Selective serotonin reuptake pharmacological properties

FIGURE 6-33. Shown here is the icon of a selective serotonin reuptake inhibitor (SSRI). In this case, four of the five pharmacological properties of the tricyclic antidepressants (TCAs) (Fig. 6-27) were removed. Only the serotonin reuptake inhibitor (SRI) portion remains thus the SRI action is selective, which is why these agents are called selective SRIs. 

Fluoxetine (Prozac /Lilly), paroxetine (Paxil /GlaxoSmithKilne), and sertraline (Zoloft /Pfizer) are selective serotonin reuptake inhibitors (SSRIs) and are useful in the treatment of depression. These agents potentiate the pharmacological actions of the neurotransmitter serotonin by preventing its reuptake at presynaptic neuronal membranes. In addition to its SSRI properties, venlafaxine (EfFexor /Wyeth-Ayerst) also appears to be a potent inhibitor of neuronal norepinephrine reuptake and a weak inhibitor of dopamine reuptake thereby enhancing the actions of these neurotransmitters as well. Venlafaxine is indicated for use in anxiety and depression. 

SSRIs were developed in an attempt to formulate reuptake-blocking drugs that lacked the troublesome side effects of TCAs. Of the five pharmacological properties of TCAs—blockade of muscarinic receptors, blockade of histamine Hj receptors, blockade of aj-adrenergic receptors, norepinephrine reuptake blockade, and serotonin reuptake inhibition—only the last remains intact in SSRIs. This selectivity has... 

Thus, reboxetine is the logical pharmacological complement to the SSRIs—since it provides selective noradrenergic reuptake inhibition greater than serotonin reuptake inhibition but without the undesirable binding properties of the tricyclic antidepressants. The discovery of reboxetine has given rise to the questions What is the... 

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