Duloxetine: Uses, Side Effects, Dosage, and More

Published March 16th, 2021 by Erik Rivera
Fact Checked by
Camille Freking
Medically Reviewed:
Dr. Gerardo Sison, Pharm.D.
Updated Date: Mar 23rd, 2021

Duloxetine is a generic prescription antidepressant that is approved for the treatment of both physical and mental health conditions. Like other drugs in its class, duloxetine works by acting on the balance of neurotransmitters in the brain which may be linked to mood, communication of pain signals, and more. 

Millions of Americans suffer from common conditions like major depressive disorder, generalized anxiety disorder, fibromyalgia, diabetic neuropathy, nerve pain, and chronic muscle and joint pain, and many of them may find relief from treatment with duloxetine.

What is duloxetine?

Duloxetine is a generic prescription drug that is commonly known by its brand name, Cymbalta. Duloxetine is an antidepressant medication that belongs to a class of drugs called serotonin-norepinephrine reuptake inhibitors (SNRIs). 

SNRIs are one of the newer classes of antidepressants that have been introduced since the 1980s and are generally associated with fewer side effects than older generations of antidepressants, such as tricyclic antidepressants and MAOIs. 

Duloxetine was first approved by the U.S. Food and Drug Administration (FDA) in August 2004 for the treatment of major depressive disorder. Since that time, the drug has been approved for the treatment of a number of other conditions and has become one of the most commonly prescribed antidepressants in the United States. 

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What is duloxetine used to treat?

The first condition approved by the FDA for treatment with duloxetine is a common mental health condition called clinical depression or major depressive disorder. 

Since the initial approval in August 2004, duloxetine has been approved for the treatment of several other mental and physical health conditions, including general anxiety disorder (GAD) in adults and children who are at least seven years old, chronic muscle or joint pain, fibromyalgia, and diabetic neuropathy. 

Clinical Depression/Major Depressive Disorder

Clinical depression, also known as major depressive disorder, is a severe form of depression that is commonly characterized by strong, ongoing feelings of sadness that last for a period of at least two weeks or more. 

Clinical depression is known to cause a wide variety of both physical and mental health-related symptoms, and the intensity of these symptoms can cause a significant decline in a patient’s quality of life. Changes to a patient’s appetite or sleep schedule are common, and many patients find that they lose interest in doing activities or hobbies that they once enjoyed. 

Performing simple daily tasks, such as showering, cooking, or going to work, can become challenging or impossible. Experiencing worsening suicidal thoughts, behaviors, or feelings is also a common symptom of major depressive disorder. 

Other common symptoms of clinical depression include:

  • Feelings of sadness or emptiness

  • Feelings of worthlessness, guilt, hopelessness, or helplessness

  • Sleeping and eating more or less than usual

  • Loss of interest in activities you used to enjoy

  • Mood swings

  • Nervous energy

  • Difficult concentrating and low energy

  • Tiredness or sleepiness

  • Weight loss or weight gain

  • Suicidal thoughts or behaviors

General Anxiety Disorder

Anxiety is a universal human experience that many people experience at various points throughout the course of their lifetimes. Anxiety is the body’s natural response to feelings of fear, stress, or apprehension about the future. 

Occasional feelings of anxiety are perfectly normal, but when they become severe, prolonged, or a regular occurrence that start to interfere with day to day life, a person may be diagnosed with an anxiety disorder. 

While there are many different types of anxiety disorders, one of the most common is a condition called generalized anxiety disorder (GAD). People who suffer from generalized anxiety disorder are plagued by extreme feelings of anxiety that cannot be attributed to any readily identifiable cause. 

Common symptoms of generalized anxiety disorder include an increased heart rate, restlessness, trouble concentrating, rapid breathing, and difficulty falling asleep. 

People with this condition may also occasionally experience an acute form of anxiety known as a panic attack, in which the patient experiences symptoms like dizziness, shortness of breath, dry mouth, sweating, chills, restlessness, distress, fear, hot flashes, worry, numbness, or tingling.

Fibromyalgia

Fibromyalgia causes widespread musculoskeletal pain with no clearly identifiable source. In addition to causing chronic pain, fibromyalgia may cause sleep issues, fatigue, tension headaches, anxiety, mood issues, memory issues, irritable bowel syndrome (IBS), temporomandibular joint (TMJ) disorders, and depression. 

Researchers are still working to understand why fibromyalgia occurs, but current research suggests that the condition may occur as a result of improper processing of pain signals in the brain, which causes amplified feelings of pain throughout the body. 

Fibromyalgia symptoms may first appear after a physical trauma or a period of significant psychological stress, but it may develop gradually over time.

Diabetic Neuropathy

Diabetic neuropathy is a neuropathic pain condition that results from uncontrolled high blood sugar in patients with diabetes. When blood sugar levels are not properly managed, patients may experience a type of nerve damage known as diabetic neuropathy that is particularly common in the legs and feet. Other symptoms associated with diabetic neuropathy can also include digestive issues, urinary tract problems, or blood vessel and heart problems. 

How does duloxetine work?

Medications like duloxetine, which are classified as serotonin and norepinephrine reuptake inhibitors (SNRIs) stabilize the balance of certain chemicals and neurotransmitters in the brain. 

Duloxetine blocks the reuptake, or absorption, of serotonin and norepinephrine by binding to their receptors, thereby increasing the levels of serotonin and norepinephrine. The brain uses serotonin and norepinephrine to communicate with different parts of the body and the central nervous system. 

Having the right levels of these neurotransmitters is essential for a stable mood. Serotonin and norepinephrine may also influence the way that pain signals travel throughout the body and central nervous system. 

The action of duloxetine on serotonin and norepinephrine levels is the reason why the medication has such a wide variety of uses for both mental and physical symptoms. Use of duloxetine helps to improve and stabilize the mood of patients with depression or anxiety and can help relieve pain in certain patients with diabetic neuropathy or fibromyalgia.

How do I know what dose of duloxetine to take?

A patient’s specific dose of duloxetine will be chosen by their healthcare provider based on a number of different factors, including the patient’s age, which form of the drug they take, and the medical condition to be treated with the drug. 

Antidepressants like duloxetine often require several adjustments when a patient first starts treatment before finding the right dose. Most adults suffering from major depressive disorder will take a standard dose of 40 mg of duloxetine per day, taken as one 20 mg release capsule twice per day. Patients with more severe symptoms may have their dose increased to 60 mg per day in the form of a 30 mg capsule taken twice a day or a 60 mg capsule taken once per day. The maximum dose of duloxetine for major depressive disorder is 120 mg per day.

Generalized anxiety disorder in adults is treated with a similar dose to that used for major depressive disorder. The starting dose of duloxetine for generalized anxiety disorder is 60 mg taken once per day, and the maximum dose for this condition is 120 mg per day. 

Older adults, including those over the age of 65, may need to take a lower dose of duloxetine in order to see how their bodies react to the drug before taking a higher dose. When used to treat generalized anxiety disorder in children, duloxetine is prescribed at a starting dose of 30 mg per day before increasing to 60 mg per day, with a maximum of 120 mg per day. 

The standard treatment dose of duloxetine for fibromyalgia or diabetic neuropathy is 60 mg taken once per day. While some patients may believe that taking a higher dose of the drug will lead to increased pain relief, there is no evidence to support that taking a dose higher than 60 mg per day yields any additional benefit in terms of pain management.

Patients who miss a dose of duloxetine should not take extra medication to make up for their missed dose. Take your next dose at your regularly scheduled time.

Does duloxetine cause withdrawal symptoms?

Like many other antidepressants, discontinuing the use of duloxetine can cause withdrawal symptoms in patients who stop or reduce their dose abruptly after taking the drug for at least four to six weeks. Withdrawal symptoms caused by duloxetine are so common that physicians have coined the term “Cymbalta Withdrawal Syndrome,” based on the brand name version of the drug, to refer to the set of symptoms that is commonly caused by the medication. Withdrawal from duloxetine is extremely common, with about 50 percent of patients experience withdrawal symptoms when discontinuing the medication. The best way to minimize symptoms of duloxetine withdrawal is to slowly reduce the dose of the medication over an extended period of time based on a doctor’s guidance. However, even when following this strategy, some patients may still experience withdrawal symptoms. Duloxetine withdrawal symptoms typically dissipate in a few weeks after onset. Symptoms of duloxetine withdrawal include:

  • Nausea

  • Dizziness

  • Electrical shock sensations

  • Depression

  • Drowsiness or fatigue

  • Increased sweating

  • Vomiting

  • Vivid nightmares

  • Muscle spasms or tremors

  • Headache

  • Feelings of anxiety

  • Malaise

  • Irritability

  • Insomnia

  • Seizures

Are there any side effects of duloxetine I should be aware of?

Possible side effects associated with duloxetine are typically characterized as either common or less common. Common side effects associated with duloxetine include:

  • Constipation

  • Diarrhea

  • Insomnia

  • Fatigue

  • Dry mouth

  • Drowsiness

  • Loss of appetite

  • Nausea

  • Headache

  • Dizziness

  • Excessive sweating

  • Sexual dysfunction

  • Abdominal pain or stomach pain

Less common adverse effects that may occur in long-term users of duloxetine include:

  • Suicidal thoughts or behaviors 

  • Liver problems

  • Serotonin syndrome

  • Seizures

  • Increased risk of bleeding

  • Manic episodes

  • Glaucoma

  • Low blood sodium levels

This may not be a complete list of side effects. Consult a healthcare provider for other possible side effects. 

Who should not take duloxetine?

Duloxetine is associated with a number of serious drug interactions that can be potentially dangerous. 

Patients using any of the following medications should not take duloxetine without first receiving approval from their doctor or pharmacist:

  • Monoamine oxidase inhibitors (MAOIs)

  • Mellaril (thioridazine)

The combination of duloxetine and other medications that impact the levels of serotonin in the brain can cause a potentially fatal condition called serotonin syndrome. 

Patients taking any of the following medications should speak to their doctor or pharmacist before using this medication:

  • Selective serotonin reuptake inhibitors (SSRIs)

  • Serotonin and norepinephrine reuptake inhibitors (SNRIs)

  • Lithium

  • Tramadol

  • Linezolid

  • Naproxen

  • Phenelzine

  • Sumatriptan

  • Hydromorphone

  • St. John’s Wort

This may not be a complete list of drug interactions. Consult a healthcare provider for other possible drug interactions associated with duloxetine. 

People who experience an allergic reaction to duloxetine or any of its inactive ingredients should not take the medication.  

Certain medical conditions may put patients at an increased risk of serious side effects or other problems while taking duloxetine. 

People who have a personal or family history of any of the following conditions should provide their doctors with a complete medical history prior to using duloxetine:

  • Bipolar disorder

  • Alcoholism or heavy drinking

  • Kidney or liver problems

  • Use of nonsteroidal anti-inflammatory drugs (NSAIDS)

  • Low or high blood pressure

  • Suicidal thoughts or behaviors

  • Glaucoma (angle-closure type)

Older adults (people over the age of 65) may be more likely to experience certain side effects while taking duloxetine than other people. Among these side effects include an increased risk of gastrointestinal bleeding and a loss of coordination, which increases the patient’s risk of falls. Older adults are also considered to be at increased risk of developing low blood sodium, which can cause confusion, dehydration, and other symptoms.

Summary

Duloxetine is one of the most popular antidepressants on the market and is approved for the treatment of multiple mental and physical health conditions. Duloxetine is commonly associated with side effects like dry mouth, nausea, constipation, and fatigue, and discontinuation of the drug frequently causes withdrawal symptoms. 

Seek medical advice to see if duloxetine is right for you. 

Savings on both the generic and brand name forms of duloxetine can be obtained by purchasing the medication using a pharmacy discount card from USA Rx.

Sources:

https://www.health.harvard.edu/a_to_z/major-depression-a-to-z 

https://www.drugs.com/dosage/cymbalta.html 

https://www.webmd.com/drugs/2/drug-91491/cymbalta-oral/details 

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