Alternative to Meds Editorial Team
Medically Reviewed by Dr John Motl MD
Don’t stop Cymbalta suddenly. Talk with your prescriber first. If you have thoughts of suicide, call or text 988. For a medical emergency, call 911.
- Medication
- Cymbalta (duloxetine), an SNRI antidepressant also used for nerve pain, fibromyalgia, and chronic muscle and joint pain
- Most common
- Nausea, dry mouth, sleepiness, constipation, lower appetite, and heavy sweating
- How common
- Nausea is the top one: 23% on Cymbalta vs. 8% on placebo in clinical trials
- Serious risks
- Liver injury, serotonin syndrome, bleeding, low sodium, falls from low blood pressure, severe skin reactions, mania, seizures
- Boxed warning
- Higher risk of suicidal thoughts and behaviors in children, teens, and young adults
- Sexual effects
- Low sex drive, erection problems, delayed or absent orgasm
- Stopping
- Dizziness, nausea, headache, “brain zaps,” irritability; the label recommends a gradual reduction
- At ATMC
- Residential, medically supervised tapering in Sedona, Arizona
Table of contents (14)
- What are the side effects of Cymbalta?
- Common Cymbalta side effects
- Serious Cymbalta side effects
- Cymbalta black box warning
- Sexual side effects
- Does Cymbalta cause weight gain?
- Side effects in women, men, and older adults
- Less common side effects by body system
- Side effects reported after approval
- Drug interactions to avoid
- Side effects when stopping Cymbalta
- What is Cymbalta prescribed for?
- Cymbalta side effects FAQs
- Sources
What are the side effects of Cymbalta (duloxetine)?
Short answer: the most common side effects of Cymbalta (duloxetine) are nausea, dry mouth, sleepiness, constipation, decreased appetite, and heavy sweating. Less often, it can cause serious problems such as liver injury, serotonin syndrome, bleeding, low sodium, and falls from a drop in blood pressure.1
Duloxetine is the generic name for Cymbalta, and the side effects are the same for both. Some people have few problems on duloxetine. Others find the side effects hard to live with. Both experiences are real, and both deserve an honest talk with your prescriber.
Side effects are not a reason to stop on your own. Stopping suddenly can cause its own set of symptoms, so any change should be planned with the person who prescribes it.1
Want medical support while you taper? Learn how our residential medication tapering program in Sedona works, or call (888) 907-7075.
Common Cymbalta side effects
Short answer: in clinical trials of adults, nausea affected about 1 in 4 people on Cymbalta. Headache, dry mouth, sleepiness, tiredness, trouble sleeping, constipation, dizziness, and diarrhea each affected about 1 in 10.1
The table below comes from the FDA-approved label. It pools more than 8,000 adults who took Cymbalta in placebo-controlled trials for depression, anxiety, nerve pain, fibromyalgia, and chronic pain. The placebo column shows how often the same complaint happened in people taking a sugar pill.1
| Side effect | Cymbalta | Placebo |
|---|---|---|
| Nausea | 23% | 8% |
| Headache | 14% | 12% |
| Dry mouth | 13% | 5% |
| Sleepiness (somnolence) | 10% | 3% |
| Fatigue or weakness | 9% | 5% |
| Insomnia | 9% | 5% |
| Constipation | 9% | 4% |
| Dizziness | 9% | 5% |
| Diarrhea | 9% | 6% |
| Decreased appetite | 7% | 2% |
| Heavy sweating (hyperhidrosis) | 6% | 1% |
| Abdominal pain | 5% | 4% |
Source: Cymbalta prescribing information, Table 2.1
In the depression and anxiety trials, other side effects that showed up more often than on placebo included vomiting, blurred vision, a pounding heartbeat (palpitations), tremor, agitation or feeling jittery, anxiety, yawning, and sexual side effects.1
Tell your prescriber if these are severe or don’t go away: nausea, vomiting, diarrhea, constipation, appetite or weight changes, dry mouth, sweating or night sweats, tiredness, and sexual problems.2
Serious Cymbalta side effects
Short answer: serious side effects are less common, but you should know the warning signs. Get medical help right away for yellow skin or eyes, signs of serotonin syndrome, unusual bleeding, severe confusion, fainting, a blistering rash, or trouble breathing.1,2
| Serious risk | Warning signs | What the label says |
|---|---|---|
| Liver injury | Upper right belly pain, dark urine, yellow skin or eyes, itching, extreme tiredness | Liver failure, sometimes fatal, has been reported. Avoid with heavy alcohol use or chronic liver disease.1,2 |
| Serotonin syndrome | Agitation, hallucinations, fever, sweating, fast heartbeat, muscle stiffness or twitching, poor coordination, vomiting or diarrhea | Risk rises with other serotonin drugs such as triptans, tramadol, lithium, and St. John’s wort, but it can happen on duloxetine alone.1 |
| Bleeding | Unusual bruising, nosebleeds, black or bloody stools | Risk is higher with aspirin, NSAIDs such as ibuprofen, or warfarin.1 |
| Low blood pressure, fainting, falls | Dizziness when standing, fainting, falls | Most often in the first week or after a dose increase. Older adults are at higher risk of falls.1 |
| Low sodium (hyponatremia) | Headache, confusion, trouble concentrating, weakness, unsteadiness | More likely in older adults and people taking diuretics. Severe cases can cause seizures or coma.1 |
| Severe skin reactions | Blisters, peeling rash, sores in the mouth | Includes Stevens-Johnson syndrome. Stop and get care at the first sign.1 |
| Mania or hypomania | Racing thoughts, little need for sleep, unusual risk-taking | Prescribers should screen for a personal or family history of bipolar disorder.1 |
| Raised blood pressure | Often no symptoms | Blood pressure should be checked before and during treatment.1 |
| Angle-closure glaucoma | Eye pain, vision changes, swelling or redness around the eye | Can occur in people with narrow eye angles that haven’t been treated.1 |
| Seizures | Convulsions | Use with care if you have a seizure disorder.1 |
| Trouble urinating | Weak stream, unable to empty the bladder | Some cases of urinary retention needed hospital care or a catheter.1 |
| Blood sugar changes | Higher fasting glucose and HbA1c | Seen in people with diabetic nerve pain.1 |
Signs that need emergency care now: trouble breathing or swallowing, swelling of the face, lips, or throat, a seizure, fainting, high fever with stiff muscles and confusion, or thoughts of harming yourself. Call 911 or go to the nearest emergency room.2
Cymbalta black box warning
Short answer: yes, Cymbalta has a boxed warning, the FDA’s strongest. It says antidepressants increased the risk of suicidal thoughts and behaviors in children, teens, and young adults in short-term studies.1
The boxed warning on the current label reads, in part:
“Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term studies. These studies did not show an increase in the risk of suicidal thoughts and behavior with antidepressant use in patients over age 24; there was a reduction in risk with antidepressant use in patients aged 65 and older. In patients of all ages who are started on antidepressant therapy, monitor closely for worsening, and for emergence of suicidal thoughts and behaviors.”1
The label asks families and caregivers to watch closely, especially in the first few months and whenever the dose goes up or down.1 Watch for:
- New or worse depression, anxiety, or panic attacks1,2
- Agitation, irritability, hostility, or aggression1
- Severe restlessness (akathisia) or trouble sleeping1
- Acting on impulse, or unusual changes in behavior1,2
- Any talk of suicide or self-harm2
If you notice these signs, call the prescriber right away. If someone is in danger, call or text 988 for the Suicide and Crisis Lifeline, or call 911.18
Sexual side effects of Cymbalta
Short answer: Cymbalta can lower sex drive and cause erection problems, delayed or absent ejaculation, and delayed or absent orgasm. The label asks prescribers to ask about sexual function before and during treatment, because people often don’t bring it up.1
In the depression and anxiety trials, erectile dysfunction was reported by 4% of people on Cymbalta vs. 1% on placebo, and lower sex drive by 3% vs. 1%.1 The label notes that people often don’t report sexual changes on their own, so numbers like these may undercount the problem.1
Some people report sexual symptoms that continue after stopping an antidepressant, known as post-SSRI sexual dysfunction (PSSD). Read more in our article on PSSD and other sexual health risks.
Does Cymbalta cause weight gain?
Short answer: it can go either way. The label lists both weight gain and weight loss as frequent side effects, and decreased appetite affected 7% of adults in trials.1
In children and teens in clinical trials, weight loss was more common: 14% on Cymbalta vs. 6% on placebo. Over the following 4 to 6 months, their weight on average trended back toward expected levels.1 If your weight changes in a way that worries you, tell your prescriber rather than changing your dose.
Side effects in women, men, and older adults
Short answer: most side effects are the same for everyone, but a few are specific to sex or age. The label says no dose change is needed based on sex alone.1
Women:
- Lower sex drive and delayed or absent orgasm1
- Gynecological bleeding and, less often, menstrual changes or menopause-like symptoms1
- Breast milk production when not nursing (galactorrhea), reported after approval1
- During pregnancy: use near delivery may raise the risk of bleeding after birth, and late-pregnancy use may cause breathing, feeding, and temperature problems in the newborn1
If you are pregnant or planning a pregnancy, talk with your prescriber before changing anything. The label notes a risk of relapse when antidepressants are stopped during pregnancy.1
Men: erectile dysfunction, lower sex drive, delayed or failed ejaculation, and, less often, testicular pain.1
Older adults: low sodium and falls are the main concerns. Falls were more common on Cymbalta than placebo in trials, and fall risk rises with age.1 Older adults often take other medicines, such as blood pressure pills or diuretics, that can add to these risks.
Less common Cymbalta side effects by body system
Short answer: the label lists many less common side effects seen in clinical trials. “Frequent” means at least 1 in 100 people, “infrequent” means 1 in 100 to 1 in 1,000, and “rare” means fewer than 1 in 1,000.1
| Body system | Frequent | Infrequent or rare |
|---|---|---|
| Heart | Palpitations | Fast heart rate, heart attack, Takotsubo cardiomyopathy |
| Ears | Vertigo | Ear pain, ringing in the ears (tinnitus) |
| Eyes | Blurred vision | Double vision, dry eye, vision problems |
| Hormones | Underactive thyroid (hypothyroidism) | |
| Digestion | Gas | Trouble swallowing, belching, gastritis, stomach bleeding, bad breath, mouth sores; rare stomach ulcer |
| Whole body | Chills | Falls, feeling abnormal, feeling hot or cold, malaise, thirst; rare unsteady walking |
| Lab results | Weight gain or loss | Higher cholesterol |
| Muscles | Muscle and bone pain | Muscle tightness, muscle twitching |
| Nerves | Altered taste, lethargy, tingling or numbness | Poor attention, involuntary movements, jerks (myoclonus), poor sleep; rare slurred speech |
| Mood and mind | Abnormal dreams, sleep problems | Apathy, teeth grinding, confusion, irritability, mood swings, suicide attempt; rare completed suicide |
| Bladder | Urinating more often | Painful urination, urgency, waking at night to urinate, passing large amounts of urine, unusual urine odor |
| Sexual and reproductive | Orgasm problems | Menopause-like symptoms, sexual dysfunction, testicular pain; rare menstrual problems |
| Skin | Itching | Cold sweats, rash, redness, easy bruising, night sweats, sun sensitivity |
| Blood vessels | Hot flashes | Flushing, low blood pressure on standing, cold hands and feet |
Source: Cymbalta prescribing information, section 6.1.1 Lab tests in trials also showed small average rises in liver enzymes, and high cholesterol was seen more often than on placebo.1
Cymbalta side effects reported after approval
Short answer: since Cymbalta reached the market, people and clinicians have reported more side effects to the FDA. These reports can’t prove the drug caused them or show how often they happen, but they are listed on the label.1
Postmarketing reports listed on the label include:1
- Allergic and skin reactions: anaphylaxis, swelling under the skin of the face or throat (angioedema), hives, rash, and inflamed blood vessels in the skin
- Mood and behavior: aggression and anger, especially early in treatment or after stopping, and hallucinations
- Movement: extrapyramidal disorder, restless legs syndrome, muscle spasm, and jaw muscle spasm (trismus)
- Heart and blood pressure: supraventricular arrhythmia and hypertensive crisis
- Digestion: acute pancreatitis and colitis
- Hormones: high prolactin, breast milk production (galactorrhea), and high blood sugar
- On stopping: seizures and ringing in the ears
You can search or file reports in the FDA Adverse Event Reporting System (FAERS), or report a side effect to FDA MedWatch at 1-800-FDA-1088.1,8 How much weight to give these individual reports, compared with trial data, is an active question in research.17
Struggling with Cymbalta side effects? Talk to our team about medically supervised tapering and what a residential stay looks like.
Call (888) 907-7075Free, confidential consultation
Cymbalta drug interactions to avoid
Short answer: never combine Cymbalta with an MAOI antidepressant, and avoid the antipsychotic thioridazine and strong CYP1A2 blockers such as fluvoxamine and ciprofloxacin. Other serotonin drugs, blood thinners, and heavy drinking raise the risk of serious side effects.1
- MAOIs: don’t take Cymbalta with an MAOI or within 14 days of stopping one. Linezolid and IV methylene blue are also included.1
- Other serotonin drugs: other SSRIs and SNRIs, tricyclics such as amitriptyline, triptans, tramadol, fentanyl, lithium, buspirone, amphetamines, tryptophan, and St. John’s wort raise the risk of serotonin syndrome.1
- Thioridazine: avoid the combination because of the risk of serious heart rhythm problems.1
- CYP1A2 blockers: fluvoxamine raised duloxetine levels about 6-fold in one study. Ciprofloxacin and cimetidine act the same way.1,4
- Blood thinners and pain relievers: aspirin, NSAIDs, and warfarin add to bleeding risk.1
- Alcohol: heavy drinking with duloxetine has been linked to severe liver injury.1
- Smoking: duloxetine levels are about one-third lower in smokers. The label does not recommend a dose change for this.1,4
Bring a full list of your medicines and supplements to every appointment, and ask your pharmacist to check for interactions too.
Side effects when stopping Cymbalta
Short answer: stopping Cymbalta, especially all at once, can cause dizziness, headache, nausea, diarrhea, tingling or “brain zaps,” irritability, vomiting, insomnia, anxiety, sweating, and fatigue. The label recommends a gradual reduction rather than stopping abruptly.1
In a pooled analysis of six short-term trials where duloxetine was stopped abruptly, 44% of people had discontinuation symptoms compared with 23% after stopping placebo. Dizziness was the most common. Most people rated their symptoms mild or moderate. Of the symptoms that cleared during the studies, about two-thirds cleared within a week, but more than half had not cleared by the time the studies ended.3
The label also lists rarer symptoms reported with SSRIs and SNRIs, such as electric shock sensations, confusion, mood swings, ringing in the ears, and seizures. If symptoms become intolerable after a dose cut, the label says your prescriber may go back to the previous dose and then reduce more slowly.1
Why Cymbalta can be hard to taper: it comes as a delayed-release capsule that should be swallowed whole, not crushed, chewed, or opened, so you can’t simply split a dose.1 The available strengths are 20, 30, and 60 mg. Planning the in-between steps is a job for your prescriber and pharmacist, not something to work out on your own.
Long-term side effects of Cymbalta
Most clinical trials of duloxetine lasted weeks to months, so less is known about years of use. In a pooled safety database, about 12% of people took it for at least a year.1 For a closer look at what is known about long-term use, read the long-term side effects of Cymbalta.
What is Cymbalta, generic duloxetine, and what is it prescribed for?
Short answer: Cymbalta is a serotonin and norepinephrine reuptake inhibitor (SNRI). The FDA has approved it for depression, generalized anxiety, diabetic nerve pain, fibromyalgia, and chronic muscle and joint pain.1,10
Cymbalta was first approved in the U.S. in 2004 and in Canada in 2007.1,9,16 It is a delayed-release capsule, coated so it passes the stomach before it dissolves. Its exact mechanism is not fully known. It mainly blocks the reuptake of serotonin and norepinephrine, with a weaker effect on dopamine.1,6 Its half-life is about 12 hours, with a range of 8 to 17 hours.1,5
FDA-approved uses:1
- Major depressive disorder in adults
- Generalized anxiety disorder in adults and children 7 and older
- Diabetic peripheral neuropathic pain (nerve pain) in adults
- Fibromyalgia in adults and teens 13 and older
- Chronic musculoskeletal pain in adults, such as osteoarthritis and chronic low back pain
Off-label uses reported in research include other chronic pain conditions and, in an individual case report, treatment-resistant depression, eating disorders, and OCD.14,15
Duloxetine recalls: since 2024, several makers of generic duloxetine have recalled lots because a nitrosamine impurity, N-nitroso-duloxetine, was found above the FDA’s recommended limit. The FDA classed these as Class II recalls.11,12 Long-term exposure to nitrosamines above safe limits may raise cancer risk, but the FDA advises people not to stop their medicine without talking to a health care provider.13 Your pharmacist can tell you whether your supply was affected.
Watch: what are the negative side effects of Cymbalta?
Get help with Cymbalta side effects
If side effects are hurting your quality of life, start with your prescriber. Options can include changing the dose, the timing, or the medication. If you and your prescriber decide to come off duloxetine, a slow, supervised taper is the safest path.1,3
Alternative to Meds Center is a residential treatment center in Sedona, Arizona, with nearly 20 years of experience helping people taper psychiatric medications. Each resident gets lab testing and a medical assessment on arrival. Our medical team plans each dose step, using half tablets or liquid preparations as needed, and adjusts the pace as you respond. Alongside the taper, the program includes neurotransmitter support, whole-food nutrition, counseling, and dual diagnosis care when depression, anxiety, or chronic pain is part of the picture. These supports work alongside medical care; they don’t replace it.
Our Medical Director describes how the team runs a taper:
“Our medical and nursing teams collaborate closely to monitor each client’s tapering plan, assess progress, and make adjustments as clinically indicated. The team regularly evaluates symptoms, sleep patterns, mood, and overall well-being to support a safe and individualized process.”
Kimberli Galloway, PMHNP-BC, Medical Director
Learn more about Cymbalta withdrawal, Cymbalta tapering, and antidepressant withdrawal help.
Talk to our admissions team. Ask about a supervised Cymbalta taper, what a stay looks like, and insurance. Family members are welcome to call.
Call (888) 907-7075Free, confidential consultation
Cymbalta side effects FAQs
Sources:
1. Eli Lilly and Company. Cymbalta (duloxetine delayed-release capsules) prescribing information. DailyMed, U.S. National Library of Medicine. Revised 8/2023. [cited 2026 Oct 20]
2. MedlinePlus, National Library of Medicine. Duloxetine. [cited 2026 Oct 20]
3. Perahia DG, Kajdasz DK, Desaiah D, Haddad PM. Symptoms following abrupt discontinuation of duloxetine treatment in patients with major depressive disorder. J Affect Disord. 2005;89(1-3):207-212. doi:10.1016/j.jad.2005.09.003. PMID: 16266753. [cited 2026 Oct 20]
4. Knadler MP, Lobo E, Chappell J, Bergstrom R. Duloxetine: clinical pharmacokinetics and drug interactions. Clin Pharmacokinet. 2011;50(5):281-294. doi:10.2165/11539240-000000000-00000. PMID: 21366359. [cited 2026 Aug 13]
5. Carter NJ, McCormack PL. Duloxetine: a review of its use in the treatment of generalized anxiety disorder. CNS Drugs. 2009;23(6):523-541. doi:10.2165/00023210-200923060-00006. PMID: 19480470. [cited 2026 Aug 13]
6. Shelton RC. Serotonin and Norepinephrine Reuptake Inhibitors. Handb Exp Pharmacol. 2019;250:145-180. doi:10.1007/164_2018_164. PMID: 30838456. [cited 2026 Aug 13]
7. Gosmann NP, Costa MA, Jaeger MB, et al. Incidence of adverse events and comparative tolerability of selective serotonin reuptake inhibitors, and serotonin and norepinephrine reuptake inhibitors for the treatment of anxiety, obsessive-compulsive, and stress disorders: a systematic review and network meta-analysis. Psychol Med. 2023;53(9):3783-3792. doi:10.1017/S0033291723001630. PMID: 37278215. [cited 2026 Aug 13]
8. U.S. Food and Drug Administration. FDA Adverse Event Reporting System (FAERS) Database. [cited 2026 Oct 20]
9. Health Canada. Summary Basis of Decision: Cymbalta. Notice of Compliance issued November 1, 2007. [cited 2026 Oct 20]
10. Allgulander C, Hartford J, Russell J, et al. Pharmacotherapy of generalized anxiety disorder: results of duloxetine treatment from a pooled analysis of three clinical trials. Curr Med Res Opin. 2007;23(6):1245-1252. doi:10.1185/030079907X182202. PMID: 17559726. [cited 2026 Aug 13]
11. Gerlach A. FDA Recalls 233,000 Bottles of Duloxetine over Risk of Cancerous Chemical. Pharmacy Times. December 19, 2024. [cited 2026 Oct 20]
12. U.S. Food and Drug Administration. Enforcement Report (search: duloxetine). Class II recalls for N-nitroso-duloxetine, 2024 to 2026. [cited 2026 Oct 20]
13. U.S. Food and Drug Administration. Information about Nitrosamine Impurities in Medications. [cited 2026 Oct 20]
14. Urits I, Peck J, Orhurhu MS, et al. Off-label Antidepressant Use for Treatment and Management of Chronic Pain: Evolving Understanding and Comprehensive Review. Curr Pain Headache Rep. 2019;23:66. doi:10.1007/s11916-019-0803-z. [cited 2026 Aug 13]
15. Safer DL, Arnow KD. Suprathreshold duloxetine for treatment-resistant depression, anorexia nervosa binge-purging type, and obsessive-compulsive disorder: a case report. Innov Clin Neurosci. 2012;9(3):13-16. PMID: 22567604. [cited 2026 Aug 13]
16. U.S. Food and Drug Administration. Cymbalta (duloxetine) label, 2010 revision (initial approval 2004). [cited 2026 Aug 13]
17. Lentacker A. Epistemology of the side effect: anecdote and evidence in the digital age. BioSocieties. 2024;19:84-111. doi:10.1057/s41292-022-00293-5. [cited 2026 Aug 13]
18. 988 Suicide and Crisis Lifeline. 988lifeline.org. [cited 2026 Oct 20]
Originally published August 2026 by Diane Ridaeus. Updated October 2026.
Dr. John Motl, M.D.
Dr. Motl is currently certified by the American Board of Psychiatry and Neurology in Psychiatry, and Board eligible in Neurology and licensed in the state of Arizona. He holds a Bachelor of Science degree with a major in biology and minors in chemistry and philosophy. He graduated from Creighton University School of Medicine with a Doctor of Medicine. Dr. Motl has studied Medical Acupuncture at the Colorado School of Traditional Chinese Medicine and at U.C.L.A.
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Diane is an avid supporter and researcher of natural mental health strategies. Diane received her medical writing and science communication certification through Stanford University and has published over 3 million words on the topics of holistic health, addiction, recovery, and alternative medicine. She has proudly worked with the Alternative to Meds Center since its inception and is grateful for the opportunity to help the founding members develop this world-class center that has helped so many thousands regain natural mental health.