Cymbalta (Duloxetine) Side Effects: Common, Severe, & Long-Term

What Is Cymbalta (Duloxetine)?

Cymbalta, the brand name for its active ingredient duloxetine, is an FDA-approved antidepressant used to treat symptoms of depression, anxiety, and other conditions. The antidepressant belongs to the selective serotonin and norepinephrine reuptake inhibitors (SNRIs) class of drugs that works by increasing amounts of serotonin and norepinephrine in the brain.¹

Cymbalta is used to improve and manage major depressive disorder (MDD) and generalized anxiety disorder (GAD). The antidepressant regulates serotonin and norepinephrine levels in the brain, increasing one’s mood, focus, and energy. While Cymbalta does not cure depression or anxiety, it does help reduce unwanted symptoms that accompany these conditions.

Side Effects of Cymbalta

Like other SSRIs or SNRIs, Cymbalta can cause side effects in users, such as changes in appetite and sleep quality. This is particularly true in the initial stage of treatment. Common side effects likely will not require immediate medical assistance. However, they may become severe and possibly life-threatening.¹

How one reacts to Cymbalta depends on several factors, including their age, their overall health condition, and how the drug interacts with their body. After beginning a Cymbalta prescription, symptom improvement should be noticeable after two to four weeks of treatment.²You should not stop taking Cymbalta abruptly if you do not experience relief, as it may take additional time to show improvement.

Common Side Effects

Side effects of Cymbalta are generally mild as one adjusts to their medication. These side effects typically include nausea, headache, fatigue, dizziness, and vomiting. These reactions do not generally require medical attention, as they commonly last only a few weeks following the initial dosage.

Common side effects of Cymbalta may include:¹

• Nausea
• Insomnia
• Tiredness
• Constipation
• Dry mouth
• Changes in appetite
• Diarrhea
• Sweating
• Intestinal problems
• Sexual dysfunction
• Weight gain
• Sweating
• Dizziness
• Agitation

Severe Side Effects

Although Cymbalta has undergone rigorous testing to ensure the efficacy of the medication, it is still possible to have severe side effects. These may require immediate medical attention to prevent further harm to the consumer. The severity of Cymbalta side effects is greatly influenced by a person’s health condition, genetic profile, age, and how the drug reacts with their body.

Severe side effects of Cymbalta that may require immediate medical attention can include:^{1, 3}

• Suicidal ideation
• Low blood pressure that can lead to dizziness and falls
• Vision problems
• Manic episodes in people who have bipolar disorder
• Discontinuation syndrome
• Hyponatremia

Rare Side Effects

In extreme cases, Cymbalta can lead to serious and life-threatening side effects. While these reactions are not common, it is important to be aware of potential risks while taking any prescription medication.

Rare side effects of Cymbalta may include:

• Bleeding problems
• Severe skin reactions such as Stevens Johnson Syndrome
• Serotonin syndrome
• Liver toxicity that can lead to liver problems or failure
• Heart palpitations
• Long-Term Side Effects

Using Cymbalta for an extended period can lead to long-term complications, including dependency and liver damage. This is mainly attributed to the drug altering the physiology of the body. As the body adapts to Cymbalta, possible discontinuation of the medication can be dangerous.

Long-term side effects of Cymbalta may include:^{1, 4}

• Dependence
• Liver damage
• Coronary heart disease

Allergic Reactions to Cymbalta

You should talk with your doctor if you have a history of experiencing allergic reactions to antidepressants. Adverse reactions to Cymbalta can worsen and require immediate medical attention. Your doctor can prescribe a more suitable alternative should you need it.

Severe allergic reactions to Cymbalta may include:¹

Breathing problems

• Blisters
• Mouth sores
• Anaphylaxis
• Swelling
• Increased sweating
• Vomiting
• Nausea

Interactions With Cymbalta

Taking certain medications, herbs, or supplements alongside Duloxetine can change how Duloxetine works in your body or increase the risk for serious side effects. This article does not consider all the possible interactions. Please let your doctor, psychiatrists, and pharmacists know about all the products you currently use, such as prescription medication, nonprescription drugs, and herbal supplements. Do not start, stop, or change the dosage of any medicines without your doctor’s approval.

Duloxetine, the active ingredient in Cymbalta, can interact negatively with other substances. Therefore, mixing it with substances such as alcohol, other medications, or dietary supplements can pose great health concerns. Consult with your doctor before considering any other substances while taking Cymbalta.

Substances that can negatively interact with Cymbalta include:¹

• Monoamine oxidase inhibitors (MAOIs): Taking Cymbalta within 14 days of stopping MAOIs medication increases the risk of serotonin syndrome.
• Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Mixing Cymbalta with NSAIDs such as ibuprofen and aspirin increases the risk of bleeding.
• Other SNRIs: Mixing Cymbalta with other SNRIs medication may worsen the side effects of either substance.
• Benzodiazepines: Combining Cymbalta with benzodiazepines can worsen side effects such as sleepiness and dizziness.
• Blood thinners: Using blood thinners while taking Cymbalta can result in bleeding episodes, especially in those with bleeding disorders.
• Antiarrhythmic drugs: Taking an antiarrhythmic drug such as quinidine can raise the level of Cymbalta in your body. This can worsen the side effects of Cymbalta and the antiarrhythmic.
• Alcohol: Combining Cymbalta and alcohol can worsen the side effects of either substance.
• Opioids: When mixed with Cymbalta, opioids may increase the risk of serotonin toxicity in the body.
• Muscle relaxers: Taking both Cymbalta with muscle relaxers increases the risk of serotonin syndrome, increased heart rate, and seizures.

Who Experiences Side Effects More?

Cymbalta medication will produce various side effects from person to person. Seniors, pregnant or breastfeeding people, and pediatric patients below seven years should not take Cymbalta without the guidance of a doctor.

Side Effects in Women

The risk of Cymbalta in pregnant individuals is not fully known. Some data shows that taking Cymbalta the month before giving birth increases the risk of postpartum hemorrhage. However, it is also known that individuals who stop taking Cymbalta during pregnancy are more likely to have a relapse of their depression and this can be dangerous for them. Babies exposed to Cymbalta have had complications that required extended hospital stays after birth. It’s important to talk with your doctor about the risks and benefits of taking Cymbalta during pregnancy or breastfeeding.

Side Effects in Children

Children should take their Cymbalta medication under the guidance of a doctor, as this drug increases the risks of suicidal ideation and impulsive behaviors. In some children, Cymbalta may also trigger anxiety, agitation, or hostility. These effects may be a clear indication that the child’s depression is worsening. Before a child starts taking antidepressant medication, consult with your physician to understand the risks.⁶

Withdrawal Symptoms from Cymbalta

Long-term use of Cymbalta can lead to dependency. Suddenly discontinuing your medication without proper guidance puts you at risk for experiencing withdrawal symptoms. These symptoms include persistent headaches and increased sweating. If you feel you are suffering from Cymbalta withdrawal, seek professional help from your doctor.⁶

Questions to Ask Your Health Team

When considering Cymbalta for your depression or anxiety, consult with your doctor to understand the risks associated with the drug first. Your doctor can help you determine if Cymbalta is a good fit for you, or if another alternative may be appropriate.

Questions to ask your care team when considering Cymbalta include:

• How long will it take for me to adjust to my Cymbalta prescription?
• Am I at risk for severe symptoms if I am already taking other anxiety/depression medications?
• Will a previous history of addiction make me more susceptible to dependency?
• What is the best dosage to ensure the least side effects?
• Are there substances I am currently taking that can interact with Cymbalta?
• When should I reach out to you about side effects?
• Is there anything I should tell my therapist about this new medication?
• Is it possible to change my medication if Cymbalta doesn’t work for me?

Final Thoughts

Cymbalta medication can result in side effects that may or may not require immediate medical assistance. However, should these reactions become severe, you should seek immediate medical help. Before taking Cymbalta, talk with your doctor to understand any associated risks. Some populations, especially pregnant and breastfeeding women, pediatric patients, and seniors are at an increased risk for experiencing potential side effects.