Atypical antidepressants

By Mayo Clinic Staff

Atypical antidepressants are not typical — they don't fit into other classes of antidepressants. They are each unique medications that work in different ways from one another.

How atypical antidepressants work

Atypical antidepressants ease depression by affecting chemical messengers (neurotransmitters) used to communicate between brain cells. Like most antidepressants, atypical antidepressants work by changing the levels of one or more of these naturally occurring brain chemicals.

Atypical antidepressants affect neurotransmitters including dopamine, serotonin and norepinephrine. Changing the balance of these chemicals seems to help brain cells send and receive messages, which in turn boosts mood.

Atypical antidepressants approved to treat depression

The Food and Drug Administration (FDA) has approved these atypical antidepressants to treat depression:

  • Bupropion (Wellbutrin, others)
  • Mirtazapine (Remeron)
  • Nefazodone
  • Trazodone (Oleptro)

Side effects of atypical antidepressants

Common side effects with most antidepressants, including atypical antidepressants, include dry mouth, constipation, and dizziness or lightheadedness. For antidepressants that cause sleepiness, be careful about doing activities that require you to be alert, such as driving a car, until you know how the medication will affect you. Because of the different way atypical antidepressants work, each also has unique characteristics and side effects.

Bupropion may be a good choice if you have low energy caused by depression or if you're trying to quit smoking. It's sometimes prescribed to ease nicotine cravings under the brand name Zyban. Bupropion doesn't cause sexual side effects or weight gain as several other antidepressants do, and it's sometimes prescribed to counter the sexual side effects of another antidepressant. However, bupropion can cause or worsen anxiety in some people. Additional side effects, among others, may include:

  • Headache
  • Weight loss
  • Nausea and loss of appetite
  • Increased heartbeat
  • Insomnia

Mirtazapine is generally taken before bed because it can make you sleepy. Additional side effects, among others, may include:

  • Increased appetite
  • Weight gain
  • Increased cholesterol and triglycerides

Nefazodone may help ease anxiety as well as depression, but it can make you sleepy. It seems less likely to cause sexual side effects than do some other antidepressants. Additional side effects, among others, may include:

  • Headache
  • Insomnia
  • Weakness
  • Agitation
  • Nausea
  • Low blood pressure
  • Blurred vision

Trazodone causes sleepiness and can help with anxiety. Like mirtazapine, it's usually taken at bedtime. It may be prescribed alone or along with other antidepressants to help with sleep. Additional side effects, among others, may include:

  • Blurred vision
  • Headache
  • Extreme tiredness (fatigue)
  • Nausea
  • Muscle aches or pains
  • Diarrhea
  • Irregular heartbeat
  • Sudden drop in blood pressure when standing (orthostatic hypotension)
June 25, 2013 See more In-depth