The role of melatonin has been extensively investigated in pathophysiological conditions, including autism spectrum disorder (ASD). Reduced melatonin secretion has been reported in ASD and led to many clinical trials using immediate-release and prolonged-release oral formulations of melatonin. However, melatonin’s effects in ASD and the choice of formulation type require further study. Therapeutic benefits of melatonin on sleep disorders in ASD were observed, notably on sleep latency and sleep quality. Importantly, melatonin may also have a role in improving autistic behavioral impairments. The objective of this article is to review factors influencing treatment response and possible side effects following melatonin administration. It appears that the effects of exposure to exogenous melatonin are dependent on age, sex, route and time of administration, formulation type, dose, and association with several substances (such as tobacco or contraceptive pills). In addition, no major melatonin-related adverse effect was described in typical development and ASD. In conclusion, melatonin represents currently a well-validated and tolerated treatment for sleep disorders in children and adolescents with ASD. A more thorough consideration of factors influencing melatonin pharmacokinetics could illuminate the best use of melatonin in this population. Future studies are required in ASD to explore further dose-effect relationships of melatonin on sleep problems and autistic behavioral impairments.

Background: Amoxicillin (AMX)-induced neurotoxicity is well described and may be associated with AMX overexposure. No neurotoxic concentration threshold has been determined thus far. A better knowledge of maximum tolerable AMX concentrations is of importance to improve the safety of high doses of AMX. Methods: We conducted a retrospective study using the local hospital data warehouse EhOP^® to generate a specific query related to AMX neurotoxicity symptomatology. All patient medical reports containing a mention of neurotoxicity clinical symptoms coupled with AMX plasma concentration measurements were explored. Patients were classified into two groups according to the imputability of AMX in the onset of their neurotoxicity, on the basis of chronological and semiological criteria. A receiver-operating characteristic curve was performed to identify an AMX neurotoxic steady-state concentration (Css) threshold. Results: The query identified 101 patients among 2054 patients benefiting from AMX TDM. Patients received a median daily dose of 9 g AMX, with a median creatinine clearance of 51 mL/min. A total of 17 of the 101 patients exhibited neurotoxicity attributed to AMX. The mean Css was higher for patients with neurotoxicity attributed to AMX (118 ± 62 mg/L) than those without 74 ± 48 mg/L (p = 0.002). A threshold AMX concentration of 109.7 mg/L predicted the occurrence of neurotoxicity. Conclusions: This study identified, for the first time, an AMX Css threshold of 109.7 mg/L associated with an excess risk of neurotoxicity. This approach needs to be confirmed by a prospective study with systematic neurological evaluation and TDM.

Background: The impact of pharmacokinetic variability of cabotegravir (CAB) and rilpivirine (RPV) long-acting (LA) injectable therapy on virological outcomes remains controversial. This study aimed to characterize the variability of CAB and RPV trough concentrations (Ctrough) and to identify the predictors of suboptimal exposure and virologic failure (VF) in a large real-world cohort. Methods: We conducted a multicenter observational study including people with human immunodeficiency virus type 1 (HIV-1) initiating LA-CAB/RPV as maintenance therapy from January to December 2022, in whom CAB and RPV plasma Ctrough were determined as part of therapeutic drug monitoring (TDM). Results: A total of 1674 CAB and 1687 RPV Ctrough measurements were collected from 736 people with HIV-1 (PWH). Significant interindividual variability in concentrations was observed. At month 1/month 3, 20%–30% of PWH had Ctrough <1120 ng/mL for CAB and 32 ng/mL for RPV. Predictors of lower Ctrough were body mass index (BMI) ≥30 kg/m2 and female sex at month 1, and only male sex at steady state. After a median follow-up of 12 (interquartile range, 9–16) months, VF occurred in 2.5% of PWH. At month 6 and month 12, VF was significantly associated with the presence of at least 2 risk factors (obesity, suboptimal Ctrough) (odds ratio [OR], 4.6, P = .047; OR, 5.15, P = .014), and CD4 nadir (OR, 0.56, P = .008; OR, 0.5, P = .001). Conclusions: Our large real-world study confirms significant variability in CAB and RPV exposure, with BMI and sex as key predictors of lower Ctrough. Suboptimal CAB and RPV Ctrough, particularly in people with obesity, increases the risk of VF during the first year of treatment, highlighting the usefulness of TDM in clinical practice.

Background: Cefepime-induced neurotoxicity (CIN) is commonly described but neurotoxic concentration threshold remains unclear. Method: This single-center prospective study included patients with febrile neutropenia treated by continuous infusion of cefepime in the hematology department. Both cefepime steady-state concentrations measurement (Css) and neurological assessment were performed at defined timepoints during the first 10 days after the onset of cefepime. Cefepime imputability was determined for each neurological event. The main objective was to assess the relationship between plasma cefepime exposure and the occurrence of neurotoxicity. Secondary objectives were to establish a cefepime Css threshold discriminating CIN and control group and identify influencing covariates. Results: One hundred and thirty-four patients were analyzed (346Css). CIN occurred in 9.7% of the cases (14/145 courses). Maximal Css were not significantly different between the 2 groups (53.2 ± 31.3 vs 39.5 ± 13.3 mg/L). Median neurotoxicity onset was 5 days. After multivariable analysis, both concomitant chimeric antigen receptor T-cell administration and each mg/mL increase in cefepime Css were independently associated with CIN onset (odds ratio 19.7 [5.6–69.1] and 1.030 [1.005–1.056], P < .001 and P = .020), respectively. Receiver operating characteristic curve analysis identified an adjusted threshold concentration of 36.7 mg/L (sensitivity 89%, specificity 90%) to differentiate the 2 groups. Conclusions: This study provides real-life data on CIN using a multidisciplinary approach. Cefepime exposure was found to be independently associated with the occurrence of neurotoxicity together with chimeric antigen receptor T-cell therapy. The neurotoxicity threshold of 36.7 mg/L confirms a lower toxicity threshold than for other β lactams, offering an additional tool for the management of high-dose cefepime therapy.

Staphylococcal infective endocarditis (IE) remains a hard-to-treat infection with high mortality. Both the evaluation of new innovative therapies and research on alternative models mimicking human IE are therefore urgently needed to improve the prognosis of patients with diagnosed IE. Dalbavancin is a novel anti-staphylococcal lipoglycopeptide but there are limited data supporting its efficacy on biofilm infections. This antibiotic could be an alternative to current therapies for the medical treatment of IE but it needs to be further evaluated. Here we developed an original ex vivo model of Staphylococcus aureus IE on human heart valves and assessed biofilm formation on them. After validating the model, the efficacy of two antistaphylococcal antibiotics, vancomycin and dalbavancin, was compared by measuring and visualizing their respective ability to inhibit and eradicate late-formed biofilm. Determination of the minimum biofilm inhibitory (MbIC) and eradicating (MbEC) concentrations in our ex vivo model identified dalbavancin as a promising drug with much lower MbIC and MBEC than vancomycin (respectively <0.01 versus 28 mg/L and 0.03 versus 32 mg/L). These data highlight a strong bactericidal effect of dalbavancin, particularly on an infected heart valve compared with vancomycin. Dalbavancin could be a realistic alternative treatment for the management of staphylococcal IE.