Moclobemide, a novel benzamide, is a reversible inhibitor of monoamine oxidase-A (RIMA). It has been extensively evaluated in the treatment of a wide spectrum of depressive disorders. Comparative studies have shown that the drug is more effective than placebo and as effective as other antidepressants. In terms of efficacy, moclobemide offers no more benefits than do existing agents. On the other hand, moclobemide is better tolerated than tricyclic antidepressants and, unlike irreversible monoamine oxidase inhibitors, has a much lower propensity to cause a 'cheese reaction' (a potentially fatal syndrome caused by an interaction with tyramine-rich foods). These are significant clinical benefits, particularly in elderly patients. Furthermore, moclobemide lacks significant effects on psychomotor performance and cognitive function, has few clinically important drug interactions and is safe on overdose. The drug has a relatively short plasma elimination half-life, a property that allows a change to an alternative agent within 24 hours in cases of nonresponse. Since it is well tolerated, therapeutic dosages can often be achieved from the onset of treatment. These benefits need to be considered against the potential risks of moclobemide therapy. To date, the most significant hazards of therapy appear to arise from drug interactions with clomipramine or selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors, where the occurrence of the serotonin syndrome is potentially fatal. Similarly, in preclinical tests moclobemide has been shown to potentiate the effects of pethidine (meperidine) and dextropropoxyphene, so that combined use of moclobemide is a useful addition to the therapeutic agents used for depressive disorders.(ABSTRACT TRUNCATED AT 250 WORDS)