SRRIs affect neurotransmitters, chemicals that nerve cells in the brain use to communicate with one another.

Selective serotonin reuptake inhibitors, or SSRIs, are the most commonly prescribed class of antidepressants.

Fluoxetine (Prozac) was the first SSRI on the market in 1987.

SRRIs affect neurotransmitters, which are chemicals that nerve cells in the brain use to communicate with each another.

Specifically, the drugs block the reabsorption, or the reuptake, of the neurotransmitter serotonin.

These medicines are used to help treat:

  • Moderate to severe depression
  • Anxiety disorder
  • Panic disorder
  • Obsessive compulsive disorder (OCD)
  • Eating disorders, such as anorexia or bulimia
  • Social phobia or social anxiety disorder

Common SSRIs

Commonly prescribed SSRIs include:

  • Citalopram (Celexa)
  • Fluoxetine (Prozac)
  • Escitalopram (Lexapro)
  • Paroxetine (Paxil)
  • Sertraline (Zoloft)

SSRI Side Effects

The Food and Drug Administration (FDA) requires that antidepressants carry a black-box warning because of the risk of suicidal thoughts or behaviors in children, teens, and young adults.

They continue to be prescribed, however, because SSRIs typically pose fewer side effects than other types of antidepressants.

Nevertheless, they may cause some side effects, such as:

  • Nausea
  • Agitation, nervousness, or restlessness
  • Dizziness
  • Reduced sexual desire or sexual performance
  • Insomnia
  • Drowsiness
  • Headache
  • Dry mouth
  • Weight gain or loss
  • Vomiting or diarrhea

SSRI Withdrawal and Discontinuation Syndrome

SSRIs typically aren't considered addictive, but physical dependence can occur.

Stopping treatment abruptly or missing several doses of the medicine may cause withdrawal effects, a phenomenon known as discontinuation syndrome.

Symptoms of SSRI withdrawal include:

  • Dizziness and vertigo
  • Headache
  • Confusion and irritability
  • Nausea
  • Lethargy
  • Flu-like symptoms

Talk to your doctor before you stop taking an SSRI for direction on how to discontinue the drug.

By reducing the dose gradually, you can lower your chances of experiencing this problem.

SSRI and Pregnancy

Taking an antidepressant during pregnancy may cause risks for an unborn baby, but for some pregnant women not treating depression poses risks, too.

Talk to your doctor about the benefits and risks of taking a SSRI during pregnancy.

Some antidepressants can enter breast milk but there's no conclusive evidence that this is harmful to a breastfeeding infant.

Nevertheless, talk to your doctor about the risks and benefits of taking a SSRI if you are breastfeeding.


Serotonin and norepinephrine reuptake inhibitors (SNRIs) are another, newer class of antidepressants.

While SSRIs block the reuptake of serotonin, SNRIs block the reuptake of both serotonin and norepinephrine.

Some studies indicate that SNRIs may have better pain-relieving properties and might be more effective at treating certain forms of depression.

However, other studies show mixed results.

More research is needed to determine how these types of antidepressants compare to each other.

Editorial Sources and Fact-Checking

  • SSRIs, Mayo Clinic.
  • A Brief History of Antidepressants, Time.
  • SNRIs, Mayo Clinic.


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