polycationic polymer preparations, bixalomer (Bxl) and sevelamer (Svl). Methods Immediately before the oral administration of 40 mg/kg RAL, the rats were administered orally with the vehicle, Al(OH)3, LaCO3, Bxl, or Svl, and the time course of RAL serum concentration was followed. The in vitro binding affinity of RAL with multivalent metal cation and polycationic polymer was also evaluated using isothermal titration calorimetry (ITC). Results When Al(OH)3, LaCO3, Bxl, or Svl was concomitantly administered with RAL, the maximum concentration and area under the curve were significantly lower than those when RAL was administered alone. ITC showed the interaction of RAL with Al(OH)3 as an enthalpy‐driven reaction and its interactions with LaCO3 and Bxl as entropy–enthalpy mixed reactions. Conclusions The interaction of RAL with Al(OH)3, LaCO3, Bxl, or Svl can inhibit RAL absorption into the gastrointestinal tract, and thus, the multivalent metal cation and polycationic polymer are the modifying factors that can affect RAL pharmacokinetics.