Atypical Antidepressants

Atypical antidepressants are those drugs that do not fit into any of the other three general classes of antidepressants [tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and monoamine oxidase inhibitors (MAOIs)]. They differ from the typical antidepressants in terms of their effects at receptor sites, their presumed mechanism of action, and their side effect profiles. In addition, these drugs differ from themselves. So, atypical antidepressants can be considered a sort of “wastebasket” category.

Trazodone (Deseryl)

• acts via serotonic agonism

• produces sedating effects

• is not a good anti-depressant bc high doses are needed  puts pts to sleep

Its main use is as a sleeping adjunct (50-100mg). Unfortunately, one of its major side effects in males is priapism. Males can experience long painful erections – commonly seen with high doses of the drug, but is not unheard of with low doses. Surgical intervention is often required to prevent permanent sexual impairment. So, all males should be warned of this possible side effect when being prescribed this drug as a sleeping aid.

Nefazodone (Serzone)

• also acts via serotonic agonism

• also sedates, but not to the same degree as Trazodone

• used in cases of mild to moderate depression + anxiety

• is not as effective in pts with severe depression

Venlafaxine (Effexor)

• has both norepinephrine (NE) and serotonin reuptake properties

• is different from traditional tricyclic antidepressants in that it does not produce anti-cholinergic effects, sedation from blocking histamine receptors, or orthostatic blood pressure problems

• can actually increase rate of hypertension (increased amt of NE  hypertension); therefore, we must monitor pts with hypertension very closely

Mirtazepine (Remeron)

• is tetracyclic

• works via serotonin receptors

• may produce extreme weight gain and sedation; therefore, it is a reasonable drug for pts who have lost a lot of weight due to their depression

• is often used to treat melancholic depression

Category: Pharmacology Notes