New Predictive Equation for the Estimation of Plasma Concentrations of Formed Colistin in Patients Treated with Colistimethate Sodium for Multidrug-Resistant Gram-Negative Bacterial Infections.

BACKGROUND: The clinical use of colistin methanesulphonate (CMS) is limited by potential nephrotoxicity. The selection of an efficient and safe CMS dose for individual patients is complicated by the narrow therapeutic window and high interpatient pharmacokinetic variability. In this study, a simple predictive equation for estimating the plasma concentration of formed colistin in patients with multidrug and extremely drug-resistant gram-negative bacterial infections was developed. METHODS: The equation was derived from the largest clinical cohort of patients undergoing therapeutic drug monitoring (TDM) of colistin for over 8 years in a tertiary Spanish hospital. All variables associated with Css,avg were selected in a multiple linear regression model that was validated in a second cohort of 40 patients. Measured Css,avg values were compared with those predicted by our model and a previous published algorithm for critically ill patients. RESULTS: In total, 276 patients were enrolled [the mean age was 67.2 (13.7) years, 203 (73.6%)] were male, and the mean (SD) Css,avg was 1.12 (0.98) mg/L. Age, gender, estimated glomerular filtration rate, CMS dose and frequency, and concomitant drugs were included in the model. In the external validation, the previous algorithm appeared to yield more optimized colistin plasma concentrations when all types of Css,avg values (high and low) were considered, while our equation yielded a more optimized prediction in the subgroup of patients with low colistin plasma concentrations (Css,avg <1.5 mg/L). CONCLUSIONS: The proposed equation may help clinicians to better use CMS among a wide variety of patients, to maximize efficacy and prevent nephrotoxicity. A further prospective PK study is warranted to externally validate this algorithm.

Outcomes of Drug Interactions Between Antiretrovirals and Co-Medications, Including Over-the-Counter Drugs: A Real-World Study.

INTRODUCTION: The objective was to characterize real-world outcomes of drug-drug interactions (DDIs) between antiretrovirals (ARVs) and other drugs, including over-the-counter medications (OTC), and treatment outcomes in clinical practice. METHODS: www.clinicalcasesDDIs.com is an open-access website for healthcare providers to consult and briefly describe real-world clinical cases on DDI with ARVs. We reviewed all the clinical cases reported to the website between March 2019 and May 2023. RESULTS: A total of 139 cases were reported, mostly involving ritonavir or cobicistat (boosters; 74 cases), unboosted integrase inhibitors (InSTI; 29 cases), and non-nucleoside reverse transcriptase inhibitors (NNRTI; 23 cases). Central nervous system drugs (29 cases) and cardiovascular drugs (19 cases) were the most frequently described co-medications. Notably, OTC medications were implicated in 27 cases, including mineral supplements (11 cases), herbals (8 cases), weight loss drugs (4 cases), anabolic steroids (3 cases), and recreational drugs (1 case). OTC acted as the perpetrator drug in 21 cases, leading to loss of ARV efficacy in 17 instances (mineral supplements in 10 cases, weight loss drugs in 4 cases, herbals in 3 cases). Additionally, toxicity was reported in 4 out of 6 cases where OTC was considered the victim drug of the DDI (anabolic steroids in 3 cases, MDMA in 1 case). CONCLUSIONS: Frequent unwanted outcomes resulting from DDIs between ARVs and OTC medications underscore the importance of integrating non-prescription drugs into medication reconciliation. The real-world data available through www.clinicalcasesDDIs.com serves as a valuable resource for assessing the clinical relevance of DDIs.

Complementary and alternative medicine in HIV care: frequency of consumption, risks and interactions with antiretroviral therapy.

OBJECTIVES: People living with HIV (PLWH) are common users of complementary and alternative medicine (CAM). The main objective of this study was to study the frequency and patterns of CAM natural products use in a large cohort of PLWH and to identify potential drug-drug interactions (DDIs) and the impact on their antiretroviral treatment (ART) adherence and efficacy. METHODS: This was a cross-sectional multicenter survey including 420 PLWH from different Spanish hospitals. Participants completed a face-to-face questionnaire on CAM consumption and different sociodemographic and clinical data were collected. DDIs between CAM and ART were identified and classified according to the Liverpool University Database and patient factors related to CAM consumption were assessed. RESULTS: 420 participants were included (82.6% male, mean age 47 years); 209 patients (49.8%) were taking at least one CAM. The most consumed CAM were green, black and red tea (n=146, 25.4%), ginger (n=26, 4.5%), fish oil (n=25, 4.4%) and cannabis (n=24, 4.2%). An ART based on integrase inhibitors was the only factor independently associated with CAM consumption (OR 1.54, 95% CI 1.04 to 2.26). 50 potential CAM-ART interactions in 43 (20.6%) patients taking CAM were identified, being clinically significant in 80% of the cases. CAM products most frequently involved with a potential significant DDI were supplements containing divalent cations (n=11) and garlic (n=7). No differences in ART efficacy and adherence were observed between patients with and without CAM consumption. CONCLUSIONS: Almost 50% of patients were taking at least one CAM product and its use was associated with an integrase inhibitor based ART. One out of every six patients was at risk of presenting with an interaction between a CAM and their ART, confirming the need to review continuously the use of CAM as part of the medication review process.

Stability Studies of Antipseudomonal Beta Lactam Agents for Outpatient Therapy.

Outpatient parenteral antimicrobial therapy (OPAT) is a useful treatment strategy against Pseudomonas aeruginosa and other multidrug-resistant bacteria. However, it is hindered by the lack of stability data for the administration of antibiotics under OPAT conditions. Our objective was to investigate the stability of nine antipseudomonal and broad-spectrum beta lactam antibiotics (aztreonam, cefepime, cefiderocol, ceftazidime, ceftazidime/avibactam, ceftolozane/tazobactam, meropenem, meropenem/vaborbactam, and piperacillin/tazobactam) to allow the spread of OPAT programs. All the antibiotics were diluted in 500 mL 0.9% sodium chloride and stored at 4, 25, 32, and 37 °C for 72 h in two different devices (infusion bags and elastomeric pumps). The solutions were considered stable if the color, clearness, and pH remained unchanged and if the percentage of intact drug was ≥90%. All the antimicrobials remained stable 72 h under refrigerated conditions and at least 30 h at 25 °C. At 32 °C, all the antibiotics except for meropenem and meropenem/vaborbactam remained stable for 24 h or more. At 37 °C, only aztreonam, piperacillin/tazobactam, cefepime, cefiderocol, and ceftolozane/tazobactam were stable for at least 24 h. The stability results were the same in the two devices tested. All the antibiotics studied are actual alternatives for the treatment of antipseudomonal or multidrug-resistant infections in OPAT programs, although the temperature of the devices is crucial to ensure antibiotic stability.

Diagnóstico diferencial de psicosis de inicio a los 64 años con síntomas de tipo esquizofrenia / Differential diagnosis of psychosis with schizophrenia-like symptoms beginning at age 64

Introducción: Desde los inicios de la psiquiatría, la psicosis de comienzo por encima de los 60 años de edad ha suscitado diversas controversias diagnósticas. Uno de los objetos de mayor discusión ha sido la validez de la aplicación del diagnóstico de esquizofrenia en esta franja de edad. Actualmente existen consensos científicos sobre el diagnóstico, la nomenclatura y el tratamiento de la esquizofrenia de inicio tardío y la psicosis de inicio muy tardío tipo esquizofrenia. Método: Reporte de caso. Resultado: Se presenta el caso de una mujer, quien con 64 años de edad presentó ideas delirantes y alucinaciones. Una vez realizado el diagnóstico diferencial con delírium y otros trastornos somáticos, demencia y trastorno delirante fue diagnosticada con psicosis tipo esquizofrenia de inicio muy tardío. Discusión y conclusión: Se discute la validez e historia del concepto de esquizofrenia de inicio tardío, sus principales diagnósticos diferenciales y características clínicas...