Naomi Carr
Author: Naomi Carr Medical Reviewer: Morgan Blair Last updated:

Duloxetine, also known as Cymbalta, is an antidepressant medication, classified as a serotonin-norepinephrine reuptake inhibitor (SNRI), primarily used in the treatment of depression and generalized anxiety disorder. Take this medication exactly as prescribed and consult with your doctor before starting any other medication (prescribed or over the counter) while on duloxetine, as adverse effects can occur.

Duloxetine brand names

  • Cymbalta
  • Drizalma Sprinkle

What is duloxetine prescribed for?

Duloxetine is prescribed for the treatment of major depressive disorder, generalized anxiety disorder, diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain [1].

Duloxetine is not typically prescribed to those under the age of 18, as the safety and effectiveness of the medication in this age group has not been determined. Also, the risk of developing suicidal thoughts while on this medication is higher in younger age groups [2].

How does duloxetine work?

Duloxetine works by affecting serotonin, norepinephrine, and dopamine. It creates an increased concentration of these neurotransmitters in the brain, which helps to improve mood, thereby reducing the symptoms of depression and anxiety [3][4].

Duloxetine also has an effect on noradrenergic and serotonergic neurons and is believed to prevent pain signals from reaching the brain, thus reducing pain and making it an effective treatment for certain physical conditions [3].

How is duloxetine usually taken?

Duloxetine is available as a delayed release capsule in 20mg, 30mg, and 60mg strengths, and as a sprinkle capsule in 20mg, 30mg, 40mg, and 60mg strengths.

The sprinkle capsule can be opened and poured onto a soft food, such as applesauce, which must then be swallowed without chewing. The regular capsule must be swallowed whole, without being broken, crushed, or chewed.

Your treatment may begin with one or two daily doses but will typically be maintained at just one dose per day.

For the treatment of major depressive disorder, you may initially be prescribed two daily doses of 20mg, which can then be increased up to 60mg, to be taken as one dose. The maximum dose that can be prescribed is 120mg per day, although 60mg is generally an effective dose.

For the treatment of generalized anxiety disorder, your dose will likely begin at 60mg, to be taken once per day. Again, the maximum dose is 120mg per day, although 60mg is generally effective [2][4].

For the treatment of diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain, the dose is typically started at 30mg once per day for one week, then increased to 60mg once per day. Higher doses are not advised for these medical conditions, due to increased risk of side effects [2].

This medication should be taken as prescribed, without missing a dose. If a dose is missed, take the medication as soon as possible, or if it is close to the next dosage time, skip the missed dose. Never take duloxetine without proper medical advice, and never double your prescribed dose in one go, as this can have adverse effects and may increase the risk of side effects.

How long does duloxetine stay in your system?

After you begin taking this medication, you may notice some improvements in your symptoms within the first week or two, but it will likely take several weeks, or up to three months of treatment, for duloxetine to take full effect, so it is important to continue taking it as prescribed to ensure it is effective [1].

After you stop taking duloxetine, it may take several days or weeks for the medication to entirely leave your system [2].

Do not suddenly stop taking duloxetine, even if you feel better, as this can have a serious impact on your physical and mental health and can cause an increase in symptoms of depression. If your doctor advises that it is safe to come off this medication, they will likely reduce your prescription slowly, to prevent adverse effects.

Duloxetine side effects

When you begin a new medication, you may experience some common side effects. They will likely reduce within the first week or two, but if they continue or become problematic, consult with your doctor immediately, as you may need a reduced dose or a change of medication.

Common side effects of duloxetine include [1][4]:

  • Abdominal pain, including nausea, vomiting, diarrhea, or constipation
  • Changes in appetite or weight
  • Sweating
  • Restlessness
  • Dry mouth
  • Trouble sleeping
  • Dizziness
  • Headache
  • Shaking
  • Sexual dysfunction

Serious side effects and allergic reactions to duloxetine are less common but may still occur. Contact your doctor immediately if you experience any of the following [2][4]:

  • Yellowing of the skin or eyes
  • Dark urine
  • Pain or swelling in the abdomen
  • Unexplained or unusual bleeding
  • Extreme fatigue
  • Muscle pain, stiffness, or weakness
  • Fever or flu-like symptoms
  • Rapid or irregular heartbeat
  • Difficulty breathing or swallowing
  • Rash, hives, or blisters
  • Swelling on any part of the face or body
  • Changes in vision
  • Seizures
  • Changes in mental state, including hallucinations, delusions, agitation, aggression, mania, or suicidal thoughts

Duloxetine precautions

Duloxetine can cause an increase in suicidal thoughts, particularly at the beginning of your treatment. This risk has been found to be higher in people under the age of 24 years old [2]. If you or your family notice any concerning changes in your mental state, or you experience any thoughts of harming yourself, contact your doctor or mental health professional immediately.

It is important that your doctor is aware of any past or present mental health conditions you have experienced, to enable safe monitoring of your condition while on this medication, or to decide if it is safe for you.

Your doctor may wish to screen you for bipolar disorder prior to starting duloxetine, as there is a risk of antidepressant medication prompting a manic episode in those with bipolar [1].

Discuss with your doctor all your past and present physical health conditions, as they may impact your ability to take this medication safely.

Ensure you tell your doctor if you have experienced any kidney, liver, or heart disease, seizures, serious stomach or blood conditions, glaucoma, or diabetes, as it may not be safe for you to take this medication because of potential side effects [2]. Alternatively, your doctor may wish to prescribe a lower dose and closely monitor your physical health during your treatment.

Discuss with your doctor if you are pregnant or planning to become pregnant, as there is a risk of premature birth if duloxetine is taken in the second and third trimester [1]. It is important that you are aware of the risks to you and your baby that may occur with and without medication, and can make an informed decision about your treatment.

Ensure your doctor is aware if you are breastfeeding, as duloxetine can be excreted in breast milk in small amounts, so there are risks to using this medication while breastfeeding. However, if medication is necessary for your treatment, it is advised to monitor your baby for any concerning changes in their mental or physical state [3].

Depending on your prescription and the length of time you have been on this treatment, you may experience withdrawal symptoms when coming off this medication [5]. Your doctor will likely reduce your prescription slowly to prevent this. Taking duloxetine exactly as prescribed by your doctor can also help to prevent withdrawal symptoms.

This medication can cause drowsiness and sedation, so it is important to avoid driving until you are aware of how duloxetine affects you and it is safe to do so.

Tell your doctor about all medications you are currently taking, or plan to take (including vitamins and dietary supplements), as they may cause adverse reactions.

Duloxetine interactions

Certain antidepressant medications, called monoamine oxide inhibitors (MAOIs), should not be taken with duloxetine, due to the increased risk of serotonin syndrome. There should be a space of at least 14 days between doses of an MAOI and duloxetine [1].

Some medications may interact with duloxetine, impacting the effectiveness of your medication or increasing the risk of side effects. This includes amphetamines, anti-inflammatory medications, blood thinners, diuretics, medications for heart conditions, seizures, migraines, nausea, and chronic pain, sedatives, tranquilizers, and other mental health medications, including antidepressants and anti-anxiety medications [4].

St John’s wort and tryptophan can also interact with duloxetine, potentially causing adverse effects.

Always discuss your medications with your doctor before starting a new treatment.

Duloxetine storage

Always keep all medications out of reach of children.

Store duloxetine in its original packaging, in airtight containers, and at room temperature (never above 86°F).

If you need to dispose of medication that is out of date or no longer needed, contact a medical professional to ensure it is disposed of appropriately. Never flush medications down the toilet or throw them in the trash, as this can create unnecessary risks.

What to do if you overdose on duloxetine

If you overdose on duloxetine, call a medical professional, or Poison Control on 1-800-222-1222, or in case of an emergency, call 911. Symptoms of a duloxetine overdose may include fast or irregular heartbeat, hallucinations, fever, seizure, vomiting, confusion, or coma.

Frequently asked questions about duloxetine

Does duloxetine cause weight gain?

Duloxetine has been found to cause weight loss in short-term use and is not generally considered to cause excessive weight gain [2]. Studies into the long-term use of duloxetine have found that it may cause slight weight gain, particularly in those with a low BMI prior to treatment, but suggests that it may improve low appetite, rather than the medication itself causing an increase in weight [6].

Does duloxetine cause withdrawal symptoms?

Depending on the dosage and length of treatment, duloxetine can cause withdrawal symptoms when discontinuing treatment, which may include dizziness, nausea, nightmares, and irritability [5].

The risk of withdrawal symptoms is higher if you suddenly stop taking duloxetine, so your doctor will gradually reduce your prescription if it is deemed safe to discontinue your treatment, as this can help to prevent withdrawal symptoms. Taking your medication exactly as prescribed by your doctor can also help to prevent unwanted effects [1].

  1. The College of Psychiatric and Neurologic Pharmacists (CPNP) and the National Alliance on Mental Illness (NAMI). (Updated 2016). Duloxetine (Cymbalta). NAMI. Retrieved from https://www.nami.org/About-Mental-Illness/Treatments/Mental-Health-Medications/Types-of-Medication/Duloxetine-(Cymbalta)
  2. Eli Lilly and Company. (Revised 2008). Cymbalta (Duloxetine Hydrochloride) Capsules Medication Guide. Access FDA. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/022516lbl.pdf
  3. Dhaliwal, J.S., Spurling, B.C., & Molla, M. (2022). Duloxetine. In StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK549806/
  4. American Society of Health-System Pharmacists, Inc. (Revised 2022). Duloxetine. MedlinePlus. Retrieved from https://medlineplus.gov/druginfo/meds/a604030.html
  5. Perahia, D.G., Kajdasz, D.K., Desaiah, D., & Haddad, P.M. (2005). Symptoms Following Abrupt Discontinuation of Duloxetine Treatment in Patients with Major Depressive Disorder. Journal of Affective Disorders, 89(1-3), 207–212. Retrieved from https://doi.org/10.1016/j.jad.2005.09.003
  6. Wise, T.N., Perahia, D.G., Pangallo, B.A., Losin, W.G., & Wiltse, C.G. (2006). Effects of the Antidepressant Duloxetine on Body Weight: Analyses of 10 Clinical Studies. Primary Care Companion to the Journal of Clinical Psychiatry, 8(5), 269–278. Retrieved from https://doi.org/10.4088/pcc.v08n0503
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Naomi Carr
Author Naomi Carr Writer

Naomi Carr is a writer with a background in English Literature from Oxford Brookes University.

Published: Feb 20th 2023, Last edited: Sep 22nd 2023

Morgan Blair
Medical Reviewer Morgan Blair MA, LPCC

Morgan Blair is a licensed therapist, writer and medical reviewer, holding a master’s degree in clinical mental health counseling from Northwestern University.

Content reviewed by a medical professional. Last reviewed: Feb 20th 2023