title: [Analysis of the valproic acid-meropenem interaction in hospitalised patients].
abstract: BACKGROUND
  Published data demonstrate a serious interaction between valproic acid and meropenem. However, recommendations about the management of concomitant treatment are contradictory; some experts recommend closer monitoring of valproic acid serum concentrations and others recommend avoiding concurrent therapy. The purpose of this study is to critically analyse the interaction and to evaluate the impact of pharmaceutical intervention in the use of these drugs in hospitalised patients.
  
  
  METHODS
  Study of the concomitant prescription of valproic acid and meropenem in a general hospital of 1,080 beds divided in to two periods; the first period was retrospective and observational and it was followed by a prospective period involving pharmaceutical intervention. The prescription habits between both periods were compared.
  
  
  RESULTS
  A total of 26 patients received concurrent treatment with valproic acid and meropenem (13 per period) and none of them maintained therapeutic serum levels of the antiepileptic drug. Pharmaceutical intervention modified prescription habits, reducing by half the number of days of concomitant treatment, changing the antibiotherapy and/or monitoring serum concentrations more often.
  
  
  CONCLUSIONS
  The interaction between valproic acid and meropenem is serious, especially because of the dramatic decrease in the antiepileptic serum concentrations. The concomitant use of both drugs should be avoided, replacing the antibiotherapy empirically, or according to the resistance profiles of the microorganism and maintaining the same the anti-epileptic treatment.
authors.affiliation: Servicio de Farmacia, Hospital Universitario Ramón y Cajal, Madrid, España. mvelez.hrc@salud.madrid.org
authors.forename: M
authors.initials: M
authors.lastname: Vélez Díaz-Pallarés
authors.forename: E
authors.initials: E
authors.lastname: Delgado Silveira
authors.forename: A M
authors.initials: AM
authors.lastname: Alvarez Díaz
authors.forename: C
authors.initials: C
authors.lastname: Pérez Menéndez-Conde
authors.forename: N
authors.initials: N
authors.lastname: Vicente Oliveros
authors.forename: T
authors.initials: T
authors.lastname: Bermejo Vicedo
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D000927:Anticonvulsants / Q000009:adverse effects*; D016208:Databases, Factual; D004347:Drug Interactions; D016903:Drug Monitoring; D057286:Electronic Health Records; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D000077731:Meropenem; D010595:Pharmacists; D011446:Prospective Studies; D012189:Retrospective Studies; D013845:Thienamycins / Q000009:adverse effects*; D014635:Valproic Acid / Q000009:adverse effects*
chemical_list: D000900:Anti-Bacterial Agents; D000927:Anticonvulsants; D013845:Thienamycins; D014635:Valproic Acid; D000077731:Meropenem