What Are Antidepressants? Antidepressant Types / Classes

Bipolar Medications Library

It's obvious from the name that antidepressants are medications to relieve depression, but what are all the different types or classes? There are SSRIs, SNRIs and SSNRIs; there are MAOIs and TCAs; and then there are a few just lumped into the category "atypical antidepressants." From Prozac to Cymbalta, from Elavil to Parnate, from Effexor to Zoloft, antidepressants come in more shapes and sizes than jelly beans!

Let's take a closer look at each family of antidepressants, starting with the one most people have heard about, the SSRIs.

• SSRIs
  SSRI stands for selective serotonin reuptake inhibitor. These medications work by preventing the neurotransmitter serotonin from being reabsorbed by the nerve cell that released it, thus forcing the serotonin to remain actively working, which has been shown to ease depression in some patients.

  SSRIs include:

  • Celexa (citalopram)
    
  • Lexapro (escitalopram)
    
  • Luvox (fluvoxamine)
    
  • Paxil (paroxetine)
    
  • Prozac (fluoxetine)
    
  • Zoloft (sertraline)

• SNRIs and SSNRIs
  These two terms are essentially synonymous. SNRI stands for serotonin norepinephrine reuptake inhibitor, while SSNRI stands for selective serotonin norepinephrine reuptake inhibitor, but there really isn't any appreciable difference.
  
  The drugs which inhibit reuptake of both the neurotransmitters serotonin and norepinephrine include:
  • Cymbalta (duloxetine), used to treat both depression and some types of pain.
  • Effexor (venlafaxine)
  • Serzone (nefazodone). The brand name Serzone has been withdrawn from use in the U.S. and several other countries due to the possibility of liver failure, but the generic nefazodone is still available.
  • Milnacipran, currently in clinical trials in the U.S. This antidepressant is being studied for its effectiveness in treating fibromyalgia as well as depression. It is sold under the trade names Dalcipran in Portugal and Ixel in France.

• Tricyclics (TCAs)
  The name "tricyclic antidepressant" came from the chemical structure of many of the drugs in the class - three rings (even though they don't all have this structure). They also work by blocking the reuptake of serotonin and/or norepinephrine, but not selectively. Because they have been around for a long time, they are usually sold in generic rather than brand name form, so we've listed the generic names first here. The tricyclics include:
  • Amitriptyline (Elavil, Endep)
  • Amoxapine (Asendin)
  • Clomipramine (Anafranil)
  • Desipramine (Norpramin, Pertofrane)
  • Doxepin (Adapin, Sinequan)
  • Imipramine (Tofranil)
  • Maprotiline (Ludiomil)
  • Nortriptyline (Pamelor, Aventyl)
  • Protriptyline (Vivactil, Triptil)
  • Trimipramine (Surmontil, Rhotrimine)

• MAOIs
  MAOI stands for monoamine oxidase inhibitors. These work by blocking an enzyme -- monoamine oxidase or MAO -- that breaks down neurotransmitters. Since low levels of these chemicals are associated with depression, making more of the neurotransmitters available -- particularly serotonin and norepinephrine -- may help relieve depression. Because of the way MAOIs work, there are a large number of food and drug interactions possible.

  MAOI antidepressants include:

  • Marplan (isocarboxazid)
  • Nardil (phenelzine)
  • Parnate (tranylcypromine)
  • Manerix (moclobemide) (available outside the United States)
  • Emsam (selegiline)

  If you are taking or talking about taking an MAOI antidepressant, you should read MAOIs and Diet and Side Effects of MAOIs.

• Atypical Antidepressants
  Drugs in this class are called "atypical" because they are chemically unrelated to any other class of antidepressants. Three commonly used antidepressant medications fall into this category:
  • Desyrel - better known by the generic name trazodone
  • Remeron (mirtazapine)
  • Wellbutrin (bupropion) - also sold as the anti-smoking drug Zyban. Wellbutrin works predominantly on the neurotransmitter dopamine.

The Bottom Line
If you are depressed for a long enough period of time to need the help of a medication, there are many, many drugs available that can make a difference. If one doesn't work, you can ask to try another. Once you start an antidepressant, your mood should be monitored closely, and not just to make sure it is working. Any of these medications can cause antidepressant-induced mania or hypomania if you have bipolar disorder, or may potentially uncover undiagnosed bipolar disorder. If this happens, your doctor may prescribe a mood stabilizer to go along with the antidepressant.