Cymbalta (duloxetine): uses, side effects, and what to expect

If you or your psychiatrist are considering Cymbalta, you probably have questions about what it does, how it works, and what to expect. Duloxetine is a serotonin-norepinephrine reuptake inhibitor (SNRI) used to treat depression, anxiety, and certain chronic pain conditions. Here is what you should know before starting treatment.

Key takeaways

• Cymbalta (duloxetine) is an SNRI antidepressant approved to treat major depressive disorder, generalized anxiety disorder, fibromyalgia, and chronic musculoskeletal pain.
• It works by increasing levels of serotonin and norepinephrine, two brain chemicals involved in mood, attention, and pain signaling.
• Most people begin to notice improvements within two to six weeks of starting duloxetine.
• Duloxetine should not be stopped suddenly; a gradual taper guided by your psychiatrist helps avoid discontinuation symptoms.

What is Cymbalta?

Cymbalta is the brand name for duloxetine, a medication in the SNRI (serotonin-norepinephrine reuptake inhibitor) class. It is one of the more widely prescribed antidepressants and is used to treat both mood disorders and certain types of chronic pain. Your psychiatrist may refer to it by either its brand name or its generic name, duloxetine.

What does Cymbalta treat?

Duloxetine is FDA-approved for several conditions. Your psychiatrist will determine whether it is a good fit based on your symptoms, medical history, and treatment goals.

On-label uses

• Major depressive disorder (MDD)
• Generalized anxiety disorder (GAD)
• Fibromyalgia
• Chronic musculoskeletal pain (such as low back pain and osteoarthritis)

How does Cymbalta work?

Duloxetine helps restore balance to two chemical messengers in your brain: serotonin and norepinephrine. These chemicals affect your mood, focus, and how your body processes pain signals. By keeping more of them available, duloxetine can ease symptoms of both depression and chronic pain.¹

• Increases serotonin and norepinephrine. Duloxetine slows the reuptake of these brain chemicals, which play key roles in mood, attention, and pain signaling.¹
• Improves mood and emotional balance. By boosting these neurotransmitters, it can reduce symptoms of depression and anxiety.¹
• Reduces pain signaling. Duloxetine can also help manage certain types of chronic pain by affecting how the nervous system processes pain signals.¹

3 things a Talkiatry psychiatrist wants you to know about Cymbalta

• It can help with both mood and pain. Duloxetine is unique among antidepressants for being approved to treat several chronic pain conditions as well. If you struggle with both mood symptoms and physical pain, this may be worth discussing with your psychiatrist.
• It takes time to work. Patients sometimes worry the medication is not doing anything in the first week or two. That is normal. Your psychiatrist will check in with you during this period and can adjust your plan if needed.
• Do not stop suddenly. Your body adjusts to duloxetine over time, so stopping abruptly can trigger what clinicians call discontinuation syndrome: nausea, dizziness, irritability, and other uncomfortable symptoms. If you and your psychiatrist decide to change course, they will create a gradual taper plan so the transition is as smooth as possible.

Common side effects of Cymbalta

Like most medications, duloxetine can cause side effects. Many of these are mild and may improve as your body adjusts to the medication.²

• Nausea, vomiting, diarrhea, or constipation
• Decreased appetite and weight changes
• Dry mouth
• Excessive sweating or night sweats
• Tiredness
• Sexual side effects in males: decreased sex drive, difficulty getting or maintaining an erection, delayed or absent ejaculation
• Sexual side effects in females: decreased sex drive, delayed orgasm or inability to orgasm

Talk to your psychiatrist if any of these feel persistent, severe, or get in the way of your day.

Serious side effects of Cymbalta and when to seek help

Serious side effects are less common but require prompt attention. Contact your psychiatrist or seek emergency care if you notice any of the following.²

• Signs of liver problems: loss of appetite, unusual bruising or bleeding, itching, upper right stomach pain, yellowing of the skin or eyes, dark-colored urine
• Serotonin syndrome symptoms: agitation, hallucinations, fever, sweating, confusion, fast or irregular heartbeat, severe muscle stiffness or twitching, loss of coordination, nausea, vomiting, or diarrhea
• Severe allergic reactions: fever; rash; hives; blistering or peeling skin; difficulty breathing or swallowing; hoarseness; swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
• Seizures
• Extreme tiredness or weakness, confusion, unsteady walking that may lead to falls
• Difficulty urinating
• Increased risk of suicidal thoughts and actions, particularly in children, teenagers, and young adults under 24, especially in the first few months of treatment or when the dose changes

Contact your psychiatrist immediately if you experience new or worsening depression, thoughts of self-harm, panic attacks, severe restlessness, aggressive behavior, or other unusual changes in behavior.²

Call your psychiatrist right away or seek emergency care if you experience any of these symptoms.

What to watch for when starting Cymbalta

Starting a new medication comes with an adjustment period. Here is what to keep in mind during the first few weeks on duloxetine.²

• It may take one to four weeks or longer to feel the full benefit.
• Duloxetine may cause drowsiness or dizziness, or affect judgment, thinking, or coordination. Avoid driving or operating machinery until you know how it affects you.
• Dizziness, lightheadedness, and fainting may occur when getting up too quickly from a lying position, especially when you first start or after a dose increase. Get out of bed slowly.
• Your blood pressure should be checked before starting and regularly during treatment, as duloxetine may raise blood pressure.
• Talk to your psychiatrist about the safe use of alcohol, as it can increase the risk of serious side effects.
• Your psychiatrist may start you on a low dose and increase it after one week.
• Do not stop taking duloxetine suddenly. Stopping the medication too quickly can cause discontinuation symptoms, including nausea, vomiting, diarrhea, anxiety, dizziness, tiredness, headache, tingling in hands or feet, irritability, trouble sleeping, sweating, and nightmares.²

What to do if you miss a dose of Cymbalta

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue your regular schedule. Do not take a double dose to make up for a missed one.²

Who should talk to a psychiatrist before taking Cymbalta

Some health conditions, medications, and life situations change how Cymbalta is prescribed. Tell your psychiatrist if any of the following apply to you.²

• You have a known allergy to duloxetine or any of its ingredients
• You are taking or recently stopped (within two weeks) an MAO inhibitor such as isocarboxazid, linezolid, methylene blue, phenelzine, selegiline, or tranylcypromine
• You are taking thioridazine
• You drink or have drunk large amounts of alcohol, or you have a history of substance misuse
• You have low blood sodium levels
• You have glaucoma or a history of angle-closure glaucoma
• You have recently had a heart attack
• You have high blood pressure, diabetes, seizures, coronary artery disease, bleeding problems, or slow stomach emptying
• You have heart, liver, or kidney disease
• You are pregnant (especially in the last few months), planning to become pregnant, or breastfeeding
• You are an older adult who may be more susceptible to falls from dizziness or unsteady walking