Duloxetine Side Effects: A Complete Guide

Prescription medications often come with side effects — you hear them rattled off at the end of a commercial and roll your eyes, wondering: “Are the benefits really worth the risks?” 

Just because side effects are possible doesn’t make them likely. And even in cases where you experience side effects, they’re often preferable to the symptoms you’re trying to treat. 

Living with depression or chronic pain can be miserable. Duloxetine, along with many other prescription medications, may be able to help. 

Your healthcare provider can help you determine if the potential risks are worth the proven benefits, and help get you on the road to brighter days.

What is Duloxetine? 

Duloxetine is an antidepressant drug often sold under the brand name Cymbalta®. Cymbalta was approved for use by the FDA in 2004, and it and its generic equivalent duloxetine are prescribed for several different mental health conditions, including: major depressive disorder, generalized anxiety disorder, diabetic nerve pain, fibromyalgia and chronic musculoskeletal pain. 

Its use in the treatment of pain disorders make it unique from many other antidepressant medications.

Duloxetine is what’s known as a serotonin-norepinephrine reuptake inhibitor, or SNRI. These drugs work primarily on two chemicals in the brain: serotonin and norepinephrine. 

By increasing the amount of these two neurotransmitters in the brain, the drug is able to have positive effects on mood and improve pain conditions. 

These potent effects are responsible for getting duloxetine FDA approval for treatment of more conditions than any other SNRIs. 

It’s not unusual for chronic pain (part of somatic symptom disorder), like that experienced with diabetic neuropathy or fibromyalgia, to go hand-in-hand with depression. 

And healthcare professionals once thought the reasons were psychological — pain feels bad and can change your lifestyle, and that can be depressing. But now, evidence suggests there are also biological factors.

Major depression is quite common, affecting 17.3 million U.S. adults, according to the National Institute of Mental Health. 

So, whether you suffer from a pain condition too, or you’re just depressed, you’re not alone. And drugs like duloxetine may be able to provide some relief.

Common Duloxetine Side Effects 

There are risks of side effects with duloxetine, as with many prescription drugs. 

The most common side effects, occurring in at least five percent of cases, include: nausea, sleepiness or tiredness, dry mouth, fatigue, constipation, decreased appetite and excessive sweating. 

To learn about other potential side effects, we have articles on Cymbalta and weight gain and how to sleep while taking Cymbalta.

Other Duloxetine Risks, Drug Interactions 

Duloxetine may also negatively interact with other drugs, so make sure to tell your healthcare provider about all of the medications you currently take — prescription, over-the-counter, and even nutritional supplements before you get a prescription for duloxetine online.

Some drugs that don’t “play well” with duloxetine include: blood thinners, other antidepressants, non-steroidal anti-inflammatory drugs (NSAIDs) such as naproxen and ibuprofen, diuretics, fentanyl, St. John’s wort, some medications for migraines, anxiety, high blood pressure and more. There are also certain foods to avoid when taking Cymbalta.

Duloxetine can increase your chances of suffering from serious adverse effects including abnormal bleeding, liver failure, seizures, mania and a potential lethal condition called serotonin syndrome. 

If you experience abnormal or serious side effects when switching your medication to duloxetine or while taking it, it’s important you contact your healthcare provider for proper medical advice right away. 

If you decide to go off of duloxetine, talk with your healthcare provider about how best to do this. The medication can cause withdrawal symptoms if you stop suddenly, so they may opt to slowly wean you off your dosage to minimize these effects.

In the early phases of treatment, you may experience worsening depression including suicidal thoughts or tendencies. Do not ignore these feelings. Contact your healthcare provider immediately if your depression symptoms seem to be getting worse.