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Cymbalta (duloxetine) Side Effects: Critical Safety Info

Last Updated on August 17, 2026 by Diane Ridaeus

Alternative to Meds Editorial Team

Here, one can explore what has been reported in-depth about Cymbalta side effects, and its generic equivalent duloxetine — not to frighten — but to inform the important decisions about personal health.

We cannot dismiss drug “side” effects as unimportant. A drug such as Cymbalta/duloxetine may be prescribed correctly, at the right dosage, for the approved condition — and yet may result in unwanted outcomes. Be safe. Learn more.


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What is Cymbalta, generic duloxetine, and what is it prescribed for?

SNRI antidepressantCymbalta is an SNRI antidepressant, the patents of which expired back in 2013. Its generic equivalent, duloxetine hydrochloride has been widely available for more than a decade.  However, in 2024, and again in 2025 the FDA issued safety recalls due to a cancer-causing element found in the duloxetine formulation. Duloxetine has become hard to find in some areas, as a quarter of a million bottles have been recalled so far, according to industry reports.

Seek medical assistance if this has become a problem for you or a loved one, as abrupt cessation of any antidepressant is not recommended. Alternatives may be available that could help avoid this potential problem.

Sometimes duloxetine is called an SSNRI, meaning Selective Serotonin Norepinephrine Reuptake Inhibitor. It is a time-released drug. It’s mechanism of action is unknown, but regulators believe it selectively targets certain neurotransmitters such as serotonin, norepinephrine (adrenaline), dopamine to a lesser degree, and possibly others.

Cymbalta was FDA-approved to treat the following:
  • MDD (major depressive disorder)
  • GAD (generalized anxiety disorder) in adult patients
  • Neuropathy (nerve pain) in diabetic patients
  • Pain of Fibromyalgia
  • Chronic muscular/skeletal pain
Off-label uses for Cymbalta/duloxetine 12,14 reportedly include:
  • Chemotherapy associated pain
  • Post-operative pain
  • Treatment-resistive depression
  • Eating disorders
  • OCD (obsessive compulsive disorder)

What are the reported side effects of Cymbalta and duloxetine?

Side effects for Cymbalta/duloxetine make a very long list. Some are severe enough to warrant the highest level warnings issued by the FDA, including a black box warning.

Black box statements for Cymbalta/duloxetine include:
  • Suicidality in children, and young adults.
  • Not approved for use in pediatric patients
Warnings and Precautions prominently listed on the drug label include:
  • Cymbalta use has risk of suicidality in children & young adultsToxic to liver, can cause liver failure and fatality
  • Orthostatic hypotension (low blood pressure) and syncope (fainting, falls from sudden drop in blood pressure)
  • Increases in high blood pressure compared to placebo
  • Serotonin syndrome (can be fatal)
  • NMS (neuroleptic malignant syndrome) life-threatening drug reaction: very high fever, rigidity, altered mental state, suddenly can’t speak or swallow, rapid breathing, loss of bladder/bowel control, excessive sweating, fluctuations in blood pressure and heart rate, renal failure, sepsis, cardiac arrest.
  • Abnormal bleeding, may be worsened by aspirin, NSAIDS, other drugs affecting coagulation of blood
  • Mania, or hypomania (mania of shorter duration or intensity)
  • Seizures
  • Duloxetine causes dilated pupils, which is a risk for narrow angle glaucoma
  • Glycemic dysregulation found in a study on diabetic patients (fluctuating blood sugar levels)
  • Urinary retention, may require use of a catheter
  • Slowed gastric emptying
  • Hyponatremia (low sodium levels) leads to headache, nausea, confusion, loss of energy, restlessness, irritability, muscle spasms, cramps, seizures, swelling in the brain, coma, hallucination, respiratory arrest, can be fatal if not treated promptly
  • Withdrawals when Cymbalta or duloxetine is stopped, include seizures and other reactions.

For more information on Cymbalta/duloxetine withdrawal symptoms and treatment please see:

Cymbalta Withdrawal, Tapering & Alternatives (Safe Duloxetine Guide)
Antidepressant Withdrawal Help | Professional Effective Support

Adverse reactions observed in clinical trials according to the drug’s label include:
  • Nausea/vomiting
  • Dizziness
  • Headache
  • Physical weakness (asthenia)
  • Dry mouth
  • Mood swings
  • Irritability
  • Apathy
  • Disorientation
  • Daytime sleepiness
  • Constipation
  • Excessive sweating
  • Cold sweats, chills
  • Hot flushes, reddening of the skin (erythema)
  • Decreased appetite
  • Stomach ulcers
  • Dysregulated or elevated fats in the blood, high cholesterol (hyperlipidemia, dyslipidemia))
  • Halitosis (bad breath)
  • Bruxism (grinding, clenching of teeth)
  • Sensitivity to light
  • Anorexia
  • Indigestion
  • Flatulence
  • Passage of bright red blood from rectum (hematochezia)
  • Pain when urinating (dysuria)
  • Abnormal smell of urine
  • Frequent nighttime urination (nocturia)
  • Polyuria (urinating more than 3 L per 24 hr)
  • Black tarry stools (melena)
  • Thirst, dehydration
  • Abdominal pain
  • Weight loss
  • Insomnia
  • Abnormal dreams
  • Jittery, tension, nervousness, restlessness, malaise
  • Agitation, psycho-motor agitation
  • Anxiety
  • Erectile dysfunction in males
  • Anorgasmia (inability to orgasm in females)
  • Influenza, laryngitis
  • Viral or bacterial infection of the stomach/intestines
  • Cough
  • Muscle spasms
  • Gait disturbance
  • Tremor, muscle twitching, muscle tightness
  • Bruises easily (ecchymosis)
  • In animal studies duloxetine caused reactions in the newborns similar to serotonin syndrome and possibly related to withdrawal syndrome.

Additional Cymbalta Side Effects Categorized and Clearly Defined

In addition to the above list, other adverse effects of Cymbalta/duloxetine are categorized by disorder type, and are listed as frequent, or infrequent.

Cardiac Disorders associated with Cymbalta include:
  • Frequent heart palpitations
  • Infrequent heart attack, tachycardia (elevated heart rate when body is at rest)
Ear and inner ear disorders associated with Cymbalta include:
  • Frequent vertigo
  • Infrequent ear pain, tinnitus
Endocrine disorders associated with Cymbalta include:
  • Infrequent hypothyroidism (insufficient thyroid hormones) can lead to depression, fatigue, weight gain, intolerance to cold, inability to sweat, brittle fingernails and toenails, hair loss or thinning, puffy face, irregular menses in women, infertility, enlarged thyroid or goiter, joint or muscle pain)
Eye disorders associated with Cymbalta include:
  • Frequent blurred vision
  • Infrequent diplopia (double vision) and visual disturbance
Nervous system disorders associated with Cymbalta include:
  • Frequent distorted sense of taste, parasthesia (pins and needles), numbness
  • Infrequent nerve damage causing speech impairment, involuntary movement, disturbed attention

Some Post-Marketing Adverse Side Effects of Cymbalta/duloxetine Listed on the Drug Label

  • seizures are known side effect of Cymbalta/duloxetine useStevens Johnson Syndrome, or other severe rashes and anaphylactic reactions, which can be life-threatening and need immediate medical intervention
  • Aggression, anger, particularly early in treatment or when Cymbalta is discontinued
  • Sudden or rapid swelling under the skin of the face, neck, or other areas, can block the airway, impair quality of life due to unpredictable onset (angioneurotic edema)  
  • Hives, itchy red welts that are raised on the skin, swelling (urticaria)
  • Appearance of target-like lesions with red rings around a pale center, can be fatal (multiforme)
  • Extrapyramidal disorders, not specified on the label, can be immediate as in restless legs, and seizures, especially on discontinuation of the drug, or tardive as in tardive dyskinesia
  • Hallucinations
  • Painful spasms in the jaw muscles (trismus)
  • Supraventricular tachycardia — an elevated heart rate which can cause cardiac arrest, stroke, unconsciousness, decrease the pumping action of the heart muscle, or increase risk of blood clots.

Cymbalta/duloxetine Drug-Drug Interactions to Avoid

Certain drugs should be avoided while taking Cymbalta/duloxetine because of the way they interact. Some, but not all of the drugs to avoid, are listed on the drug’s label.  

Examples of drugs to avoid while taking Cymbalta/duloxetine include:
  • Other drugs or substances that elevate serotonin levels, such as St. John’s Wort, tryptophan, Prozac, other SSRIs, other SNRIs, lithium, and tricyclic antidepressants such as amitriptyline
  • The antipsychotic thioridazine, when combined with duloxetine can result in sudden death.
  • Combining duloxetine with heavy alcohol use can lead to severe liver injury
  • Combining duloxetine with aspirin, NSAIDs, warfarin, or other drugs that affect blood coagulation should be avoided
  • Smoking cigarettes while taking Cymbalta/duloxetine can decrease the concentration of duloxetine by 30%.

Please ensure your doctor and you are on the same page before combining duloxetine with any other substances to avoid these and other dangerous side effects. You may have to do the research yourself, as doctors are rushed and time-constraints can lead to unintended errors in judgement.

1 (800) 301-3753 for Help with Cymbalta/duloxetine Side Effects

Cymbalta Side Effects FAQs

Although the patents have expired on the brand name drug Cymbalta, duloxetine hydrochloride remains on the market, Cymbalta’s generic equivalent. The side effect profile is reportedly similar, if not identical, between brand name and generic drugs.

Why was duloxetine recalled?

A cancer risk was found in duloxetine formulations in 2024 and again in 2025, when approximately a quarter million bottles were taken off the market. While new batches of duloxetine are being produced to fill the supply gap, the drug may be hard to find for some time yet.11

What are the neurotransmitters believed to be affected by Cymbalta/duloxetine?

The drug label states that it is believed that Cymbalta most strongly affects serotonin and norepinephrine (adrenaline). Dopamine is believed to be affected less so, and other neurotransmitters like choline, histamine, etc. are likely not affected at all.1,4,13

Are all SNRI drugs associated with similar side effects?

In general, yes SNRI drugs have similar side effect profiles, but comparative studies indicate certain SNRIs have differences in how common, intense, or rare a particular side effect may be.4,5,12

Where can I find out more about Cymbalta side effects and duloxetine?

The FAERS portal can be checked for more information on Cymbalta side effects. FAERS stands for FDA adverse event reporting system, which anyone can access for information, and to which reports can be submitted.7

When was the immediate-release version of Cymbalta discontinued in the US and other countries?

Cymbalta was first approved in 2004.1,13 During the period of 2004 – 2007 the immediate-release versions of Cymbalta (duloxetine) were either not approved, or were discontinued in the US and by regulators in other countries.8

What is the half-life of duloxetine?

Researchers say the half-life of duloxetine is approximately 12 hours. This means that half the active drug will have been eliminated from the body by 12 hours after taking it.6

Does smoking cigarettes interfere with Cymbalta/duloxetine?

Yes. Smoking cigarettes while taking Cymbalta is associated with a 30% decrease in concentration of the drug, but increasing the dose to compensate is not recommended.1,13

Sources:

1. FDA label and prescribing information Cymbalta (duloxetine hydrochloride) Delayed Release Capsules for Oral Use last reviewed 2026, first approval 2004 [cited 2026 Aug 13]

2. Knadler MP, Lobo E, Chappell J, Bergstrom R. Duloxetine: clinical pharmacokinetics and drug interactions. Clin Pharmacokinet. 2011 May;50(5):281-94. doi: 10.2165/11539240-000000000-00000. PMID: 21366359. [cited 2026 Aug 13]

3. Carter NJ, McCormack PL. Duloxetine: a review of its use in the treatment of generalized anxiety disorder. CNS Drugs. 2009;23(6):523-41. doi: 10.2165/00023210-200923060-00006. PMID: 19480470. [cited 2026 Aug 13]

4. 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]

5. Gosmann NP, Costa MA, Jaeger MB, Frozi J, Spanemberg L, Manfro GG, Cortese S, Cuijpers P, Pine DS, Salum GA. 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 Jul;53(9):3783-3792. doi: 10.1017/S0033291723001630. Epub 2023 Jun 6. PMID: 37278215. [cited 2026 Aug 13]

6. Carter NJ, McCormack PL. Duloxetine: a review of its use in the treatment of generalized anxiety disorder. CNS Drugs. 2009;23(6):523-41. doi: 10.2165/00023210-200923060-00006. PMID: 19480470. [cited 2026 Aug 13]

7. FDA Adverse Event Reporting System [cited 2026 Aug 13]

8. Health Canada Summary Basis of Decision for Cymbalta updated 2026 [cited 2026 Aug 13]

9. Allgulander C, Hartford J, Russell J, Ball S, Erickson J, Raskin J, Rynn M. Pharmacotherapy of generalized anxiety disorder: results of duloxetine treatment from a pooled analysis of three clinical trials. Curr Med Res Opin. 2007 Jun;23(6):1245-52. doi: 10.1185/030079907X182202. Epub 2007 Apr 25. PMID: 17559726. [cited 2026 Aug 13]

10. Lentacker, A. Epistemology of the side effect: anecdote and evidence in the digital age. BioSocieties 19, 84–111 (2024). https://doi.org/10.1057/s41292-022-00293-5 published Dec 22, 2022 [cited 2026 Aug 13]

11. Gerlach, A FDA Recalls 233,000 Bottles of Duloxetine over Risk of Cancerous Chemical, published December 19, 2024, Pharmacy Times [cited 2026 Aug 13]

12. Urits, I., Peck, J., Orhurhu, M.S. et al. Off-label Antidepressant Use for Treatment and Management of Chronic Pain: Evolving Understanding and Comprehensive Review. Curr Pain Headache Rep 23, 66 (2019). https://doi.org/10.1007/s11916-019-0803-z [cited 2026 Aug 13]

13. FDA label Cymbalta/duloxetine approval 2004, revised 2008, 2009 & 2010 [cited 2026 Aug 13]

14. 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 Mar;9(3):13-6. PMID: 22567604; PMCID: PMC3342990. [cited 2026 Aug 13]

Originally Published August __, 2026 by Diane Ridaeus

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ATMC Clinical Review Team

The ATMC Clinical Review Team includes licensed physicians and experienced healthcare professionals dedicated to ensuring the accuracy, quality, and integrity of our medical content. The team reviews articles for clinical accuracy, evidence-based guidance, and relevance while supporting Alternative to Meds Center’s whole-person approach to mental health, recovery, and long-term wellness.

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