Duloxetine (Cymbalta, Drizalma Sprinkle) - Uses, Side Effects, and More

What are the most common side effects of duloxetine?

The most common side effects of duloxetine are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

• Nausea
• Dry mouth
• Dizziness
• Drowsiness or tiredness
• Constipation
• Feeling less hungry 
• Sweating
• Slowed growth (see below)
• Diarrhea (in children)

There may be other side effects of duloxetine that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of duloxetine?

While less common, the most serious side effects of duloxetine are described below, along with what to do if they happen.

Severe Allergic Reactions. Duloxetine may cause allergic reactions, which can be serious. Stop taking duloxetine and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching, skin rash, or pale red bumps on the skin called hives
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Suicidal Thoughts or Actions. Duloxetine or other antidepressants may increase the risk of suicidal thoughts or actions in a small number of children, teenagers, or young adults in the first few months of taking the medicine or when the dose is changed. Depression or other serious mental health conditions are the most important causes of suicidal thoughts or actions. If you or your child is about to harm themselves, call 911 or call or text 988, the Suicide & Crisis Lifeline. Call your healthcare provider right away if you have any of the following symptoms.

• New or increased thoughts of suicide or death
• Suicide attempt
• New or increased feelings of anxiety, depression, or other unusual changes in your mood or behavior

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking duloxetine. Stop taking duloxetine and call your healthcare provider right away if you have any of the following symptoms of liver damage.

• Nausea or vomiting
• Stomach or belly pain
• Fever
• Weakness or unusual tiredness
• Itching
• Loss of appetite
• Light-colored poop
• Dark-colored urine (pee)
• Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Low Blood Pressure Upon Standing (Orthostatic Hypotension) and Falls. Duloxetine may cause a sudden drop in blood pressure when standing up from a seated or lying position. This can sometimes lead to fainting or falls. Falls can lead to serious problems including fractures. To help prevent this, be careful not to get up too quickly. If you feel dizzy, sit or lie down right away until the dizziness stops, then take your time getting up again. Tell your healthcare provider right away if you have any of the following symptoms of orthostatic hypotension.

• Dizziness, feeling lightheaded, or fainting upon standing
• Blurred vision
• Confusion
• Feeling weak

Serotonin Syndrome. Serotonin syndrome is when there is too much of a substance called serotonin in your body. Duloxetine can cause serotonin syndrome when it is taken alone or with other medicines that affect serotonin. This condition can be life-threatening. Get emergency help if you have any of the following symptoms of serotonin syndrome.

• Sweating, fever, or flushing
• Confusion
• Feeling agitated or restless
• Seeing or hearing unusual things
• Dizziness
• Fast or racing heartbeat
• Nausea, vomiting, or diarrhea
• Muscle twitching, stiffness, or tremor
• Seizures

Increased Blood Pressure (Hypertension). Duloxetine may increase your blood pressure or make it worse if you have a history of high blood pressure. Call your healthcare provider if your blood pressure increases while taking this medicine.

If you measure your blood pressure and the top number (systolic) is 180 mm Hg or higher or the bottom number (diastolic) is 120 mm Hg or higher, get medical attention right away. Increases in blood pressure may not be noticeable but look out for any of the following symptoms of severely high blood pressure.

• Sudden severe headache
• Chest pain
• Dizziness or confusion
• Trouble breathing
• Nausea/vomiting
• Blurry or other changes to vision
• Anxiety
• Buzzing in the ears
• Nosebleed
• Feeling of skipped heartbeats

Abnormal Bleeding. People taking duloxetine or other antidepressants may have an increased risk of bleeding or bruising. You may be at higher risk if you are also taking aspirin, a nonsteroidal anti-inflammatory drug (NSAID), like ibuprofen or naproxen, or a blood thinner such as warfarin, apixaban (Eliquis), or rivaroxaban (Xarelto). Tell your healthcare provider if you notice any changes in how easily you bruise or bleed.

Extremely Elevated Mood (Mania). People with bipolar disorder can have severe high and low moods. The first symptom of bipolar disorder may be depression. People with bipolar disorder who take an antidepressant, such as duloxetine, may have a higher risk of having mania or a manic episode. Call your healthcare provider right away if you have any of the following symptoms of a manic episode.

• Very increased energy
• Significant trouble sleeping
• Racing, fast-paced thoughts
• Reckless behavior
• Unusually grand ideas
• Excessive happiness or irritability
• Talking more or faster than usual

Severe Skin Reactions. duloxetine can cause severe skin reactions called Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) that can lead to death if not treated. If you develop a rash, stop duloxetine and call your healthcare provider right away. Get emergency help right away if you have any of the following symptoms of SJS or TEN.

• Painful red or purple skin that looks burned and peels off
• Flat red rash or blisters on your skin, mouth, nose, and genitals
• Red, painful, watery eyes

Glaucoma. Duloxetine may increase pressure inside the eye and cause or worsen narrow-angle glaucoma, which can lead to blindness. Tell your healthcare provider right away if you have any of the following symptoms of glaucoma.

• Loss of vision
• Eye pain or redness
• Severe headache or vomiting
• Seeing bright, colorful circles around lights (vision halos)

Seizures. Some people who have taken duloxetine have reported having seizures. There are many different types of seizures and some of them are not easy to recognize. Stop taking duloxetine and call your healthcare provider if you have any of the following signs that a seizure is happening or could happen.

• Muscle twitching, jerking, spasms, tremors, or other uncontrolled movements
• Stiffening of your arms and legs
• Feeling anxious, nervous, confused, or a sense of dread
• Feeling dizzy or lightheaded
• Falling or losing consciousness

Low Sodium Level (Hyponatremia). Duloxetine may cause low sodium levels. Stop taking duloxetine and call your healthcare provider if you have any of the following symptoms of a low sodium level.

• Headache
• Drowsiness
• Muscle weakness or cramps
• Nausea, vomiting, or loss of appetite
• Tiredness or sleepiness
• Dizziness
• Weight gain
• Restlessness or irritability
• Change in your mental condition such as hallucinations, confusion, decreased awareness, or alertness
• Seizures

Inability to Empty Bladder (Urinary Retention). Duloxetine might make it harder to empty your bladder, especially if you already have a blockage. Call your healthcare provider right away if you are having trouble peeing or cannot empty your bladder.

Sexual Problems. Taking duloxetine or another selective serotonin reuptake inhibitor (SSRI) may cause sexual problems. Tell your healthcare provider if you have any of the following sexual problems. 

• Decreased sex drive
• Delayed ejaculation or unable to have an ejaculation
• Problems getting or keeping an erection
• Delayed orgasm or unable to have an orgasm