Electrocardiographic findings during extended clinical trials of fluvoxamine in depression: one years experience

Fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), is used to treat depression. No significant effect on the electrocardiogram (ECG) has been reported during short-term controlled studies of SSRI's. We report a long-term (1 year) multi-center, double-blind controlled study of the ECG during treatment of depression with fluvoxamine (FX), active control medication (TCA), and placebo (PLA).

Initially ECGs were obtained from 1840 physically healthy, depressed outpatients who were treated with FX, TCA, or PLA for 6 weeks. A subset of these patients continued treatment for up to one year. Complete sets of ECGs were obtained from 462 of these patients. Patients whose depression was substantially improved in the initial 6-week study ("responder") received the same medication. Non-responders received a blinded active medication. Pre-treatment, intra-study, and past-treatment ECGs were recorded according to protocol. One blinded electrocardiographer measured and analyzed all ECG data. The effects of each medication upon the ECG were measured and compared.

Of the 462 patients, 311 used FX, 100 used TCA and 51 used PLA. Analyses of ECG data for each treatment focused on changes in ECG measurements; % of normal ECGs, and % of individual ECG findings. The ECG changes during FX treatment were less than or not significantly different from the ECG changes with PLA treatment. The changes with TCA were as expected.

Fluvoxamine treatment of depression for one year was not associated with any significant effect on the ECG.