Efficacy and tolerability of milnacipran: an overview

The relative benefits and risks of milnacipran, a novel antidepressant which selectively inhibits the reuptake of serotonin and noradrenaline, have been evaluated in comparative trials against tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs). A total of 2462 patients with major depressive disorders have been investigated. At the optimal dose (50 mg twice a day), the efficacy of milnacipran was equivalent to that of the TCAs, with response rates of approximately 65% in both cases. Milnacipran was consistently effective against all of the principal elements of depression (anxiety, cognitive function, sleep and psychomotor retardation), and did not produce sedation or the emergence of suicidal thoughts. The Clinical Global Impression (CGI-3) score, a measure of the overall therapeutic impact of a treatment, was significantly higher with milnacipran than with TCAs (1.98 versus 1.84, p < 0.05). TCAs were associated with a higher frequency of adverse events than milnacipran, particularly with respect to anticholinergic-like effects; dysuria was the only adverse event occurring twice as frequently with milnacipran than with TCAs. Compared with TCAs, milnacipran was also associated with a lower incidence of cardiovascular adverse events. No haematological abnormalities occurred during treatment with milnacipran, and the incidence of abnormal liver function tests tended to be lower with milnacipran than with TCAs. In comparisons with SSRIs, milnacipran produced significantly higher response rates. The CGI-3 scores were significantly higher in milnacipran-treated patients (2.64 versus 2.32, p < 0.05). The adverse event profiles of the two treatments were similar, as was the incidence of abnormal liver function tests. These studies suggest that milnacipran offers clinical advantages over TCAs in terms of tolerability, and over SSRIs in terms of efficacy. In particular, the lack of cardiovascular adverse events appears to offer advantages in cases of deliberate overdose. To date, 15 such overdoses have occurred; none was fatal and each had a favourable outcome. The reproducible pharmacokinetic characteristics of milnacipran present further advantages over both groups of agents, due to lack of drug accumulation and a low risk of drug interactions.