Differential pharmacology of newer antidepressants.

New antidepressants have become available for clinical use in the 1990s. Before this decade, the drugs available to treat depression consisted essentially of lithium, the monoamine oxidase inhibitors, and tricyclic antidepressants. Trazodone and bupropion, introduced in the mid-1980s, were the first major departures from the pharmacology of the tricyclics. Following the introduction in 1988 of the first serotonin selective reuptake inhibitor (SSRI) in the United States, the options have expanded and now include four SSRIs (fluoxetine, sertraline, paroxetine, fluvoxamine), nefazodone, venlafaxine, and mirtazapine. Citalopram and reboxetine are expected to be available by the end of the decade. These newer drugs possess a variety of pharmacological characteristics that are relevant to the choice of an antidepressant for clinical use. This review summarizes some of the major pharmacokinetic and pharmacodynamic similarities and differences among these drugs.