What are the side effects of Duloxetine (Cymbalta)?

From the Guidelines

Cymbalta (duloxetine) can cause several side effects, including nausea, dry mouth, constipation, fatigue, drowsiness, decreased appetite, increased sweating, and dizziness, with the most common adverse effect being nausea, which seems to be reduced by administering 30 mg once daily for 1 week before increasing to 60 mg once daily 1.

Common Side Effects

• Nausea
• Dry mouth
• Constipation
• Fatigue
• Drowsiness
• Decreased appetite
• Increased sweating
• Dizziness These side effects typically appear within the first few weeks of treatment and often improve with time.

Serious Side Effects

More serious side effects that require medical attention include:

• Liver problems (yellowing of skin/eyes, dark urine, abdominal pain)
• Serotonin syndrome (agitation, hallucinations, rapid heartbeat, fever, muscle stiffness)
• Unusual bleeding or bruising
• Eye pain/swelling
• Vision changes
• Severe skin reactions Cymbalta can also cause sexual dysfunction, including decreased libido and difficulty achieving orgasm 1.

Discontinuation and Monitoring

When discontinuing Cymbalta, patients should work with their healthcare provider to taper off gradually rather than stopping abruptly, as withdrawal symptoms like dizziness, nausea, headache, irritability, and "brain zaps" can occur. Blood pressure increases may also occur, so regular monitoring is recommended, especially in patients with hypertension or heart conditions 1. If troublesome side effects persist, patients should consult their healthcare provider about dose adjustments or alternative medications.

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 Cymbalta (duloxetine) include:

• Serious side effects: liver damage, changes in blood pressure, serotonin syndrome, abnormal bleeding, severe skin reactions, discontinuation symptoms, manic episodes, visual problems, seizures, low salt levels, and problems with urination.
• Common side effects: nausea, dry mouth, sleepiness, fatigue, constipation, loss of appetite, increased sweating, and dizziness. 2 2 2

From the Research

Cymbalta Side Effects

• The most common side effects of Cymbalta (duloxetine) include:
  • Nausea 3
  • Headache 3
  • Dry mouth 3
  • Insomnia 3
  • Fatigue 3
  • Constipation 3
  • Diarrhea 3
  • Dizziness 3
• These side effects are usually mild to moderate in severity and tend to emerge early in treatment 3
• The risk of adverse events is higher with Cymbalta than with placebo, with a risk ratio of 1.17 (95% CI 1.12 to 1.23) 4
• The most common reasons for discontinuation due to adverse events were nausea, headache, and dizziness 5

Serious Side Effects

• Serious adverse events (SAEs) are uncommon, and none occurred at a significantly higher frequency for Cymbalta compared with placebo 3
• However, there were reports of suicide-related behavior in 1.1% of patients in a 1-year study 3

Long-term Safety and Tolerability

• Long-term treatment with Cymbalta appears to be safe and well-tolerated, with no new adverse events emerging at a notable rate 6
• The most common treatment-emergent adverse events in long-term studies were nausea and dry mouth 6
• There were no significant within-group changes in blood pressure, but some groups showed small mean increases in pulse 6