ObjectiveTo assess the effect of free leucine supplementation combined with resistance training versus resistance training only on muscle strength and functional status in older adults.MethodsThis was a randomized, double-blind, placebo-controlled, parallel study with two intervention groups. Thirty older adults were randomly assigned to receive either 10 g leucine/day (leucine group [LG], n=15) or a placebo (control group [CG], n=15), plus resistance training over a 12-week period. Maximal overcoming isometric leg strength, functional status, nutritional status, body composition, health-related quality of life, depression, and dietary intake were assessed at 4 and 12 weeks. Missing data at 12 weeks were handled using mixed models for repeated measurements for data imputation.ResultsTwenty-four subjects completed the 4-week assessment and eleven completed the 12-week intervention. Clinically significant gains were found in isometric leg strength at both assessment time points. Analysis of the effect size also showed how participants in LG outperformed those in CG for chair stands and the timed up and go test. No significant changes were observed for the rest of the outcomes.ConclusionOur combined analysis showed moderate changes in isometric leg muscle strength and certain components of functional status. The magnitude of changes found on these outcomes should be qualified as a positive effect of the concomitant intervention.

Carisoprodol was authorised in 1959 without a full pharmacokinetic–pharmacodynamic (PK–PD) characterisation. We designed a crossover, double-blind, placebo-controlled, randomized clinical trial to characterize the PKs of carisoprodol and its main active metabolite, meprobamate, after single (350 mg), multiple (350 mg/8 h, 14 days), and double (700 mg) doses of carisoprodol. Thirteen healthy volunteers were enrolled. After a single (350 mg) dose, the main carisoprodol parameters were (mean ± SD) Cmax: 2580 ± 1214 ng/mL, AUC0-∞: 8072 ± 6303 h x ng/mL, and half-life (T1/2): 2 ± 0.8 h. For meprobamate, the parameters were Cmax: 2181 ± 605 ng/mL and 34529 ± 7747 h x ng/mL y 9 ± 1.9 h. Different profiles were found for extensive and poor 2C19 metabolizers. After 14 days of treatment (350 mg/8 h) the results for carisoprodol were (mean ± SD) Cmax: 2504 ± 730 ng/mL, AUC0-∞: 7451 ± 3615 h x ng/mL, and T1/2: 2 ± 0.7 h. For meprobamate (a steady state was reached), the parameters were Cmax: 5758 ± 1255 ng/mL and 79699 ± 17978 h x ng/mL y 8.7 ± 1.4 h. The study allowed for the full characterization of the pharmacokinetic profile of carisoprodol and meprobamate. Accumulation of meprobamate but not of carisoprodol was evident after 14 days of treatment.