As with other drugs, Cymbalta (duloxetine) can cause side effects, such as dry mouth, nausea, and sexual side effects. If you are not able to tolerate side effects of Cymbalta, talk with your doctor or pharmacist.

Cymbalta (duloxetine) is a brand-name delayed-release oral capsule that the Food and Drug Administration (FDA) has approved to treat the following conditions in adults:

The drug is also approved to treat the following conditions in certain children:

  • GAD in children ages 7 years and older
  • fibromyalgia in children ages 13 years and older

Cymbalta belongs to the serotonin-norepinephrine reuptake inhibitor (SNRI) drug class.

If you have problems with side effects from Cymbalta, talk with your doctor or pharmacist. They can discuss ways to manage side effects or other available treatment options. Do not stop taking Cymbalta without consulting your doctor first.

For additional information about Cymbalta, including details about its uses, see this Cymbalta overview article.

Cymbalta has a boxed warning. A boxed warning is the most serious warning from the FDA. For details, see the “Boxed warning for Cymbalta” section.

Cymbalta can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist. How long side effects of Cymbalta last depends on several factors, including how your body responds to the drug.

These are just a few of the more common side effects reported by people who took Cymbalta in clinical trials:

For more information about some of these side effects, see “Side effect specifics.”

Mild side effects can occur with Cymbalta use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Cymbalta’s prescribing information.

Mild side effects that have been reported with Cymbalta include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

For more information about some of these side effects, see the “Side effect specifics” section.

Note: After the FDA approves a drug, it tracks side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking Cymbalta and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Cymbalta may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Cymbalta’s prescribing information.

If you develop serious side effects while taking Cymbalta, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

Allergic reaction

For some people, Cymbalta can cause an allergic reaction. But it’s not clear whether this side effect occurred in the drug’s clinical trials.

In general, symptoms of allergic reaction can be mild or serious.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Cymbalta, your doctor may recommend taking a different medication instead.

Cymbalta is approved to treat generalized anxiety disorder in children ages 7 years and older. It’s also approved to treat fibromyalgia in children ages 13 years and older. The list below may not include all possible side effects of Cymbalta in children. For more information, see Cymbalta’s prescribing information.

In clinical trials of Cymbalta, the following side effects were commonly reported in children:

  • loss of appetite
  • decreased weight
  • diarrhea
  • fatigue
  • vomiting
  • nausea (see “Side effect specifics”)

In addition, Cymbalta has a boxed warning for the risk of suicidal thoughts and behaviors in children. For more information, see “Boxed warning for Cymbalta.”

If you have questions about Cymbalta and its possible side effects in children, speak with your child’s doctor or pharmacist.

Cymbalta has a boxed warning for the risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the FDA.

Antidepressants, such as Cymbalta, can increase the risk of suicidal thoughts and behaviors in people with depression and other mental health conditions. Cymbalta may increase this risk in children, adolescents, and young adults up to 24 years old.

In clinical trials, this increased risk was not reported in adults older than 24 years. The risk of suicidal thoughts and behaviors may actually be lower in adults 65 years and older.

What you can do

Due to the boxed warning, doctors typically monitor closely for signs of suicidal thoughts or behaviors. Signs to watch for include changes in thoughts, feelings, mood, or behavior. If you notice any of these symptoms, contact your doctor immediately.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

  • Call or text the 988 Lifeline at 988 or chat at 988lifeline.org. Caring counselors are available to listen and provide free and confidential support 24/7.
  • Text HOME to the Crisis Text Line at 741741 to connect with a volunteer crisis counselor for free and confidential support 24/7.
  • Not in the United States? Find a helpline in your country with Befrienders Worldwide.
  • Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you’re not in the same household, stay on the phone with them until help arrives.

Cymbalta may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Is weight gain a side effect of Cymbalta?

No, weight gain wasn’t reported in Cymbalta’s clinical trials. However, weight gain can result from depression or inactivity due to other chronic medical conditions.

Cymbalta treats depression and other conditions that can result in inactivity due to pain or fatigue, such as fibromyalgia and diabetic neuropathy (nerve pain). So, it’s important to discuss weight changes with your doctor.

If you have concerns about weight gain with Cymbalta, talk with your doctor. They can help determine potential causes and ways to manage it.

If I stop taking Cymbalta, will I experience withdrawal symptoms?

Stopping Cymbalta treatment may cause a group of withdrawal symptoms called discontinuation syndrome.

Discontinuation syndrome can happen any time you stop taking an antidepressant. However, it’s more likely when you stop it suddenly. Due to this risk, doctors typically do not recommend stopping Cymbalta abruptly. Instead, doctors usually recommend gradually reducing the dose of the drug.

Talk with your doctor if you’re interested in stopping treatment with Cymbalta. Do not stop taking the drug before talking with your doctor about how to do so safely. When stopping treatment, report any unusual symptoms to your doctor, such as burning or tingling, dizziness, or shock-like sensations in your brain (brain zaps).

Learn more about Cymbalta withdrawal and how you and your doctor can manage it.

Can Cymbalta cause long-term side effects?

It’s possible. Some serious side effects of Cymbalta, such as liver damage and angle-closure glaucoma, may be long term. Contact your doctor right away if you experience any serious side effects.

Most mild side effects of Cymbalta are temporary, lasting a few days to weeks. But, be sure to talk with your doctor or pharmacist if side effects last longer, bother you, or become severe.

Does Cymbalta cause different side effects in women vs. men?

In clinical trials of Cymbalta, males* and females* reported some differences in side effects.

Certain sexual side effects were reported in both males and females, including decreased sexual desire and a delay or lack of orgasm. However, males also reported erectile dysfunction (ED) and delayed ejaculation. Additionally, sexual side effects were more common in males than in females.

For more information about sexual side effects with Cymbalta, view the “Serious side effects” section.

If you have questions or concerns about Cymbalta’s side effects, talk with your doctor or pharmacist.

* Sex and gender exist on spectrums. Use of the terms “female” and “male” in this article refers to sex assigned at birth.

Is Cymbalta safe for older adults?

Yes, Cymbalta is considered safe for older adults (ages 65 years and older) to take. Overall, Cymbalta side effects were similar among adults over and under the age of 65 years who took the drug in clinical trials.

That said, people over age 65 years may be more sensitive to some of the drug’s side effects, such as low sodium levels and orthostatic hypotension, which can increase the risk of falls.

If you have questions about the safety of Cymbalta given your age, talk with your doctor or pharmacist.

Learn more about some of the side effects that Cymbalta may cause. To find out how often side effects occurred in clinical trials, see Cymbalta’s prescribing information.

Sexual side effects

Cymbalta may cause sexual side effects in some people. These can include ED, delayed ejaculation, a delay or lack of orgasm, and decreased libido.

However, it’s important to know that some of the conditions Cymbalta treats can also cause sexual dysfunction. This can make it hard to tell whether it’s the condition or the drug causing the side effect.

In clinical trials of Cymbalta, males* taking Cymbalta reported more sexual side effects than those taking a placebo. (In these studies, a placebo was a pill without an active ingredient.) In females,* the same sexual side effects occurred with both Cymbalta and the placebo.

What you can do

If you have questions or concerns about sexual side effects, talk with your doctor. Tell your doctor about any changes in sexual function during treatment with Cymbalta. They can suggest ways to manage or treat these concerns.

* Sex and gender exist on spectrums. Use of the terms “female” and “male” in this article refers to sex assigned at birth.

Nausea

Nausea was the most common side effect reported in clinical trials of Cymbalta. It was also the most common reason people stopped taking the drug.

It’s important to let your doctor know about any nausea you experience. This can be a symptom of other serious side effects, such as serotonin syndrome (too much serotonin in the body) and withdrawal symptoms. (For details, see the question, “If I stop taking Cymbalta, will I experience withdrawal symptoms?”)

What you can do

Contact your doctor if you have nausea that persists or becomes severe. They can help you find ways to manage this side effect.

Tips to help relieve nausea include:

  • avoiding fatty, fried, greasy, spicy, or heavily seasoned foods
  • consuming several small snacks during the day instead of three large meals
  • avoiding strong aromas and smells
  • taking sips of liquid or sucking on ice chips often during the day

Headache

Headache was another common side effect reported in clinical trials of Cymbalta. However, this side effect occurred only slightly more in people taking Cymbalta. So, it’s difficult to tell whether or not Cymbalta caused these headaches.

That said, headache can be a symptom of other serious side effects, such as angle-closure glaucoma and discontinuation syndrome. (For details about this syndrome, see the question, “If I stop taking Cymbalta, will I experience withdrawal symptoms?”)

What you can do

Contact your doctor if you have headaches that persist or become severe. They can suggest ways to manage this problem, such as taking over-the-counter (OTC) pain relievers. These pain relievers can include ibuprofen (Advil) or naproxen (Aleve). For a severe headache with other symptoms that concern you, seek medical care right away.

Constipation

Constipation was also a common side effect reported in Cymbalta’s clinical trials. However, it wasn’t one of the reported reasons that people stopped taking the drug.

What you can do

Contact your doctor if constipation becomes long lasting or severe. They can recommend ways to manage this side effect, including certain OTC remedies. They may suggest a stool softener, such as docusate (Colace), or a laxative, such as bisacodyl (Dulcolax).

Tips to help relieve and prevent constipation include:

Take note of the following important information to consider before taking Cymbalta.

Cymbalta has a boxed warning for the risk of suicidal thoughts and behaviors. This is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Boxed warning for Cymbalta” section above.

Other precautions

Be sure to talk with your doctor about your health history before you take Cymbalta. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These are considered drug-condition or drug-factor interactions. The conditions and factors to consider include:

Activation of mania: Cymbalta may trigger a manic or hypomanic episode in people with depression. Symptoms of these episodes may include euphoria, irritability, or racing thoughts. The risk may be higher if you have bipolar disorder or risk factors for the condition. Tell your doctor if you have a history of bipolar disorder before starting Cymbalta. They can advise whether this medication is safe for your condition.

Bleeding problems: Cymbalta can increase the risk of bleeding. This risk may be higher if you take other drugs that affect bleeding, such as aspirin, warfarin, or other anticoagulants. Certain clotting disorders can also increase your risk of this side effect. If you take any of these drugs or have a history of clotting disorders, talk with your doctor before starting Cymbalta. They can advise whether this medication is safe for your condition.

Diabetes: In people with diabetes, Cymbalta can make it harder to manage blood sugar levels. If you have diabetes, tell your doctor before starting Cymbalta. They can suggest any necessary changes in how you monitor your blood sugar or manage your diabetes.

High blood pressure: Cymbalta may cause increases in blood pressure. Your doctor will check your blood pressure before prescribing the drug and during treatment. If you already have high blood pressure, taking Cymbalta may worsen this condition. In this case, your doctor will likely want to treat your high blood pressure before prescribing Cymbalta.

Your doctor may also recommend that you check your blood pressure at home between appointments. If you develop high blood pressure while taking Cymbalta, let your doctor know. They can advise whether this treatment is still safe for your condition.

Liver or kidney problems: Cymbalta isn’t recommended for people with severe liver or kidney problems, such as liver disease or kidney disease. Taking this drug may worsen these conditions. If you have liver or kidney problems, talk with your doctor before starting Cymbalta. They may recommend other treatment options for your condition.

Seizure: Cymbalta may cause seizure as a side effect, but the drug hasn’t been studied in people with seizure disorders. Because of this, it’s not known if the drug is safe for people with these conditions to take. If you have a seizure disorder or history of seizures, tell your doctor before starting Cymbalta. They may recommend other treatment options for your condition.

Slow stomach emptying: Cymbalta has a coating that protects it from stomach acid. When the stomach empties slowly, the stomach acid can break down this coating. This may cause Cymbalta to be less effective. If you have diabetes or another condition that could affect stomach emptying, tell your doctor before starting Cymbalta.

Allergic reaction: If you’ve had an allergic reaction to Cymbalta or any of its ingredients, your doctor will likely not prescribe Cymbalta. Ask your doctor what other medications may be better options for you.

Pregnancy and breastfeeding: Cymbalta may cause harm to a developing fetus. However, more research is necessary to determine if there is a clear risk of congenital anomalies (commonly known as birth defects). Cymbalta passes into human breast milk and can affect a child who is breastfeeding. However, it isn’t known to cause serious side effects. For more information and guidance about these topics, see how Cymbalta affects pregnancy and breastfeeding.

Alcohol consumption: Cymbalta and heavy alcohol consumption may interact and cause severe liver damage. Your doctor will likely recommend avoiding heavy alcohol consumption while taking Cymbalta. If you have questions about alcohol and Cymbalta, talk with your doctor.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.