Side Effects of Antidepressants

By Frank DiVincenzo, MD
Medically reviewed checkmarkMedically reviewed
March 22, 2022

Antidepressants are medicines used to treat depression, a mental health condition that causes prolonged feelings of sadness and hopelessness.

While depression is most often associated with emotions, it can also have physical effects, including headaches, digestive problems, and aches and pains. 

The medication your doctor prescribes will depend on the severity of your symptoms and your health history.

Regardless of which medications are right for you, it’s important to know their potential side effects before taking them. 

In this article, I’ll discuss why antidepressants are prescribed and the various types of antidepressants.

I’ll explain common side effects. 

I’ll also cover who commonly experiences these side effects.

Finally, I’ll explore other things to look out for when you’re taking antidepressants. 

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Why Are Antidepressants Prescribed?

Depression can alter brain chemistry, leading to lower levels of important hormones, such as serotonin, dopamine, and norepinephrine.

Antidepressants are prescribed to help balance these chemicals in your brain. 

Types of Antidepressants 

There are various classes of antidepressants that affect neurotransmitters differently.

In some cases, a combination of antidepressants may be prescribed.

Classes of antidepressants include:

  • Selective serotonin reuptake inhibitors (SSRIs): SSRIs are the most common class of antidepressant prescribed. Often, doctors will prescribe them first due to their effectiveness and tolerability. Additionally, they typically cause fewer unpleasant side effects than other kinds of antidepressants. They increase serotonin levels in your brain by blocking the reabsorption, or reuptake of serotonin into neurons. Common types of SSRIs include: Celexa (citalopram), Lexapro (escitalopram), Paxil (paroxetine), Prozac (fluoxetine), and Zoloft (sertraline). 
  • Serotonin and norepinephrine reuptake inhibitors (SNRIs): As with SSRIs, SNRIs block the removal of neurotransmitters to help balance brain chemistry. In addition to serotonin, SNRIs also increase norepinephrine. Commonly prescribed SNRIs include: Cymbalta (duloxetine), Effexor XR (venlafaxine), Pristiq (desvenlafaxine), and Fetzima (levomilnacipran).
  • Monoamine oxidase inhibitors (MAOIs): MAOIs block the monoamine oxidase enzyme, which breaks down norepinephrine, serotonin, dopamine, and tyramine. Similar to the process of SSRIs and SNRIS, by inhibiting the enzyme, MAOIs increase the levels of the neurotransmitters. Though MAOIs were the first class of antidepressants developed, they are now typically prescribed only if other medications are unsuccessful due to strict dietary restrictions, side effects, and safety concerns. MAOIs prescribed include: Marplan (isocarboxazid), Nardil (phenelzine), and Parnate (tranylcypromine). It also comes in the form of a patch called Emsam (selegiline) that you stick on to your skin. 
  • Tricyclic antidepressants (TCAs): Another older class of antidepressants, TCAs block the reuptake of serotonin and norepinephrine. Doctors usually only prescribe them after you take other antidepressants that cause less side effects and they don’t work for you. A few common TCAs are Tofranil (imipramine), Nopramine (desipramine), and Pamelor (nortriptyline).  
  • Atypical antidepressants: While atypical depressants don’t fit under the four main classes of antidepressants, they function similarly to help with depression: by working to restore the balance of neurotransmitters in your brain. Atypical antidepressants target different chemicals. In some cases, they are prescribed as first-line medication, but usually they’re only prescribed if other antidepressants are ineffective. Some common atypical antidepressants prescribed include: Remeron (mirtazapine), Trintellix (vortioxetine), and Wellbutrin (bupropion).   

Common Side Effects of Antidepressants

Antidepressant side effects differ by medication.

Some side effects can occur when you start taking an antidepressant, but improve after a couple weeks.

However, certain side effects can persist the entire time you take medication.

The side effects of SSRIs and SNRIs may be unpleasant, and, in some cases, serious.

If you’re experiencing any side effects, don’t stop taking medication without speaking with your doctor first, as stopping medication suddenly can cause symptoms to worsen. 

Common side effects of antidepressants include:

Who Experiences Side Effects?

Antidepressants affect everyone differently, causing side effects for some.

The following factors can influence how people may react to antidepressants. 

Medications 

Other medications—including over-the-counter medication—may interact unpredictably with antidepressants, causing more side effects.

Drug interaction may also make antidepressants less effective, so it’s important to tell your doctor all of the medications you’re taking.  

Age

While depression usually starts in late adolescence or early adulthood, it can happen at any age.

According to the FDA, clinical trials showed the antidepressants can cause or worsen suicidal behavior for children and young adults under the age of 25.

Studies suggest there may be an increased potential for clinically significant adverse drug events for elderly people taking antidepressants, including falls and fractures.      

Genes 

According to the Mayo Clinic, studies show that genes may have a hand in determining risk for side effects from antidepressants.

How a close relative reacts to antidepressant may indicate how it will work for you.

More research is being done to see if genetic testing can help assess what antidepressants are best for individuals.

So while genetic testing may be available (though not common) for helping to determine antidepressant choice, it’s not a substitute for a clinical and psychiatric exam. 

Other Things to Look Out For

In addition to common side effects, there are other things to keep in mind when it comes to antidepressants. 

Serotonin syndrome

Taking two medicines that can affect serotonin levels (i.e. migraine medication and an antidepressant) can lead to serotonin syndrome, a drug reaction that results in too much serotonin.

Increasing a dosage of a certain medication you’re taking or starting a new medication can also cause serotonin syndrome. 

Signs and symptoms of too much serotonin include: agitation, high blood pressure, confusion, diarrhea, shivering, headache, and muscle rigidity.

In some cases, serotonin syndrome can lead to death.

Seek medical attention if you experience these severe symptoms: seizures, tremor, high fever, tremor, irregular heartbeat, or unconsciousness.  

Hyponatremia 

Hyponatremia, also known as low blood sodium, is a condition that occurs when your blood has lower than normal sodium level.

Antidepressants can affect hormonal and kidney processes that regulate sodium at healthy levels.

When sodium is diluted, the amount of water in your body increases, causing your cells to swell.

This swelling can cause the following symptoms, which range from mild to severe: nausea, headache, seizures, coma, restlessness, fatigue, confusion, muscle weakness, and vomiting.

Research shows that the highest risk of hyponatremia occurs within the first couple of weeks of starting the medication. 

Diabetes

It’s possible that using SSRIs and TCAs long-term may increase the risk of developing type 2 diabetes, though other factors may cause diabetes to develop.

For instance, it may be that people using antidepressants may gain weight, which increases the risk of type 2 diabetes. 

Suicidal thoughts

FDA-approved antidepressants have a black box warning for the risk of increased suicidal thoughts and behavior for people under the age of 25.

Seek medical help right away if you or a loved one are experiencing suicidal thoughts.

You can also reach the National Suicide Prevention Lifeline at 800-273-8255. 

Sexual issues 

Common sexual side effects that antidepressants can cause, include a low libido (decreased sexual appetite), difficulty reaching orgasm, problems with arousal, erectile dysfunction (ED), which is the inability to get and keep an erection. 

SSRIs are more likely to cause sexual issues than other classes of antidepressants.

For instance, in addition to the previously mentioned side effects, Zoloft can also cause delayed or painful ejacualtion, pain during sex, nonpureperal lactation, penial anesthesia, decrease or loss of sensation in the vagina and nipples, loss of sexual sensation in the penis, prolonged erection of the penis, and reduced sperm count. 

Emotional Blunting     

Antidepressants may cause emotional blunting, which is a term that describes the dulling or numbing of emotional responses.

Those with this common symptom of depression and antidepressants (particularly SSRIs) have limited emotional responses to events.

Some common signs include fatigue, forgetfulness, restlessness, lack of concentration, feeling disconnected, inability to feel happy or sad, and feeling empty.

It can also affect facial expressions and other forms of communication.

Emotional blunting can be experienced from as short as a few minutes to as long as years, depending on what’s causing it. 

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When to See a Doctor 

Most antidepressant side effects are mild, and usually go away after a couple of weeks of starting medication.

Still, you should talk to your doctor if you are experiencing side effects or notice severe changes.

Monitoring blood levels may help determine effectiveness and if adjusting dosage can help.

As previously stated, if the side effects become intolerable, consult your doctor before stopping or reducing medication.

Suddenly stopping your medication may lead to serious symptoms.

If you’re experiencing thoughts of self-harm or suicide, seek medical attention right away. 

Additionally, if you’re experiencing side effects from antidepressants and want to consult a doctor, K Health can help.

Did you know you can get affordable primary care with the K Health app?

Download K to check your symptoms, explore conditions and treatments, and if needed text with a doctor in minutes. K Health’s AI-powered app is HIPAA compliant and based on 20 years of clinical data.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Frank DiVincenzo, MD

Dr. Frank DiVincenzo has been a physician with K Health since 2020. He grew up near Chicago, Illinois, but left the big city to go to college and then attend graduate school in Missouri. He received a Bachelor of Science in Mathematics and a Master of Science in Microbiology before graduating from the University of Missouri–Columbia School of Medicine.

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