Pharmacokinetics/Pharmacodynamics and tolerability of cefiderocol in the clinical setting

Cefiderocol is a new cephalosporin with a catechol in its chemical structure faciliting its access to the interior of bacteria through iron channels. In addition, it is broadly stable to beta-lactamases. The pharmacokinetic profile is a beta-lactam one: no oral absorption, and with a wide distribution within the vascular space and the interstitial fluid of well vascularized tissues, reaching therapeutic concentrations in the alveolar lavage fluid and within the macrophage. The binding of cefiderocol to human plasma proteins, primarily albumin, is moderate (range 40-60%). The terminal elimination half-life in healthy adult subjects was 2 to 3 hours. Cefiderocol is mainly renally eliminated, so dose adjustments are recommended in subjects with moderate / severe renal impairment, in case of dialysis, and probably in patients with external clearance. Like other beta-lactams, the PK / PD parameter that has been shown to best correlate with efficacy is the efficacy time of unbound plasma concentrations (%fT>MIC), which must be close to 100% to achieve a bactericidal effect. This is possible with 2 g in a 3-hour infusion every 8 hours. In controlled trials appears to be well tolerated, similar to comparators: meropenem or imipenem-cilastatin. Cefiderocol has no apparent clinically significant effect on ECG parameters nor on plasma iron values. (AU)

Ceftobiprole: pharmacokinetics and PK/PD profile

Ceftobiprole shows many similar pharmacokinetic properties to other cephalosporins, except for not being orally bioactive, and that it is administered by IV infusion as the prodrug ceftobiprole medocaril, which is subsequently hydrolyzed in the blood into the active molecule. Distribution focus in extracellular fluid and active antibiotic concentration has been proven in different corporal tissues using dosing regimen of 500 mg intravenous infusion over 2 h every 8 h. Ceftobiprole is eliminated exclusively into the urine, thus the reason why dose adjustment is required for patients with moderate or severe renal impairment, or increased creatinine clearance. However, there is no need for dose adjustments related with other comorbidities and patients' conditions such as age, body weight. Although considering distribution features, molecular weight and dose fraction, increase dosing regimen might be necessary in patients using renal replacement therapy. The half-life of ceftobiprole is more than 3 h, allowing to easily reach optimal PK/PD parameters with the infusion time of 2 h, using the usual dosing regimen

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[Pharmacological profile of isavuconazole]. / Perfil farmacológico del isavuconazol.

Isavuconazole is a new azole, structurally related to fluconazole and voriconazole, that presents a very high oral absorption with no first-pass effect which is not interfered by the presence of food, gastric pH modifications, or mucositis. Its distribution volume is very high, probably also to cerebrospinal fluid, in spite of the fact that it circulates highly bound to plasma proteins. It is extensively metabolized through the CYP3A4 isoenzyme. Due to this reason, it is recommended to avoid co-administration with strong CYP3A4 inducers. In addition, isavuconazole may inhibit CYP3A4. Moreover, it may induce CYP2B6 and P-glycoprotein. Interestingly, this inhibitory activity seems to be lower compared to other azoles. Therefore, the management of any interaction with other medicines is easier, which is probably the most important advantage of this antifungal.

Use of non-specific intravenous human immunoglobulins in Spanish hospitals; need for a hospital protocol.

UNLABELLED: Intravenous immunoglobulin (IVIG) use in non-approved indications, the increase in consumption and its high cost recommend rationalisation in its utilisation. AIMS: To assess the use of IVIG in Spanish hospitals. METHODS: An observational, prospective and multicentre drug utilisation study was conducted in 13 tertiary Spanish hospitals. Data were collected for 3 months in patients receiving any IVIG. Patient demographics, indication for IVIG use, dosage regimen and cost of treatment were collected. RESULTS: Five hundred and fifty-four patients (mean age of 52 years) were included in the study. A total of 1,287 prescriptions were administered, and the average number of prescriptions per patient was 2.3. The mean daily dose was 24 g (range 0.6-90 g). Overall, IVIG was prescribed for authorised indications in 335 patients (60%) with 953 prescriptions (74%), for non-authorised indications with scientific evidentiary support in 86 patients (16%) with 137 prescriptions (11%), and non-authorised and non-accepted indications in 133 patients (24%) with 197 prescriptions (15%). The most frequent authorised indications were primary and secondary immunodeficiencies, and the most frequent non-authorised and non-accepted indications were multiple sclerosis and bullous dermatosis. The mean cost of IVIG per patient for authorised indications was 2,636.2 , non-authorised indications with scientific support 5,262.1 and non-accepted indications 3,555.8 . CONCLUSIONS: IVIG is prescribed for a significant number of non-authorised and non-accepted indications with a notable cost. There is an important variability in IVIG prescriptions between hospitals, indicating room for improvement in IVIG use and the need for a consensus of protocol use.

[Fosfomycin trometamol: multiple-dose regimen for the treatment of lower urinary tract infections]. / Fosfomicina trometamol. Dosis múltiples como pauta larga en el tratamiento de las infecciones urinarias bajas.

INTRODUCTION: A short antibiotic regimen is recommended for the treatment of uncomplicated lower urinary tract infection. Nevertheless, the treatment to follow in other situations is not so clearly defined. When the person affected by lower urinary tract infection is not a young woman, it is recommended to treat at least 7 days, and quinolones or cotrimoxazole are the antibiotics most often used. However, because of the frequency of drug resistance in this type if infection, it is advisable to apply antibiotics with lower rates of resistance, such as fosfomycin trometamol, for longer treatment periods than the often-used single dose. METHODS: Using the data on urinary elimination of fosfomycin after a single dose obtained in a prior study in healthy volunteers, we simulated the urinary concentrations of this antibiotic following administration of two doses. In addition, we calculated the interval of administration required to achieve urinary concentrations greater than 16 mg/L, the critical concentration of sensitivity for Escherichia coli, one of the most commonly implicated microorganisms in these infections. RESULTS: Fosfomycin concentrations in urine persisted above the defined cut-off for 161 hours after administration of two 3-g doses of fosfomycin trometamol, 72 hours apart. This implied an efficacy time of 66% in a period of 7 days. CONCLUSION: From the pharmacokinetic viewpoint, the optimum dosage of fosfomycin trometamol to achieve appropriate urinary concentrations along 7 days is administration of two 3-g doses, 72 hours apart.

Fosfomicina trometamol. Dosis múltiples como pauta larga en el tratamiento de las infecciones urinarias bajas / Fosfomycin trometamol: Multiple-dose regimen for the treatment of lower urinary tract infections

Introducción. El tratamiento de las infecciones urinarias del tracto inferior no complicadas se realiza con pautas de tratamiento cortas. En otras circunstancias no está tan clara la pauta que hay que seguir. Cuando la infección urinaria del tracto inferior no se produce en una mujer joven, la recomendación terapéutica es la utilización de antibióticos durante al menos 7 días, y son las quinolonas y el cotrimoxazol los antibióticos utilizados con mayor frecuencia. Pero debido al porcentaje de resistencias de los microorganismos implicados en este tipo de infecciones, es aconsejable evaluar otras pautas de tratamiento, de forma que habría que evaluar, entre otros, el uso de antibióticos con un menor índice de resistencias como fosfomicina trometamol, en períodos de tratamiento más largos que el uso tan extendido en dosis única. Métodos. Desde los datos de eliminación urinaria de fosfomicina obtenidos en voluntarios sanos en un estudio previo, se han simulado las concentraciones de este antibiótico en orina tras la administración de 2 dosis. Se ha calculado el intervalo más idóneo para mantener concentraciones urinarias por encima del punto de corte de Escherichia coli para fosfomicina (16 mg/l), uno de los microorganismos implicados con mayor frecuencia en este tipo de infecciones. Resultados. Las concentraciones de fosfomicina en orina se mantienen por encima del punto de corte durante 161 h cuando se administran 2 dosis de 3 g de fosfomicina trometamol separadas 72 h. Éste supone un tiempo de eficacia del 96% en un período total de 7 días. Conclusión. La pauta teórica, desde el punto de vista farmacocinético, para conseguir concentraciones de fosfomicina en orina por encima del punto de corte de E. coli es la administración de 2 dosis de 3 g de fosfomicina trometamol separadas 72 h (AU)

Introduction. A short antibiotic regimen is recommended for the treatment of uncomplicated lower urinary tract infection. Nevertheless, the treatment to follow in other situations is not so clearly defined. When the person affected by lower urinary tract infection is not a young woman, it is recommended to treat at least 7 days, and quinolones or cotrimoxazole are the antibiotics most often used. However, because of the frequency of drug resistance in this type if infection, it is advisable to apply antibiotics with lower rates of resistance, such as fosfomycin trometamol, for longer treatment periods than the often-used single dose. Methods. Using the data on urinary elimination of fosfomycin after a single dose obtained in a prior study in healthy volunteers, we simulated the urinary concentrations of this antibiotic following administration of two doses. In addition, we calculated the interval of administration required to achieve urinary concentrations greater than 16 mg/L, the critical concentration of sensitivity for Escherichia coli, one of the most commonly implicated microorganisms in these infections. Results. Fosfomycin concentrations in urine persisted above the defined cut-off for 161 hours after administration of two 3-g doses of fosfomycin trometamol, 72 hours apart. This implied an efficacy time of 66% in a period of 7 days. Conclusion. From the pharmacokinetic viewpoint, the optimum dosage of fosfomycin trometamol to achieve appropriate urinary concentrations along 7 days is administration of two 3-g doses, 72 hours apart (AU)