Differential Pharmacology of Newer Antidepressants

New antidepressants have become available for clinical use in the 1990s. Before this decade, thedrugs 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 firstmajor departures from the pharmacology of the tricyclics. Following the introduction in 1988 of thefirst serotonin selective reuptake inhibitor (SSRI) in the United States, the options have expanded andnow 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 choiceof an antidepressant for clinical use. This review summarizes some of the major pharmacokinetic andpharmacodynamic similarities and differences among these drugs.