A comparison of citalopram and paroxetine in the treatment of panic disorder: A randomized, single-blind study

Background: Serotonin Selective Re-uptake Inhibitors (SSRIs) are the drugs of choice for treating panic disorder (PD). In vitro studies have shown dif ferent pharmacodynamic profiles for SSRIs, but their clinical relevance is still unknown. Paroxetine, the SSRI with the strongest serotonergic effect, also shows significant cholinergic and noradrenergic activities. In this c lass of drugs, citalopram is the most selective for serotonin. We compared these two drugs and their effectiveness and tolerability in a sample of pat ients with PD in a two-month treatment course. Method: Fifty-eight patients with PD were randomly assigned to either the paroxetine or the citalopram treatment group in a single-blind, randomized design. Each patient was asse ssed at days 0, 7 and 60 by the Panic Associated Symptoms Scale (PASS), the Sheehan Disability Scale (SDS) and the Fear Questionnaire (FQ). Primary ou tcome measures were the percentage of patients free of panic attacks, antic ipatory anxiety and phobic avoidance in the last week of the trial and the percentage of good responders, as defined by a reduction of at least 50% fr om baseline of both PASS and SDS global scores at day 60. Results: At day 6 0, 86% of patients receiving citalopram and 84% of those receiving paroxeti ne responded well to treatment. No significant differences between the two drugs were found. Both were well tolerated, although sexual side effects an d weight gain were frequent. Anticipatory anxiety decreased significantly a fter the first week of treatment, and no initial worsening in the panic att acks was observed. Conclusion: Paroxetine and citalopram show similar anti- panic properties and a good tolerability profile. Our results support evide nce that the serotonergic system plays a significant role in the anti-panic properties of these two SSRIs.