Duloxetine side effects
Reading File
Finding Sources
Searching PubMed
duloxetine adverse effects
Reading File
Reading File
Reading File
Here is a structured summary of duloxetine's side effects based on multiple authoritative pharmacology and psychiatry textbooks.
Duloxetine - Side Effects
Mechanism Context
Duloxetine is an SNRI that inhibits reuptake of both serotonin and norepinephrine at all therapeutic doses. Many of its side effects stem directly from these two mechanisms - GI and sexual effects largely from serotonergic activity, while cardiovascular and autonomic effects (sweating, dry mouth, BP changes) relate more to noradrenergic activity.
Most Common Side Effects
| Side Effect | Reported Incidence |
|---|---|
| Nausea | ~22% - the leading cause of discontinuation |
| Dry mouth | ~16% |
| Fatigue | ~11% |
| Dizziness | ~11% |
| Somnolence (drowsiness) | ~8% |
| Constipation | Common |
| Sweating | Common |
| Sexual dysfunction | Comparable to SSRIs (true incidence uncertain) |
| Decreased appetite / anorexia | Common |
Incidence data from Kaplan & Sadock's Comprehensive Textbook of Psychiatry, p.9526
Cardiovascular Effects
- Blood pressure: Small but consistent increase in BP (~2 mmHg systolic, ~0.5 mmHg diastolic vs. placebo). Notably, this BP increase does not appear to be dose-dependent.
- Heart rate: Slight increase in resting pulse (~2 bpm).
- Unlike venlafaxine, duloxetine carries a lower risk of sustained hypertension (~1% above placebo).
Kaplan and Sadock's Synopsis of Psychiatry, p.1907; Kaplan & Sadock's Comprehensive Textbook, p.9527
Metabolic / Endocrine Effects
- Blood glucose and HbA1c: Duloxetine has been shown to increase blood sugar and HbA1c during long-term treatment. Close monitoring is recommended in patients with or at risk for diabetes.
Discontinuation Syndrome
- Abrupt discontinuation can trigger a discontinuation syndrome (dizziness, nausea, paresthesias, irritability, flu-like symptoms) - similar to venlafaxine.
- A gradual dose taper is always recommended when stopping.
Serious / Rare but Important Risks
- Hepatotoxicity: Duloxetine should be avoided in patients with substantial alcohol use or hepatic insufficiency due to potential liver effects. It is extensively hepatically metabolized.
- MAOI interaction: Potentially lethal serotonin syndrome if combined with MAOIs. A washout period is mandatory.
- Narrow-angle glaucoma: Contraindicated in uncontrolled narrow-angle glaucoma.
- Serotonin syndrome: Risk increases when combined with other serotonergic drugs.
Drug Interactions
- Duloxetine is a moderate inhibitor of CYP2D6, so it can raise plasma concentrations of drugs metabolized by CYP2D6 (e.g., antipsychotics, some TCAs).
- Duloxetine levels are reduced ~30% in smokers (CYP1A2 induction).
- Duloxetine levels are increased ~4-fold by potent CYP1A2 inhibitors (e.g., fluvoxamine, some fluoroquinolone antibiotics).
Special Populations
- Pregnancy/Nursing: Avoid unless benefits outweigh risks.
- Hepatic impairment: Avoid - drug is extensively liver-metabolized.
- End-stage renal disease: Avoid.
- Diabetes: Monitor closely - can worsen glycemic control.
Formulation Note
Duloxetine is formulated as a delayed-release capsule specifically to reduce the severity of nausea on absorption.
Sources: Lippincott Illustrated Reviews: Pharmacology; Kaplan & Sadock's Synopsis of Psychiatry; Kaplan & Sadock's Comprehensive Textbook of Psychiatry
Recent evidence note: A 2025 Lancet network meta-analysis (PMID 41135546) examining antidepressant effects on cardiometabolic parameters is consistent with the cardiovascular side effect profile described above - confirming that SNRIs like duloxetine carry modest but measurable cardiovascular signals worth monitoring in at-risk patients.
This is a shared conversation. Sign in to Orris to start your own chat.