Martín-Hernández, ElenaQuijada-Fraile, PilarCorrecher, PatriciaMeavilla, SilviaSánchez-Pintos, Paulade Las Heras Montero, JavierBlasco-Alonso, JavierDougherty, LucyMarquez, AnaPeña-Quintana, LuisCañedo, ElviraGarcía-Jimenez, María ConcepciónMoreno Lozano, Pedro JuanMurray Hurtado, MercedesCamprodon Gómez, MaríaBarrio-Carreras, Deliade Los Santos, MarielaDel Toro, MireiaCouce, María LVitoria Miñana, IsidroMorales Conejo, MontserratBellusci, Marcello2023-05-032023-05-032022-08-282077-0383http://hdl.handle.net/10668/21339Background and objectives: Glycerol phenylbutyrate (GPB) has demonstrated safety and efficacy in patients with urea cycle disorders (UCDs) by means of its clinical trial program, but there are limited data in clinical practice. In order to analyze the efficacy and safety of GPB in clinical practice, here we present a national Spanish experience after direct switching from another nitrogen scavenger to GPB. Methods: This observational, retrospective, multicenter study was performed in 48 UCD patients (age 11.7 ± 8.2 years) switching to GPB in 13 centers from nine Spanish regions. Clinical, biochemical, and nutritional data were collected at three different times: prior to GPB introduction, at first follow-up assessment, and after one year of GPB treatment. Number of related adverse effects and hyperammonemic crisis 12 months before and after GPB introduction were recorded. Results: GPB was administered at a 247.8 ± 102.1 mg/kg/day dose, compared to 262.6 ± 126.1 mg/kg/day of previous scavenger (46/48 Na-phenylbutyrate). At first follow-up (79 ± 59 days), a statistically significant reduction in ammonia (from 40.2 ± 17.3 to 32.6 ± 13.9 μmol/L, penAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/clinical practiceglycerol phenylbutyrate (GPB)sodium benzoate (NaBZ)sodium phenylbutyrate (NaPB)urea cycle disorders (UCDs)Switching to Glycerol Phenylbutyrate in 48 Patients with Urea Cycle Disorders: Clinical Experience in Spain.research article36078975open access10.3390/jcm11175045PMC9457033https://www.mdpi.com/2077-0383/11/17/5045/pdf?version=1661738889https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9457033/pdf