Antidepressant use in the elderly. Current status of nefazodone, venlafaxine and moclobemide.

Depression is a significant problem in the elderly. Because of aging-related pharmacokinetic and pharmacodynamic changes, it is not possible to automatically extrapolate findings on the efficacy or tolerability of antidepressants from younger to older populations. Venlafaxine inhibits both noradrenaline (norepinephrine) and serotonin (5-hydroxytryptamine; 5-HT) reuptake. Analysis of data from phase II and III trials showed that venlafaxine was comparably effective in the young and in a subset of over 350 elderly patients. Venlafaxine dosage needs to be lowered in the elderly with renal impairment. As a weak cytochrome P450 (CYP) inhibitor, it is unlikely to have clinically significant drug interactions. Venlafaxine may be associated with some increase in supine diastolic blood pressure, especially at dosages above 150 mg/day. Nefazodone is a serotonin uptake inhibitor and serotonin 5-HT2A receptor antagonist. Pooled analysis of about 250 patients found nefazodone to be effective in elderly individuals with moderate or severe depressive symptoms, with or without melancholia, in both primary and recurrent episodes. Nefazodone clearance is reduced in patients with hepatic impairment, and plasma concentrations have been reported to be higher in the elderly. Nefazodone is an inhibitor of the CYP3A4 family. There does not appear to be any increase in the frequency or severity of adverse effects in the elderly. Moclobemide is a selective inhibitor of monoamine oxidase type A. Studies in the elderly have found it to be well tolerated and meta-analysis has shown it to be comparably effective in young and elderly populations, and comparable to other antidepressants in terms of efficacy. Neither age nor renal impairment necessitate dosage adjustment, but hepatic impairment does necessitate dosage reduction. Dietary restrictions are not required. Overall, there is a relative paucity of data on the tolerability and efficacy of newer antidepressants in the elderly, especially those with concomitant medical disorders. Data that are available indicate that venlafaxine, nefazodone and moclobemide have comparable efficacy in older and younger patients.