SSRI Antidepressants: Their Side Effects, Uses, And MOA

Last Updated: June 10, 2020

Authored by Sharon Levy, MD, MPH

Among the four common classes of depression medications are SSRI antidepressants. In fact, SSRI antidepressant lists contain some of the most well-known depression-treating medications in existence. However, being widely used does not mean that the different types of SSRI antidepressants are safe for all users.

What Are SSRI Antidepressants?

SSRI medications are the most commonly prescribed antidepressants in the United States. Standing for selective serotonin reuptake inhibitors, these popular antidepressants are favored due to their lower risk of side effects compared to other depression drug classes.

Selective serotonin reuptake inhibitors first gained FDA approval in the late 1980s. In the decades since numerous drugs in the class have been approved. In fact, there are more different SSRI antidepressants on the market than there are in any of the other depression drug classes.

The list of SSRI antidepressants with FDA approval is as follows:

Of these, citalopram is the most frequently prescribed due to it being the best tolerated in clinical trials. Other top SSRI antidepressants are escitalopram and fluoxetine.

man in the pharmacy learning how SSRIs work

How Do SSRI Antidepressants Work?

When taking a medication that affects the chemistry of the brain, it is natural to want to know how it works. However, how SSRI antidepressants work is something of a mystery. In fact, how antidepressants work in general is not fully understood as well.

Most researchers within the field believe that SSRI depressants’ mode of action comes down to their interaction with the presynaptic cell. It is believed that they prevent the presynaptic cell from reabsorbing serotonin. As a result, there is more serotonin, a known feel-good chemical, left in the brain, making it easy for it to bind to the postsynaptic receptor. This is what gives SSRIs their name.

Depending on the medication and the person taking it, most popular SSRI antidepressants take at least four weeks to start working. Some take as long as two months.

Uses Of SSRI Antidepressants

As is clear from the name, one of the conditions SSRI antidepressants treat is depression. This is the condition the medicines were developed to alleviate, and they are often prescribed for both major depressive disorder, as well as mild to moderate depression. While there is debate over their effectiveness in treating mild to moderate depression, the fact remains they are prescribed for this.

man using SSRIs to reduce working stress

However, depression treatment may soon be eclipsed by their use in the treatment of anxiety. The use of SSRI antidepressants for anxiety is steadily rising and is currently the second most common application of the drugs.

There are also numerous off-label uses of drugs. While not officially approved for these applications, their use is supported by limited research. These applications include:

  • Obsessive-compulsive disorder
  • Panic disorder
  • Debilitating phobias
  • Bulimia
  • Post-traumatic stress disorder
  • Premature ejaculation
  • Premenstrual dysphoric disorder
  • Fibromyalgia
  • Irritable bowel syndrome
  • Hot flashes
  • Nerve pain

SSRI Antidepressant Side Effects

SSRI antidepressant side effects are known to be less than those caused by other types of depression medication. For example, tricyclic antidepressant side effects are significantly more extensive and felt more severely than those of SSRIs. However, the side effects of antidepressant SSRIs are not non-existent.

There are both short-term and long-term effects of SSRI antidepressants. These include:

  • Drowsiness
  • Dry mouth
  • Insomnia
  • Nervousness, agitation or restlessness
  • Dizziness
  • Headache
  • Blurred vision
  • Rash
  • Blurred vision
  • Agitation or nervousness
  • Pain in the joints or muscles
  • Upset stomach, nausea, or diarrhea
  • Reduced sexual desire
  • Problems with erection or ejaculation

Also, SSRIs are known to be antidepressants that don’t cause weight gain, though this can vary between patients. Ultimately, users cannot know what side effects they will experience until they begin taking the medication.

Food And Drug Interactions

SSRI medications have numerous food and drug interactions. As a result, users need to be honest with their doctor about all medications, drugs, and other substances they are taking, including over-the-counter medications and supplements. The most concerning result of an interaction is serotonin syndrome, which can prove deadly. However, there are many lesser interactions which can be dangerous in their own ways.

Medications that can interact with SSRIs include:

  • Non-steroidal anti-inflammatory drugs, including ibuprofen and Naproxen
  • Medications that thin the blood, including blood clot medications and aspirin
  • Certain asthma medications
  • Lithium, often used to treat mood disorders
  • Triptans, a type of medication that is often used to treat migraines
  • Other depression medications
  • St. John’s Wort

Users should keep in mind that this is not a complete list, and new interactions may be discovered at any time. It is vital that anyone taking SSRI depression medications speaks openly with their doctor about all substances they are using.

With SSRI drugs, the only food interaction of note is with caffeine. When some SSRIs are mixed with caffeine, it can induce heart palpitations, general feelings of sickness, restlessness, and sleep troubles. Any foods or drinks that contain caffeine should be consumed in limited amounts or removed from the diet completely.

Contraindications And Warnings

Not everyone is a good candidate for treatment with SSRI antidepressants. Cautions when taking them include:

  • Those who have bipolar disorder and are currently in a mania period
  • Anyone with a bleeding disorder
  • People with diabetes, both type 1 and type 2
  • Individuals with epilepsy
  • Those with narrow-angle glaucoma
  • Anyone with kidney, heart, or liver problems

SSRIs warnings for use

There is concern over using antidepressants while breastfeeding or pregnant. With SSRIs, doctors will sometimes feel they are safe enough and the need of the mother so great that the risks are worth continued use. However, the mother should be informed as to the dangers.

Driving on medication. When SSRIs are first started, drowsiness is a significant concern. People should not drive or operate heavy machinery until they know how the medication affects them.

As is the case with all depression medications, there is a black box warning on SSRIs. This warning is there because they have the potential to increase the risk of experiencing suicidal thoughts and actions. This risk is greatest in the first months of taking them and is more likely to be experienced by those under the age of 25.

Addiction To SSRI Antidepressants And Its Treatment

While SSRI medications can greatly help those who take them, they are not without their risks. There is always a possibility to become addicted to SSRIs. As with all antidepressants, SSRIs addiction can manifest physically and psychologically. People often cannot understand why they become addicted to their SSRI meds. However, the fact is that long-term use almost always results in some sort of addiction. The point here is that with the right tapering schedule, patients can overcome addiction.

Whether someone feels addicted to them or just wants to stop safely, drug rehab centers offer the right treatment for stopping SSRIs. It is possible to move away from medication use while still living a good life.

Page Sources

  1. What are the real risks of antidepressants? Harvard Health Publishing. 2019.
  2. Ferguson JM. SSRI Antidepressant Medications: Adverse Effects and Tolerability. Journal of Clinical Psychiatry Primary Care Companion. 2001; 3(1): 22–27. doi:10.4088/pcc.v03n0105.
  3. Parmet S. Why do antidepressants take so long to work? UIC Today. 2016.

Published on: October 15th, 2019

Updated on: June 10th, 2020

About Author

Sharon Levy, MD, MPH

After successful graduation from Boston University, MA, Sharon gained a Master’s degree in Public Health. Since then, Sharon devoted herself entirely to the medical niche. Sharon Levy is also a certified addiction recovery coach.


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