Pharmacotherapy for Depression

By | March 7, 2012

Pharmacological treatments have gained popularity during the last 50 years as a method of treatment intervention for depression as well as for many other psychological disorders. They have been proven effective in ameliorating the symptoms for a large percentage of depressed individuals and are now the most common form of treatment for depression. The constraints of this chapter do not allow for a detailed discussion of antidepressant drugs, but we briefly present them below.

Commonly Used Drugs

Antidepressant drugs are classified depending on their chemical structure and how they work, and all categories of antidepressants tend to be comparably efficacious (Depression Guideline Panel). They can be categorized into four basic groups: (a) tricyclics (TCAs), (b) monoamine oxidase inhibitors (MAOIs), (c) serotonin reuptake inhibitors (SRIs), and (d) atypical drugs. Drugs in the current antidepressant pharmacopoeia are in general hypothesized to work by altering the activity of biogenic amine neurotransmitters (e.g., acetylcholine, norepinephrine, serotonin, and dopamine). This view is oversimplified, as antidepressants also affect presynaptic receptors, postsynaptic second messengers, and neurophysiologic response systems.

Table Tricyclic Antidepressants

Chemical name Trade name
Amitriptyline Elavil, Endep
Amoxapine Asendin
Clomipramine Anafranil
Desipramine Norpramin, Pertofrane
Doxepin Sinequan, Adapin
Imipramine Tofranil, Tipramine, Norfranil
Maprotiline Ludiomil
Nortriptyline Pamelor, Aventyl
Protriptyline Vivactil
Trimipramine Surmontil

Table Monoamine Oxidase Inhibitors

Chemical name Trade name
Brofaromine Consonar
Isocarboxazid Marplan
Moclobemide Manerex
Phenelzine Nardil
Tranylcypromine Parnate

In terms of efficacy of antidepressants, the superiority of tricyclic antidepressants to placebo in treating unipolar major depression has been repeatedly demonstrated in randomized clinical trials, although tricyclic antidepressants have received somewhat less support for the treatment of other depressive variants, such as atypical or subsyndromal depression. monoamine oxidase inhibitors are comparably effective to tricyclic antidepressants and may be more effective than tricyclic antidepressants and SRIs in treating individuals with atypical depression or reversed vegetative symptoms (e.g., hypersomnia, hyperphagia, and behavioral activation). Their efficacy with severe levels of depression, however, is less certain, as some research indicates that they are not as effective as tricyclic antidepressants or SRIs. In addition, the use of monoamine oxidase inhibitors has been constrained by an unfavorable side-effect profile as well as drug interactions and dietary restrictions prohibiting the ingestion of tyramine-containing foodstuffs (generally, aged or fermented foods and certain fruits and alcoholic beverages). The recent development of the “reversible” MAOIs, which promise a more favorable side-effect profile and fewer dietary and drug interactions, may increase their currency as first-line agents against depression.

Table Serotonin-Specific Reuptake Inhibitors

Chemical name Trade name
Citalopram Celexa
Fluoxetine Prozac
Fluvoxamine Luvox
Paroxetine Paxil
Sertraline Zoloft

Table Atypical Antidepressants

Chemical name Trade name
Bupropion Wellbutrin
Mirtazapine Remeron
Nefazodone Serzone
Reboxetine Edronax
Trazadone Desyrel, Trazon, Trialodine
Venlaxafine Effexor

SRIs have fewer adverse side effects and are far less lethal in overdose than are tricyclic antidepressants and irreversible monoamine oxidase inhibitors. This in large part accounts for their popularity and the frequency of their use. Because of their relatively benign side-effect profiles and low toxicity, their use has become commonplace. The efficacy of and response time to SRIs are similar to those of tricyclic antidepressants.

Certain other drugs, although they do not fit into any of the first three major categories of tricyclic antidepressants (TCAs), MAOIs, or SRIs, are classified as “atypical” and have also been found to be effective for treating depressive symptoms. Examples of atypical antidepressants currently available are trazodone, nefazodone, bupropion, venlafaxine, and reboxetine.