Source: Circulation  |  Posted 9 years ago

Citalopram may be effective for the treatment of depression in patients who have discontinued fluoxetine use due to adverse events, suggest the findings of a new study.

About 10 to 20% of patients taking serotonin reuptake inhibitors (SSRIs) discontinue due to adverse events, such as tremor, nausea, and sexual dysfunction. Fluoxetine and citalopram are both widely used SSRIs, but they differ in several ways that may influence their adverse event profiles.

Joseph Calabrese, MD, with the Mood Disorders Program, at the Case Western Reserve University School of Medicine, Cleveland, Ohio, United States, and colleagues investigated 55 outpatients with DSM-IV major depressive disorder and a confirmed history of intolerance to fluoxetine (mean final dose = 24.6 mg/day).

Patients were switched to citalopram (20 mg/day) after a 2- to 4-week single-blind placebo washout period. During a 6-week, open-label treatment protocol, citalopram could be titrated up to 40 mg/day.

Efficacy was evaluated using the Hamilton Rating Scale for Depression (HAM-D), the Clinical Global Impressions (CGI) scale, and several other measures. Response was defined as a CGI-Improvement score at endpoint of 1 or 2. Safety and tolerability were also evaluated.

All but 3 of the 55 patients (95%) completed the citalopram trial, and none of those who terminated did so because of adverse events. The most commonly reported adverse events were pharyngitis (15%) and constipation (11%). The rate of recurrence of the fluoxetine-associated adverse events was low, with headache (3 [27%] of 11 cases), nausea (2 [22%] of 9 cases), and decreased libido (5 [18%] of 28 cases) being the most common.

Beginning in the first week of citalopram treatment, patients' HAM-D scores improved significantly from baseline (p<.001). The intent-to-treat CGI response rate was 65% at study endpoint.

"These data suggest that fluoxetine-intolerant patients can be treated effectively with citalopram," Dr. Calabrese and colleagues conclude.

According to the researchers, the low attrition rate and tolerability of citalopram among participants may be due to citalopram's short half-life, its slow titration schedule, lack of active metabolites, increased selectivity, and lack of inhibition of the cytochrome system compared to fluoxetine.