Common Antidepressant Side Effects

Taking an antidepressant can be an effective way to help treat a mental health condition like depression or anxiety. However, these medications can also create unwanted side effects for some people. If you or a loved one plans to start taking an antidepressant, it’s important to know what to expect.

This article provides an overview of potential side effects for commonly prescribed antidepressants. While this information can support you on your mental health journey, this article is for learning purposes only and isn’t a substitute for medical advice.

Understanding Antidepressant Side Effects

Antidepressants are often used in mental health treatment to help reduce symptoms of depression, anxiety and other disorders. The Cleveland Clinic website explains how they work.

“In general, antidepressants change the way your brain uses certain chemicals (called neurotransmitters) to better regulate your mood and behavior. More specifically, they affect neurotransmission involving serotonin, norepinephrine and, less commonly, dopamine. The different types of antidepressants all work differently to do this.”

Side effects can occur when the medication affects neurotransmitter systems in other parts of your body, not just in your brain. Serotonin-norepinephrine reuptake inhibitors (SNRIs) affect the neurotransmitters serotonin and norepinephrine in the brain. These neurotransmitters are chemical messengers that regulate mood, sleep, memory, and more. Selective serotonin reuptake inhibitors (SSRIs), the most common class of antidepressant, steadily increase the amount of available serotonin in your brain. Serotonin is a powerful neurotransmitter that regulates your mood, bowel movements, sleep, blood clotting, and more.

Not everyone will experience the same side effects, and some people may feel side effects much more than others. Your genes can play a big role in how you may respond to certain medications.

Initial vs. Long-Term Side Effects

Some side effects are more common when you first start a new medication or when your clinician increases your dose. For example, you may initially experience nausea, headache or fatigue. You may feel anxious or have trouble sleeping. These side effects can get better or go away on their own after a few weeks, as your body adjusts.

Other side effects may not go away as easily or may start after you have taken the medication for a longer period of time. For example, you may gain weight or have problems with sexual dysfunction. You may feel “emotional blunting,” or that you are not as responsive emotionally as you once were.

Common Side Effects by Medication Classes

Different classes of medications may cause you to experience specific types of side effects. Your clinician will likely prescribe you a medication that fits into one of the following classes:

Selective Serotonin Reuptake Inhibitors (SSRIs)

SSRIs include medications such as fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), citalopram (Celexa) and escitalopram (Lexapro). A Mayo Clinic article on antidepressants shares why you may recognize many of these names: “Health care providers often start by prescribing an SSRI. These antidepressants generally cause fewer bothersome side effects and are less likely to cause problems at higher therapeutic doses than other types of antidepressants.” The most common side effects of SSRIs are:

• Agitation or nervousness
• Dizziness
• Headache
• Insomnia or drowsiness
• Nausea, diarrhea or constipation
• Sexual dysfunction, such as decreased libido or difficulty achieving orgasm

Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)

SNRIs include medications like venlafaxine (Effexor), duloxetine (Cymbalta) and desvenlafaxine (Pristiq). The most common side effects are similar to those from SSRIs, plus:

• Dry mouth
• Elevated blood pressure or heart rate
• Increased sweating

Tricyclic Antidepressants (TCAs)

Tricyclic antidepressants are older medications such as imipramine (Tofranil), nortriptyline (Pamelor), amitriptyline [Elavil], doxepin and desipramine (Norpramin) that work by increasing the levels of certain neurotransmitters in the brain, such as serotonin and norepinephrine. The most common side effects for TCAs include:

• Blurred vision
• Constipation
• Dizziness
• Drowsiness
• Dry mouth
• Increased heart rate
• Urinary retention
• Weight gain

Monoamine Oxidase Inhibitors (MAOIs)

MAOIs comprise a class of antidepressant medications that work by inhibiting the enzyme monoamine oxidase (MAO) which is responsible for breaking down neurotransmitters, including serotonin, norepinephrine, and dopamine. By inhibiting MAO, MAOIs increase the levels of these neurotransmitters in the brain, which can improve mood and reduce symptoms of depression.

MAOIs include medications such as phenelzine (Nardil), tranylcypromine (Parnate) and isocarboxazid (Marplan). As the National Alliance on Mental Illness (NAMI) website explains, “MAOIs are the least-prescribed of all antidepressants because they can cause dangerously high blood pressure when combined with certain foods or medications. People taking MAOIs must watch their diets carefully to avoid potentially life-threatening complications. Off-limits foods typically include aged cheese, sauerkraut, cured meats, draft beer and fermented soy products such as miso, tofu or soy sauce. Some people may have to avoid wine and all forms of beer.” The most common side effects of MAOIs are:

• Insomnia
• Muscle cramps
• Postural hypotension, a sudden drop in blood pressure when standing up
• Sexual dysfunction
• Significant dietary restrictions in order to avoid dangerous interactions
• Weight gain

Atypical Antidepressants

Your clinician may also prescribe other antidepressants that do not fit clearly into the above classes:

Bupropion (Wellbutrin) may cause insomnia, headache, dry mouth, nausea and agitation. It is known for being less likely to cause sexual side effects.

Mirtazapine (Remeron) may cause increased appetite, weight gain and drowsiness.

Trazodone (Desyrel) may cause drowsiness, dizziness, dry mouth, and in rare but serious cases, persistent erection.

Normal vs. Concerning Symptoms

Many antidepressant side effects are mild and temporary. You may experience mild nausea, temporary headache or slight drowsiness as your body gets used to your new medication. However, if these symptoms are significantly impacting your life or don’t get better after a few weeks, you should tell your clinician.

You should also contact your clinician right away if you notice any of the following concerns.

• Allergic reaction symptoms such as rash, itching, swelling or difficulty breathing
• Manic symptoms such as racing thoughts, impulsivity or a decreased need for sleep
• Seizures
• Significant changes in blood pressure
• Unexplained bleeding or bruising

Be sure to discuss any other medications you are taking with your clinician before you start. The National Institute of Mental Health (NIMH) website describes that these interactions can cause serious side effects in some cases. “Combining antidepressants with other medications or supplements that act on the serotonin system, such as triptans (often used to treat migraine headaches) and St. John’s wort (a dietary supplement), can cause a rare but life-threatening illness called serotonin syndrome. Symptoms of serotonin syndrome include agitation, muscle twitches, hallucinations (seeing or hearing things others do not see or hear), high temperature, and unusual blood pressure changes. For most people, the risk of such extreme reactions is low. It is important for health care providers to consider all possible interactions and use extra care in prescribing and monitoring medication combinations that have an above-average risk.”

If you experience suicidal thoughts or worsening depression while taking your antidepressant, tell your clinician immediately. This is always a serious concern and requires urgent medical attention.

Managing Side Effects

Being open and honest with your clinician during this process can allow you to better manage any side effects that you feel. Together, you can make tweaks to your treatment plan that can make a big difference in your experience. The GeneSight test could be a valuable addition to your clinician’s toolbox.

• Dose or timing adjustments: Sometimes lowering the dose of your medication or taking it at a different time of day can reduce its side effects. For example, if your antidepressant makes you drowsy, your provider may recommend that you try taking it at night.
• Lifestyle changes: Making changes to your diet, exercise, and sleep habits may help manage side effects for some people.
• Switching medications: If your antidepressant isn’t working for you after a period of time, your clinician may recommend trying a different type of medication.
• Adding another medication: If your antidepressant seems to be working but you are having a specific side effect, adding another medication may help. For example, if you’re expecting sexual dysfunction, your clinician may be able to prescribe a medication to help .

Finding More Information

Learning more about the potential side effects of medication treatment helps you set the right expectations for what may happen next and can empower you on your mental health journey. For many people, the benefits of effective medication treatment outweigh the risks of side effects over time.

You should consider you and your clinician on the same team, with the same goals. Talk to your clinician or your pharmacist if you have concerns about side effects. And if you feel like your medication isn’t working, don’t stop taking it without talking to your clinician first. Together, you can find the right answers to help you continue to move forward.

For more information on taking antidepressants, visit:

• The National Alliance on Mental Illness (NAMI).
• The National Institute of Mental Health (NIMH).