What to Know About Cymbalta (Duloxetine)

An SNRI to Treat Depression and Anxiety

Older man taking pills on bed

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Cymbalta (duloxetine hydrochloride) is an antidepressant in the serotonin-norepinephrine reuptake inhibitor (SNRI) category. It is taken by mouth, as a pill or capsule, and can be prescribed for certain depression and anxiety disorders. 

If you've been given a prescription for Cymbalta or want to learn more about whether it is right for you, it's helpful to understand how this antidepressant works. We also discuss how to take Cymbalta safely, which involves knowing its precautions and contraindications, as well as its potential side effects.

The Most Important Things to Know About Cymbalta (Duloxetine Hydrochloride)

  • Cymbalta should not be taken with a monoamine oxidase inhibitor (MAOI), nor should it be taken by people with uncontrolled narrow-angle glaucoma.
  • Cymbalta has many potential side effects, some of which can be severe, including an elevated risk of suicide and serotonin syndrome.
  • You can develop an addiction or tolerance to this drug.
  • Stopping Cymbalta suddenly can result in withdrawal symptoms.

How Cymbalta Works

As an SNRI, duloxetine inhibits the reuptake of the neurotransmitters serotonin and norepinephrine in the central nervous system. As a result, this increases the amounts available in the brain.

These brain chemicals help regulate mood. So, increasing their levels can relieve symptoms of depression and anxiety. A 2020 review of 85 studies determined that duloxetine is effective for these purposes, both as a short- and long-term treatment.

Improvements in sleep, energy levels, and appetite may be noticed within the first one or two weeks of starting this drug; while other depression and anxiety symptoms may take up to eight weeks to improve.

Uses for Cymbalta

The U.S. Food and Drug Administration has approved Cymbalta for use in the treatment of two mental health conditions: major depressive disorder (MDD) and generalized anxiety disorder (GAD). It is also approved to help treat fibromyalgia, diabetic peripheral neuropathy, and chronic musculoskeletal pain.

Off-Label Cymbalta Uses

Cymbalta is sometimes prescribed off-label in the treatment of stress urinary incontinence. Off-label use means that there is a lack of evidence supporting the safety and/or effectiveness of the drug for that specific condition.

Before Taking Cymbalta

Before prescribing duloxetine, your healthcare provider will evaluate your symptoms and health history. This can help determine if you have any other health conditions that may preclude the use of this medication, or if you are taking any other medications or supplements that may influence the drug's actions.

This is also a good time to become familiar with the warnings, contraindications, and interactions of this drug so you know how to use it safely. Learning its potential side effects is important too, one of which is an increased risk of suicidal thoughts or behaviors in children, teens, and young adults.

Because duloxetine may increase suicide risk in some individuals, talk to your provider about monitoring your symptoms upon beginning this drug.

Warnings and Precautions for Cymbalta

All antidepressants, including Cymbalta, are required to carry a black box warning. This warning states that antidepressants may increase the risk of suicidality in children and young adults under the age of 25.

People taking Cymbalta should be observed closely for worsening depression and suicidality, especially at the beginning of treatment and when changes are made to their prescribed dose. Symptoms to watch for include anxiety, agitation, restlessness, panic attacks, insomnia, irritability, hostility, impulsivity, and hypomania or mania.

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

For more mental health resources, see our National Helpline Database.

Additional warnings for Cymbalta include a potential risk of:

  • Abnormal bleeding
  • Fasting blood sugar increases in people with diabetes
  • Liver failure
  • Low blood sodium levels (hyponatremia)
  • Sudden drops in blood pressure, or blood pressure increases
  • Urinary retention

Serotonin Syndrome

Caution should be used when taking Cymbalta with other medications that increase serotonin, which includes other antidepressants. When taken with drugs that also affect serotonin levels, there is a risk of a serious complication known as serotonin syndrome.

Symptoms of serotonin syndrome can develop in minutes or hours and include increased blood pressure, elevated heart rate, sweating, loss of coordination, agitation, and confusion. You might also experience hallucinations, have overactive reflexes, or have abnormal eye movements.

If you or a loved one develop any of these symptoms, contact your healthcare provider immediately or go to the emergency room as this condition can be life-threatening.

Contraindications for Cymbalta

Cymbalta should not be used by anyone who has shown a sensitivity to duloxetine or any of Cymbalta's inactive ingredients. It should also not be used at the same time as a monoamine oxidase inhibitor (MAOI), or within 14 days of taking this type of drug.

In clinical trials, Cymbalta was associated with increased mydriasis (dilation of the pupil of the eye) in people with uncontrolled narrow-angle glaucoma. So, it should not be used by people with this condition.

Additionally, it is unclear as to whether it is safe to use Cymbalta when pregnant, with some studies finding that duloxetine may be associated with an increased risk of cardiac malformation in the fetus and postpartum hemorrhage. Therefore, it is recommended that the benefits be weighed against the risks before taking Cymbalta during pregnancy.

Drug Interactions for Cymbalta

Duloxetine can interact with a number of other medications and supplements. An interaction can impact the way that this antidepressant works or it may influence the effects of these other substances.

Drugs known to interact with duloxetine include:

  • MAOIs and other antidepressants
  • Warfarin and other blood thinners
  • Migraine medications known as triptans
  • Pain relievers, such as aspirin and ibuprofen
  • Some antibiotics
  • Heartburn medications

To minimize the risk of potentially dangerous interactions, always tell your healthcare provider about any other prescription medications, over-the-counter drugs, vitamins, herbs, or other supplements that you are taking.

Potential Side Effects of Cymbalta

Although duloxetine is considered a safe drug and is generally well-tolerated, side effects can occur.

Common Side Effects

The most common adverse events associated with duloxetine, as reported by greater than 5% of users and appearing twice as often as for individuals taking a placebo or sham medication, include:

  • Nausea
  • Dry mouth
  • Drowsiness
  • Constipation
  • Decreased appetite
  • Excessive sweating

Typically, these side effects go away within the first weeks of treatment, after your body adjusts to the drug. If they don't or if the effects become bothersome, talk with your healthcare provider. They may adjust the dosage or switch you to a new medication.

When first starting duloxetine, you might also feel faint, lightheaded, or dizzy when moving too quickly from a lying to a standing position. This is due to blood pressure changes. Getting up slowly can help ease this effect.

Severe Side Effects

More serious side effects of duloxetine can include:

  • Abnormal bruising or bleeding
  • Abdominal pain or swelling
  • Yellowing of the eyes or skin
  • Extreme fatigue or weakness
  • Confusion or agitation
  • Trouble walking or urinating
  • Severe muscle twitching or stiffness
  • Hallucinations
  • Difficulty breathing or swallowing
  • Fast or irregular heartbeat

If serious side effects occur after taking Cymbalta, contact your healthcare provider or go to the nearest emergency room for immediate treatment.

Dosage of Cymbalta

When prescribed for depression or anxiety, Cymbalta is often administered to a target dose of 60 milligrams (mg) per day. The maximum dosage for this drug is 120 mg daily. However, higher doses of duloxetine are associated with more adverse effects without more positively impacting symptom reduction.

These dosages are according to the drug manufacturer. Check your prescription and talk to your healthcare provider to ensure that you are taking the right dose for you.

How to Take

The delayed-release capsules should be swallowed whole and never crushed or chewed. It is not necessary to take this medication with food.

If you miss a dose of duloxetine, you should take it as soon as you remember, unless it is close to the time for your next dose. In this case, simply skip the missed dose and take your regular dose on schedule. 

Never take two doses at once to make up for a missed dose as it is possible to overdose on this drug. Symptoms of a Cymbalta overdose can include rapid heart rate, seizures, and high blood pressure; when taken in high doses with other drugs, it can lead to low blood pressure and coma.

Contact emergency services immediately if you believe that you or someone else has overdosed on Cymbalta.

Cymbalta Misuse

There is a risk of becoming addicted to duloxetine or developing a tolerance to this drug. Both instances can lead to its misuse by causing a person to take more than is prescribed.

Misusing drugs can lead to greater side effects and the potential for overdose. That's why it's important to use Cymbalta as directed. Speak with your healthcare provider if you are concerned that you may be developing an addiction or tolerance to this drug.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

Discontinuing Cymbalta

It is common to experience withdrawal symptoms after reducing the dosage of or completely stopping antidepressant drugs such as duloxetine. Some of the most reported Cymbalta withdrawal symptoms include:

  • Dizziness
  • Anxiety
  • Nausea
  • Trouble sleeping
  • Irritability

Your physician can advise you about how to reduce or stop your medication, which may involve gradually reducing your dosage. The latter gives your body time to adjust to lower amounts of the drug before eliminating it altogether.

Never stop taking Cymbalta, or any other antidepressant, without first discussing this with your healthcare provider.

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Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Nancy Schimelpfening
Nancy Schimelpfening, MS is the administrator for the non-profit depression support group Depression Sanctuary. Nancy has a lifetime of experience with depression, experiencing firsthand how devastating this illness can be.