What are the different types of antidepressants?

There are many antidepressants on the market today. Why do we need so many different medications to treat the same condition? The answer is simply because not every antidepressant is effective or well tolerated for any given person. Most antidepressants work by either altering chemicals in the brain (neurotransmitters) that regulate mood or the site where these chemicals work (receptors).

The two oldest classes of antidepressants, developed in the 1950s, are the tricyclic antidepressants and the monoamine oxidase inhibitors (MAOIs). While very effective, these two classes of medications have more side effects and risks associated with them than many of the newer antidepressants.
In the 1980s through 1990s, a new class of medicines called selective serotonin reuptake inhibitors (SSRIs) came to market and revolutionized depression treatment. They are well known by their brand names -- Prozac, Paxil, Celexa, Zoloft and Lexapro. These medications are better tolerated and safer than earlier therapies. Unfortunately, not everyone responds well to this class of medications and some people experience undesirable side effects.
Another class of antidepressant was introduced after the SSRIs called serotonin norepinephrine reuptake inhibitors (SNRIs). The brand names of medications in this class include Cymbalta, Effexor, and Pristiq. For reasons not well understood, some people did better with this class of medication than the SSRIs.  
Wellbutrin is a commonly prescribed antidepressant in its own class and works mainly on the neurotransmitters norepinephrine and dopamine.
A less frequently prescribed class of antidepressants is called “atypical antidepressants” or “serotonin modulators.” They include the medications Desryl, Serzone and Remeron. This class of antidepressants have less sexual side effects but tend to be associated with more weight gain and sleepiness.
Finally, there are several new antidepressants that offer some advantages to the older medications. While promoted as having fewer side effects or helping better with particular symptoms of depression, these claims have not all been fully validated. Three recent antidepressants approved in the US include Viibryd, Fetzima and Brintellix.
We still don’t know exactly how each medication fully works or who will respond to which medicine. Whatever helps you the most and has the fewest side effects is the right medication for you. 
The following are the different types of antidepressants:
  • Selective serotonin reuptake inhibitors (SSRIs): Prescribed for generalized anxiety disorder, social phobia, obsessive-compulsive disorder, panic disorder, and post-traumatic stress disorder. Possible side effects include nausea, diarrhea or constipation, sexual dysfunction, insomnia, headache, weight gain or loss, dry mouth, and sweating. In rare cases they worsen anxiety symptoms. Examples of SSRIs are citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), fluvoxamine (Luvox), paroxetine (Paxil), and sertraline (Zoloft).
  • Dual reuptake inhibitors (acting on both serotonin and norepinephrine): Prescribed for generalized anxiety disorder and post-traumatic stress disorder. Possible side effects include nausea, headache, insomnia, dizziness, sexual dysfunction, constipation, dry mouth, loss of appetite, and at higher doses, a rise in blood pressure. Examples of dual reuptaek inhibitors are venlafaxine (Effexor) and duloxetine (Cymbalta).
  • Tricyclic antidepressants (TCAs): Prescribed for severe generalized anxiety disorder, panic disorder, obsessive-compulsive disorder (clomipramine), and post-traumatic stress disorder. Possible side effects include dizziness, drowsiness, dry mouth, weight gain, blurred vision, constipation, trouble urinating, and disturbance of heart rhythm (toxic overdoses can cause life-threatening heart arrhythmias). Examples of TCAs are amitriptyline (Elavil), clomipramine (Anafranil), imipramine (Tofranil), and doxepin (Sinequan).
  • Monoamine oxidase (MAO) inhibitors: Prescribed for social phobia and panic disorder. Possible side effects include dizziness, headache, disturbed sleep, diarrhea, drowsiness, craving for sweets, and weight gain and, rarely, dangerously high blood pressure if foods containing tyramine are eaten. Because of the risk of serious side effects, MAO inhibitors are generally used only when other approaches fail. Examples of MAOs are isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate).

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.