Effect of a combination of duloxetine with hydroxyzine on experimental models of anxiety in mice

OBJECTIVE: There is a strong association between depression and anxiety. Duloxetine, an antidepressant agent, is also used in the treatment of anxiety. Hydroxyzine is preferred over benzodiazepines in the treatment of anxiety. Present study was designed to study the impact of a combination of duloxetine with hydroxyzine in treatment of anxiety. MATERIALS AND METHODS: Mice received intraperitoneal injection of normal saline (10 ml/kg), duloxetine alone (10 mg/kg), hydroxyzine alone (10 mg/kg), and hydroxyzine plus duloxetine (5 mg/kg, each). RESULTS: The in vivo results (elevated plus maze and light/dark transition tests) showed significant anxiolytic activity with the hydroxyzine treatment than the control group. The brain monoamines were significantly increased in hippocampi, cerebral cortices, and whole brain in drug-treated groups than in the control group. The group receiving the combination showed similar results in the in vivo models and in vitro tests (brain monoamine estimations) than respective monotherapies, with the exception of a greater increase of norepinephrine levels in cerebral cortices in duloxetine-treated group. CONCLUSION: Combination of duloxetine with hydroxyzine is not beneficial in anxiolytic treatment than the respective monotherapies. There is a need to study the pharmacokinetic drug-drug interactions to understand the present study outcomes.