Efficacy, Tolerability, and Safety of Fluoxetine for Panic Disorder in Adults: A Review.

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) used in the pharmacological treatment of panic disorder. Its efficacy is supported by clinical trials, but the response to treatment and tolerability vary between patients, driving interest in strategies that could improve its clinical use. This review evaluates the effectiveness and side effects of fluoxetine in panic disorder, discusses clinical, pharmacokinetic, and pharmaceutical barriers to treatment, and assesses current and emerging strategies for treatment optimization.  We conducted a structured literature review drawing on two complementary streams of evidence. We reviewed the clinical literature for evidence of fluoxetine efficacy, response, remission, maintenance, adverse effects, tolerability, and discontinuation in panic disorder. A second stream was dedicated to fluoxetine-specific research on pharmacokinetics, pharmacogenetics, formulations, and drug delivery. Clinical conclusions were based on randomized controlled trials and systematic reviews, whereas preclinical and physicochemical investigations were separately addressed as potential future approaches. Randomized trials support the efficacy of fluoxetine for panic disorder across panic symptoms, anxiety, phobic symptoms, global improvement, and functioning. Placebo-controlled evidence suggests that fluoxetine may increase the likelihood of achieving panic-free status during treatment. Fluoxetine has generally been well tolerated in controlled studies, although early activation, gastrointestinal effects, insomnia, and treatment intolerance were noted in some patients. Cytochrome P450 2D6 (CYP2D6) contributes to variability in fluoxetine and norfluoxetine concentrations, but there is insufficient evidence to support the routine use of genotype to guide dosing. Cocrystals, nanoparticles, and intranasal delivery systems can alter physicochemical properties or drug distribution but have not been demonstrated to be clinically helpful in panic disorder. Fluoxetine is a pharmacological option with evidence of efficacy in panic disorder. The clinical value of fluoxetine depends on a balance between efficacy and tolerability. Optimization now should focus on individualized initiation and titration of doses, management of adverse effects, adherence, drug interactions, patient preferences, and ongoing monitoring. Pharmacogenetics, therapeutic drug monitoring, and advanced drug delivery systems are still promising areas of investigation for the future rather than established clinical strategies.