What Are the Negative Effects of Antidepressants?

Common and Serious Side Effects

Paxil
Paxil. Joe Raedle / Staff / Getty Images

All medications, including antidepressants, can produce unwanted negative effects that we refer to as side effects.

How to Deal With Side Effects

Some of these negative effects may be quite mild while others may be more severe. In addition, they may go away or become less severe in time. If you experience problems with side effects, you should mention these to your doctor as he or she may be able to either give you strategies for coping with the side effects or prescribe a different antidepressant for you that has fewer or more tolerable side effects.

Don't Stop Your Medication Without Speaking to Your Doctor

Keep in mind, however, that it is never a good idea to stop taking your antidepressant without first discussing it with your doctor. An unpleasant set of symptoms known as discontinuation syndrome may occur if you stop taking your medication too abruptly. These symptoms include electric shock sensations, tingling, vivid dreams, hallucinations, sweating, muscle pain, blurred vision, insomnia, anxiety, irritability, agitation, upset stomach and fatigue.

It's always best to taper off of your antidepressant very slowly with your doctor's guidance. This gives your brain time to get used to the changes and you will notice fewer effects if you stick with your doctor's plan.

Common Side Effects

Some of the more common negative effects that many patients experience with antidepressants include  dizziness, fatigue, blurred vision, sexual side effects, weight gain, constipation, insomnia, dry mouth, nausea and anxiety.

Your doctor will be able to offer you appropriate coping strategies for many of these or may also be able to make changes in your dose or transition you to a different medication that you can better tolerate.

Serious Side Effects

While many of the most common side effects are not cause for excessive concern, there are certain rare, but more serious side effects, that you should be aware of.

Among these are:

  • Serotonin Syndrome

This side effect is linked to the use of antidepressants called selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). Serotonin syndrome occurs when a neurochemical in the brain called serotonin reaches dangerously high levels. It is generally triggered when an SSRI or SNRI medication is used in combination with a second medication that also affects serotonin levels, such as another antidepressant.

Symptoms of serotonin syndrome include confusion, agitation, muscle twitching, sweating, shivering and diarrhea.  In addition, severe cases may include symptoms such as a very high fever, seizures, irregular heartbeat and unconsciousness.

If a person begins to exhibit any the above symptoms, medical care should be sought immediately as this condition can be life-threatening.

  • Hyponatremia

Hyponatremia is a condition in which the sodium, or salt, levels in the blood fall to abnormally low levels. When this happens, dangerous amounts of fluid can build up inside the body's cells.

This side effect can occur with SSRIs because these drugs can potentially impact the effects of a hormone involved in regulating sodium and fluid levels within the body. Older people may be especially prone to hyponatremia.

Mild cases of hyponatremia can cause symptoms such as feeling ill, headache, muscle pain, loss of appetite and confusion. In more severe cases, people may also experience such symptoms as listlessness and fatigue, disorientation, agitation, psychosis and seizures. In addition, hyponatremia has the potential to lead to coma or death.

People who experience even mild symptoms of hyponatremia should seek immediate medical care.

  • Suicidal Thoughts

You should be aware that when you're first starting an antidepressant, you may experience a temporary worsening of your depression and potentially even increased thoughts of suicide. Studies indicate that this may be especially true for people younger than age 25.

If you, or someone you are caring for, experience any worsening of depression, increased thoughts of suicide or death or unusual changes in behavior in the first weeks after starting a new antidepressant, it is important to get medical assistance immediately.

  • Allergic Reactions

Allergic reactions can occur with antidepressants, either because a person is allergic to the active ingredient of the medication or because he or she is allergic to the dyes, fillers or other inactive ingredients present in the pill or capsule.

Symptoms of an allergic reaction can include swelling, itchy rash, hives, blisters or difficulty breathing. 

A severe allergic reaction can become life threatening if it blocks a person's ability to breathe. Medical help should be sought for an allergic reaction, especially if there is swelling in the face or breathing difficulty.

  • Mania

In people who are susceptible to bipolar disorder, medications like antidepressants can potentially trigger an episode of mania.

Symptoms of mania include increased energy and activity, problems with sleeping, racing thoughts, impulsive behavior, grandiose thinking, extreme elevation of mood, irritability and pressured speech.

While mania is not necessarily life threatening, it will require medical assistance to treat.

  • Seizures

Certain antidepressants can increase a person's risk of having a seizure. In some cases, a seizure may be triggered in a person who has never had one before. Most antidepressants do not increase seizure risk, although Wellbutrin (bupropion) is the antidepressant that is most likely to trigger one. Certain older antidepressants called tricyclics can increase a person's seizure risk as well. Generally, the newer antidepressants are less likely to trigger seizures.

Seizures involve such symptoms as uncontrollable jerking movements of the arms and legs, staring spells, confusion, abnormal sensations and loss of consciousness.

All seizures should be reported to a doctor. If it is the first time a person has had a seizure then emergency services should be summoned.

Call 911 immediately if:

  • A seizure lasts more than five minutes
  • The person does not wake up
  • Another seizure begins immediately afterward
  • The seizure occurs in water
  • The person is pregnant, injured or has diabetes
  • There is anything unusual about the seizure compared to others that the person has had before

Sources:

Bressert, Steve.  "The Causes of Bipolar Disorder (Manic Depression)."  Psych Central.  Psych Central.  Published:   February 23, 2007.  Last reviewed:  By John M. Grohol, Psy.D. on January 30, 2013.   Accessed:  December 8, 2015.

Mayo Clinic Staff.  "Antidepressants: Get tips to cope with side effects."  Mayo Clinic.  July 9, 2013.  Mayo Foundation for Medical Education and Research.  Accessed:  December 8, 2015.

"Seizures."  A.D.A.M Medical Encyclopedia.  MedlinePlus.  U.S. National Library of Medicine.  Last updated: By Amit M. Shelat, DO, FACP on February 3, 2015.  Reviewed by:  Verimed Healthcare Network; David Zieve, MD, MHA; Isla Ogilive, PhD and the A.D.A.M. Editorial team.  Accessed:  December 8, 2015.

"Side Effects of Antidepressants."  NHS Choices. National Health Service.   Last Reviewed:  October 14, 2014.  Accessed:  December 8, 2015.

Warner, Christopher H. et. al. "Antidepressant Discontinuation Syndrome." American Family Physician 74.3 (2006): 449-56.

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