This paper reviews the cardiovascular effects of fluoxetine and other selective serotonin reuptake inhibitors comparing with those of tricyclic antidepressants. The authors survey the electrophysiological mechanisms and the recent data referring on drug's actions on different ionic currents/channels. The paper primarily focuses on preclinical data, showing various effects of fluoxetine and citalopram on cardiac and smooth muscle preparations and on cardiac ionic currents. At concentrations of 0.5-50 microM, fluoxetine and citalopram exhibit depressant effects on Ca(2+)- and Na(+)-dependent electrophysiological parameters of different cardiac preparations and on cardiac Ca2+ current. At concentrations of 0.1-10 microM, fluoxetine and citalopram elicit relaxation of both vascular and intestinal smooth muscles. These results provide evidence for inhibition of cardiac Na+, Ca2+ and more recently K+ channels by fluoxetine and citalopram at concentrations close to therapeutic level. The inhibition of cardiac Ca2+, Na+ and K+ and vascular Ca2+ channels by fluoxetine and citalopram may explain most cardiovascular side effects observed occasionally with the drugs during the chronic treatment. The inhibitory effects on cardiac Ca2+, Na+ and K+ channels of fluoxetine and citalopram may result in antiarrhythmic/proarrhythmic actions. Thus fluoxetine, citalopram and other selective serotonin reuptake inhibitors similarly to tricyclic antidepressants, may exhibit cardiovascular depressant effects. The paper summarizes drug interactions that may lead risk of arrhythmia and vascular side effects. Taking all these into consideration, in depressed patients having also cardiac or liver disorders, these antidepressants should be also more rigorously applied.