What are the side effects of duloxetine (Cymbalta)?

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Last updated: May 7, 2025View editorial policy

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From the Guidelines

Duloxetine can cause several side effects, including common effects like nausea, dry mouth, and dizziness, as well as more serious effects like liver problems, serotonin syndrome, and severe skin reactions, as noted in the 2020 clinical practice guideline for the assessment and treatment of children and adolescents with anxiety disorders 1.

Common Side Effects

  • Nausea
  • Dry mouth
  • Abdominal discomfort
  • Dizziness
  • Headache
  • Tremor
  • Insomnia
  • Somnolence
  • Decreased appetite
  • Weight loss These side effects typically appear within the first few weeks of treatment and often improve with time.

Serious Side Effects

  • Increased blood pressure
  • Liver problems (yellowing of skin/eyes, dark urine, abdominal pain)
  • Serotonin syndrome (agitation, hallucinations, rapid heart rate, fever, muscle stiffness)
  • Unusual bleeding
  • Severe skin reactions
  • Suicidal thoughts These side effects require medical attention and can be life-threatening if not properly managed.

Rare but Serious Side Effects

  • Hepatic failure presenting as abdominal pain, hepatomegaly, and elevation of transaminase levels
  • Cholestatic jaundice
  • Severe skin reactions, including erythema multiforme and Stevens-Johnson syndrome These side effects are rare but can be serious and require immediate medical attention.

Management of Side Effects

Regular follow-up with healthcare providers is essential to monitor and manage these potential effects. Dosage should always be tapered gradually under medical supervision to avoid withdrawal symptoms, as noted in the study on recommendations for the pharmacological management of neuropathic pain 1.

From the FDA Drug Label

Duloxetine delayed-release capsules may cause serious side effects, including:

  1. liver damage. Symptoms may include: itching right upper abdominal pain dark urine yellow skin or eyes enlarged liver increased liver enzymes
  2. changes in blood pressure and falls. 3 Serotonin Syndrome: This condition can be life-threatening and symptoms may include: agitation, hallucinations, coma or other changes in mental status coordination problems or muscle twitching (overactive reflexes) racing heartbeat, high or low blood pressure sweating or fever nausea, vomiting, or diarrhea muscle rigidity dizziness flushing tremor seizures 4 abnormal bleeding: 5 severe skin reactions: 6 discontinuation symptoms: 7 manic episodes:
  3. visual problems:
  4. seizures or convulsions
  5. low salt (sodium) levels in the blood.
  6. problems with urination The most common side effects of duloxetine delayed-release capsules include:
  • nausea
  • dry mouth
  • sleepiness
  • fatigue
  • constipation
  • loss of appetite
  • increased sweating
  • dizziness

The possible side effects of duloxetine delayed-release capsules include:

  • Serious side effects: liver damage, changes in blood pressure and falls, serotonin syndrome, abnormal bleeding, severe skin reactions, discontinuation symptoms, manic episodes, visual problems, seizures or convulsions, low salt levels in the blood, and problems with urination.
  • Common side effects: nausea, dry mouth, sleepiness, fatigue, constipation, loss of appetite, increased sweating, and dizziness. It is essential to monitor patients for these side effects, especially when starting or increasing the dose of duloxetine delayed-release capsules 2, 2, 2.

From the Research

Common Side Effects of Duloxetine

  • Nausea, as reported in studies 3, 4, 5
  • Headache, as reported in studies 3, 6, 5
  • Dry mouth, as reported in studies 3, 6, 4
  • Dizziness, as reported in studies 3, 6, 4
  • Somnolence, as reported in study 6
  • Sexual dysfunction, as reported in study 6

Less Common Side Effects of Duloxetine

  • Dysosmia (distorted sense of smell) and dysgeusia (distorted sense of taste), as reported in study 7
  • Increases in blood pressure, as reported in study 4
  • Discontinuation syndrome, which can be avoided by tapering off the medication over 2 weeks, as reported in study 6

Special Considerations

  • Duloxetine should not be used in combination with CYP 1A2 inhibitors or nonselective, irreversible monoamine oxidase inhibitors, as reported in study 3
  • Patients with a creatinine clearance of <30 mL/min and patients with hepatic impairment should avoid duloxetine, as reported in study 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Safety and adverse event profile of duloxetine.

Expert opinion on drug safety, 2005

Research

Duloxetine: a balanced and selective norepinephrine- and serotonin-reuptake inhibitor.

American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists, 2005

Research

Adverse reactions to duloxetine in depression.

Expert opinion on drug safety, 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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