Cymbalta Side Effects: What They Are And How To Manage Them

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HealthlineSubscribeCymbalta Side Effects and Tips for Managing Them

Medically reviewed by Alexandra Perez, PharmD, MBA, BCGP — Written by Patricia Weiser, PharmD — Updated on July 22, 2025

More common side effects
Mild side effects
Serious side effects
Side effects in children
Sexual side effects
Long-term side effects
FAQ
Boxed warning for Cymbalta
Managing side effects
Warnings
Q&A

Key takeaways

Cymbalta (duloxetine) is a brand-name drug used to treat certain conditions, including depression. The drug can cause side effects that range from mild to serious, including some sexual side effects.
Mild side effects of Cymbalta include drowsiness, nausea, and sexual side effects like low libido. These are usually manageable and may go away on their own with time.
Cymbalta may also cause severe side effects. These include liver damage, eye problems, and suicidal thoughts and behaviors. It’s possible, but uncommon, for these to be long-term effects.

Cymbalta is used as a long-term treatment for several conditions in adults, including:

major depressive disorder
generalized anxiety disorder (GAD)
pain caused by diabetic neuropathy (nerve damage caused by diabetes)
fibromyalgia (a condition that causes pain throughout the body)
long-term musculoskeletal pain (pain in the bones, muscles, tendons, ligaments, and nerves)

Cymbalta is also approved to treat GAD and fibromyalgia in certain children.

The active ingredient in Cymbalta is duloxetine. (An active ingredient is what makes a drug work.) The drug comes as capsules that you swallow.

Keep reading to learn about the common, mild, and serious side effects that Cymbalta can cause. For a general overview of the drug, including details about its uses, see this article.

Cymbalta has a boxed warning. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Boxed warning for Cymbalta” section.

More common side effects of Cymbalta

Cymbalta can cause certain side effects, some more common than others. These side effects may be temporary, lasting a few days to weeks. Talk with your doctor if side effects do not go away, get worse, or become too difficult to tolerate.

Cymbalta’s commonly reported side effects include:

fatigue (lack of energy)
nausea
constipation
reduced appetite
sweating more than usual (see “Tips for managing side effects”)
dizziness

The use of binary terms such as “male” and “female” or “men” and “women” in this article reflects the language of the sources we’ve used. Unless otherwise noted, it’s unclear whether the research we reference included participants with expansive gender identities.

Mild side effects of Cymbalta

Mild side effects have been reported with Cymbalta. These include:

sleepiness
fatigue (lack of energy)
nausea
dry mouth
constipation
reduced appetite
dizziness
headache
sexual side effects in females and males
sweating more than usual
trouble sleeping
headache
belly pain

In most cases, these side effects should be temporary. Some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop using Cymbalta unless your doctor recommends it.

Cymbalta may cause mild side effects other than those listed. See Cymbalta’s prescribing information for details.

For more information about some of these side effects, see “Tips for managing side effects.”

Serious side effects of Cymbalta

Cymbalta may cause serious side effects. The following list 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 with Cymbalta include:

suicidal behaviors and thoughts (see “Boxed warning for Cymbalta”)
liver damage (see “Tips for managing side effects”)
eye problems (see “Tips for managing side effects”)
fainting or dizziness when standing up
blood pressure changes
serotonin syndrome, a rare side effect of drugs that affect serotonin, a brain chemical
low sodium levels
urination problems
severe skin reaction, such as Stevens-Johnson syndrome
unusual bleeding or bruising

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medication 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.

Allergic reaction
For some people, Cymbalta can cause an allergic reaction. But this side effect wasn’t reported in the drug’s studies.In general, symptoms of an allergic reaction can be mild or serious.What might help
If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should continue Cymbalta treatment.
If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.
If your doctor confirms you’ve had a serious allergic reaction to Cymbalta, they may have you switch to a different treatment.

Side effects in children

The most common side effects of Cymbalta in children may include:

weight loss
reduced appetite
fatigue (lack of energy)
nausea or vomiting
diarrhea

Sexual side effects in women and men

Sexual side effects from taking Cymbalta are possible and may be more common in males than females. In studies, sexual side effects were reported in a small percentage of males and females during Cymbalta treatment. Some of these side effects, such as erectile dysfunction, may be more likely to occur when taking a higher dosage of Cymbalta.

Males who took Cymbalta reported significantly more sexual side effects compared with those who took a placebo (a treatment that contains no active drug). The sexual side effects reported in males included:

decrease in or loss of libido (sex drive)
difficulty becoming aroused
erectile dysfunction
difficulty reaching orgasm
delayed ejaculation or being unable to ejaculate

Females who took Cymbalta also reported sexual side effects. But these side effects were similar to those experienced by females who received a placebo. Sexual side effects included:

decreased libido (sex drive)
difficulty becoming aroused
reduced vaginal lubrication
difficulty reaching orgasm

Some males and females in this study reported improvements in sexual desire, performance, and satisfaction with Cymbalta treatment. This may be because the medication helped to reduce the symptoms of their condition. As a result, their sexual health may have also improved.

Long-term side effects of Cymbalta

Some side effects of Cymbalta can affect your long-term health, but this isn’t common.

For example, liver failure is a rare but serious side effect of Cymbalta. Heavy alcohol use may increase the risk of liver failure. The liver damage that develops from this side effect doesn’t go away once a person stops taking Cymbalta.

You may be wondering if it’s safe to take Cymbalta long term. Studies have tested the drug’s safety for up to 6 months. A 2009 study has shown Cymbalta to be safe to use when taken for 12 months. Your doctor can tell you about their understanding of long-term Cymbalta use.

It’s a good idea to go over all of your medications with your doctor every so often. Together, you can discuss your condition and consider whether you should continue Cymbalta long term.

FAQ about Cymbalta’s side effects

Keep reading to get answers to some frequently asked questions about Cymbalta’s side effects.

How long do Cymbalta’s side effects last?

How long side effects from Cymbalta last can vary. Some of the more common side effects are usually temporary, such as sleepiness, dizziness, and reduced appetite. These side effects typically ease within a few days or weeks after starting treatment.

Common side effects may get worse after your doctor increases your dosage, but this is usually temporary.

Other side effects are more likely to continue for as long as you’re taking the drug. Examples include sweating more than usual and sexual side effects. These side effects usually aren’t severe.

Cymbalta side effects can affect each person differently. For example, nausea may be a mild, temporary side effect for some people. For others it can be bothersome. In studies, a small percentage of people had to stop taking the drug due to nausea.

If you’re experiencing troublesome side effects, you should not suddenly stop taking Cymbalta. It’s best to talk with your doctor first. If you and your doctor decide that you should stop the drug, they’ll guide you on how best to do so.

Do older adults have a higher risk for side effects from Cymbalta?

No, this doesn’t seem to be the case. In general, older adults (ages 65 years and older) have a higher risk for medication side effects compared with younger adults. But in studies of Cymbalta, older adults had similar side effects to those of younger adults.

Can Cymbalta cause weight gain?

Cymbalta doesn’t typically cause weight gain. In studies, weight gain wasn’t reported as a side effect.

In fact, weight loss is more likely than weight gain with Cymbalta. This is because the drug commonly causes reduced appetite and nausea.

These side effects may lead to weight loss, especially in children. Because of this, if your child is taking Cymbalta, their doctor will monitor your child’s weight and height during Cymbalta treatment.

If you have questions about weight changes with Cymbalta, talk with your doctor.

Will Cymbalta side effects differ depending on the strength I use (20 mg, 30 mg, or 60 mg)?

Some side effects of Cymbalta may be dependent on dose. Cymbalta comes in the following strengths: 20 milligrams (mg), 30 mg, and 60 mg. A higher strength of the drug might come with a higher risk of certain side effects.

Common dose-dependent side effects of Cymbalta include nausea, fatigue (lack of energy), constipation, dizziness, reduced appetite, and sweating more than usual.

Boxed warning for Cymbalta

Cymbalta has a boxed warning for suicidal behaviors and thoughts. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Antidepressants such as Cymbalta may increase the risk of suicidal behaviors and thoughts in children and young adults ages 24 years or younger. This is a rare side effect. Studies show that the risk is higher after a person first starts treatment or increases their dose.

What might help

While taking Cymbalta, you should watch for any new behaviors, feelings, or thoughts. This is especially important in the first few weeks after starting Cymbalta or after your dose is adjusted.

Consider using a journal or app to make notes about your mood. You may want to ask your loved ones to let you know if they notice that you’re acting differently. Tell your doctor right away if you or someone else notices any changes in your behavior or mood.

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 Suicide and Crisis 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.

Tips for managing side effects

There may be things you can do to help make certain Cymbalta side effects more manageable. If you have ongoing, worsening, or bothersome side effects, talk with your doctor or pharmacist. They can suggest tips for managing them or recommend other available treatment options for your condition.

Sweating more than usual

Sweating more than usual is a common side effect of Cymbalta. This side effect may be worse with higher doses of the drug. In addition, hot flashes (also called hot flushes) are a possible side effect of this medication.

Some people may notice increased sweating only in certain situations, such as when they’re active or during humid weather. Others may have increased sweating more often, including while trying to sleep.

What might help

Increased sweating isn’t a harmful side effect, but it may be uncomfortable. Here are a few tips that may help ease this side effect:

Try swapping deodorant for an antiperspirant.
Take regular showers.
Wear light fabrics
Try using a fan at night.

If this side effect continues to bother you, your doctor may suggest adjusting your dosage or switching to a different drug.

But if Cymbalta is particularly effective for your condition, you may not want to switch to a different drug. In this case, your doctor may suggest treatments for your sweating. Examples of drugs sometimes used to treat this side effect include:

benztropine (Cogentin)
cyproheptadine
terazosin

If you have concerns about sweating more than usual with Cymbalta, talk with your doctor.

Eye problems

Eye problems aren’t a common side effect of Cymbalta. But this drug may increase the risk of serious eye problems, such as glaucoma (a buildup of pressure within the eye).

Cymbalta can cause a person’s pupils to dilate. This can trigger a serious eye problem, including vision loss, especially for someone who has closed-angle glaucoma. Symptoms can include:

sudden vision changes
eye pain
eye redness
swelling in or around your eye

What might help

If you have closed-angle glaucoma, you should not take Cymbalta. If you’re not sure whether you have this condition, consider visiting an eye doctor. The results of an eye exam can help you and your doctor decide if it’s safe for you to take Cymbalta.

If you develop any of these symptoms while taking Cymbalta, you should seek medical attention. Urgent treatment is needed to help prevent permanent vision loss.

If you have questions about eye problems that Cymbalta may cause, talk with your doctor.

Liver damage

Although rare, Cymbalta can cause serious liver damage that could be fatal. The risk of this side effect may be higher with alcohol use. It could also be higher in people who already had liver problems before starting Cymbalta.

The following may indicate that there’s a problem with your liver:

pain in the upper right part of your belly
itching
dark urine
yellowing of your skin or whites of your eyes
increased liver enzyme levels

What might help

To help prevent this side effect, talk with your doctor about any liver problems you’ve had. It’s also important to be honest about your alcohol consumption. Talk with your doctor about whether you’ve had problems with your liver or alcohol in the past.

If you develop any of these symptoms, get emergency medical care right away.

Trouble sleeping

Insomnia (trouble falling asleep or staying asleep) can occur with Cymbalta. In studies, this side effect was more commonly reported in people taking the drug for long-term musculoskeletal pain. (This is pain in the bones, muscles, tendons, ligaments, and nerves.) Waking up earlier than desired was also reported with Cymbalta.

Insomnia is also a common side effect reported in children taking Cymbalta.

What might help

Here are a few tips that may help to improve your sleep:

Try to exercise regularly.
Avoid caffeine after lunch.
Practice good sleep hygiene.

If you’re having insomnia since starting Cymbalta, talk with your doctor. They may suggest the temporary use of a sleep aid, such as melatonin. Or they may adjust your dosage or discuss other treatment options with you.

Keeping track of side effects
During Cymbalta treatment, consider keeping notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.
Your side effect notes can include things such as:
what dose of drug you were taking when you had the side effect
how soon after starting that dose you had the side effect
what your symptoms were from the side effect
how it affected your daily activities
what other medications you were also taking
any other information you feel is important
Keeping notes and sharing them with your doctor will help your doctor learn more about how Cymbalta affects you. Your doctor can use this information to adjust your treatment plan if needed.

Warnings for Cymbalta

Consider the following important information before starting Cymbalta.

Cymbalta has a boxed warning. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Boxed warning for Cymbalta” section.

Other warnings

Before taking Cymbalta, discuss your health history with your doctor. Cymbalta may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

liver or kidney problems
closed-angle glaucoma
high blood pressure or heart problems
slow stomach emptying
diabetes
seizures
bipolar disorder or mania
low sodium levels
bleeding problems
previous allergic reaction to this or a similar drug
pregnancy
breastfeeding
alcohol consumption

Ask a pharmacist

Q:

My child has generalized anxiety disorder, and their doctor suggested Cymbalta treatment. I’m concerned about the drug’s suicide warning. How common or rare is this side effect, and how can it be avoided?

Anonymous patient

A:

The risk of suicidal behaviors and thoughts with Cymbalta use is rare. But Cymbalta does have a boxed warning for this side effect. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

When compared with a placebo (a treatment with no active drug), antidepressants such as Cymbalta were associated with increased suicidal behaviors and thoughts. This risk affected children and young adults ages 24 years and younger.

For more about this FDA boxed warning, see the “Side effects explained” section.

If your child’s doctor prescribes Cymbalta, make sure to monitor your child for any changes in their behavior or mood. This is especially important when treatment with Cymbalta begins or the dosage is changed. Contact your child’s doctor right away if you notice any changes in your child’s behavior or mood.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline 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.

How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Choy EHS, et al. (2009). Safety and tolerability of duloxetine in the treatment of patients with fibromyalgia: Pooled analysis of data from five clinical trials.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2721139/
Cymbalta (duloxetine delayed-release capsules), for oral use. (2023).https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/021427s055s057lbl.pdf
Kolli V, et al. (2013). Improvement of antidepressant-induced sweating with as-required benztropine.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3931183/
Mago R, et al. (2013). Antidepressant-induced excessive sweating: Clinical features and treatment with terazosin.https://pubmed.ncbi.nlm.nih.gov/23638448/
Mease PJ, et al. (2010). Long-term safety, tolerability, and efficacy of duloxetine in the treatment of fibromyalgia.https://pubmed.ncbi.nlm.nih.gov/19152958/

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Medically reviewed by Alexandra Perez, PharmD, MBA, BCGP — Written by Patricia Weiser, PharmD — Updated on July 22, 2025

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Key takeaways

More common side effects of Cymbalta

Mild side effects of Cymbalta

Serious side effects of Cymbalta

Side effects in children

Sexual side effects in women and men

Long-term side effects of Cymbalta

FAQ about Cymbalta’s side effects

How long do Cymbalta’s side effects last?

Do older adults have a higher risk for side effects from Cymbalta?

Can Cymbalta cause weight gain?

Will Cymbalta side effects differ depending on the strength I use (20 mg, 30 mg, or 60 mg)?

Boxed warning for Cymbalta

What might help

Help is out there

Tips for managing side effects

Sweating more than usual

What might help

Eye problems

What might help

Liver damage

What might help

Trouble sleeping

What might help

Warnings for Cymbalta

Other warnings

Ask a pharmacist

Q:

A:

How we reviewed this article:

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