Does duloxetine cause somnolence?

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From the Guidelines

Duloxetine can cause drowsiness as a side effect in some people who take it, with the most frequent adverse effects including nausea, somnolence, dizziness, constipation, dry mouth, and reduced appetite, although these tend to be mild to moderate and are transient 1.

Causes of Drowsiness

The drowsiness occurs because duloxetine affects neurotransmitters in the brain, particularly serotonin and norepinephrine, which can influence sleep-wake cycles.

  • Duloxetine has been shown to be effective in relieving painful symptomatology, with approximately 50% of patients achieving at least 50% pain reduction 1.
  • The most common adverse effects of duloxetine include nausea, somnolence, dizziness, constipation, dry mouth, and reduced appetite 1.

Management of Drowsiness

If you're experiencing significant drowsiness while taking duloxetine, consider taking it at bedtime rather than in the morning to minimize daytime sleepiness.

  • Don't abruptly stop taking duloxetine as this can cause withdrawal symptoms; instead, consult your healthcare provider if drowsiness is problematic 1.
  • Other strategies to manage drowsiness include avoiding alcohol, maintaining a regular sleep schedule, and avoiding driving or operating machinery until you know how duloxetine affects you.
  • If drowsiness persists beyond a few weeks or is severe, contact your healthcare provider promptly, as they might adjust your dosage, change the timing of your dose, or recommend a different medication 1.

From the FDA Drug Label

The most commonly observed adverse reactions in duloxetine delayed-release capsules-treated patients (as defined above) were: ... somnolence Adverse reactions reported as a reason for discontinuation and considered to be drug-related (as defined above) included ... somnolence Table 2 displays the incidence of adverse reactions in placebo-controlled trials for approved adult populations (i.e., MDD, GAD, DPNP, FM, OA, and CLBP) that occurred in 5% or more of duloxetine delayed-release capsules-treated patients and with an incidence greater than placebo-treated patients ... Somnolence e 10 3

Duloxetine can cause drowsiness (somnolence) in some patients, as evidenced by the incidence of somnolence in clinical trials.

  • The incidence of somnolence was 10% in duloxetine-treated patients compared to 3% in placebo-treated patients.
  • Somnolence was also reported as a reason for discontinuation in some patients. 2 2

From the Research

Duloxetine and Drowsiness

  • Duloxetine is known to cause drowsiness as a side effect, with studies indicating that somnolence is a common adverse event associated with its use 3, 4, 5.
  • The frequency of somnolence as an adverse event has been reported in various studies, with one study finding that it occurred in a significant number of patients treated with duloxetine 4.
  • The mechanism of duloxetine, as a serotonin-norepinephrine reuptake inhibitor, may contribute to its sedative effects, although the exact relationship between duloxetine and drowsiness is not fully understood 6, 7.
  • In clinical practice, patients taking duloxetine should be monitored for signs of drowsiness and advised to avoid operating heavy machinery or engaging in activities that require alertness 5.
  • The safety profile of duloxetine, including its potential to cause drowsiness, has been established in numerous studies, with most adverse events being mild to moderate in severity and not leading to discontinuation of treatment 3, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Duloxetine: A New Treatment for the Emotional and Physical Symptoms of Depression.

Primary care companion to the Journal of clinical psychiatry, 2003

Research

A retrospective pooled analysis of duloxetine safety in 23,983 subjects.

Current medical research and opinion, 2007

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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