Side Effects of Cymbalta (Duloxetine)
Cymbalta (duloxetine) has numerous side effects, with the most common being nausea, dry mouth, sleepiness, fatigue, constipation, decreased appetite, increased sweating, and dizziness. 1
Common Side Effects
Duloxetine commonly causes the following side effects:
Gastrointestinal effects:
- Nausea (most common reason for discontinuation)
- Dry mouth
- Constipation
- Decreased appetite
- Diarrhea
- Vomiting
Neurological effects:
- Sleepiness/somnolence/sedation
- Fatigue
- Dizziness
- Headache
- Tremor
Other common effects:
- Increased sweating (hyperhidrosis)
- Sexual dysfunction
- Insomnia or sleep disturbances
Serious Side Effects
Duloxetine may cause several serious adverse effects that require immediate medical attention:
Liver damage - Watch for:
- Itching
- Right upper abdominal pain
- Dark urine
- Yellow skin or eyes
- Enlarged liver
- Increased liver enzymes 1
Blood pressure changes and falls:
- May increase blood pressure
- May cause orthostatic hypotension (decreased blood pressure when standing)
- Increased risk of falls, especially in elderly patients 1
Serotonin syndrome (potentially life-threatening):
- Agitation, hallucinations, coma
- Coordination problems or muscle twitching
- Racing heartbeat, blood pressure changes
- Sweating, fever
- Nausea, vomiting, diarrhea
- Muscle rigidity
- Seizures 1
Abnormal bleeding:
- Especially when taken with blood thinners, NSAIDs, or aspirin 1
Severe skin reactions:
- Skin blisters, peeling rash
- Sores in the mouth
- Hives or allergic reactions 1
Discontinuation syndrome if stopped abruptly:
- Anxiety, irritability
- Fatigue or sleep problems
- Headache, dizziness
- Electric shock-like sensations
- Gastrointestinal symptoms 1
Manic episodes:
- Greatly increased energy
- Racing thoughts
- Reckless behavior
- Unusual grandiosity
- Excessive happiness or irritability
- Rapid or excessive talking 1
Visual problems:
- Eye pain
- Vision changes
- Swelling or redness around the eye 1
Seizures or convulsions 1
Low sodium levels:
- More common in elderly patients
- Symptoms include headache, weakness, confusion, and memory problems 1
Urination problems:
- Decreased urine flow
- Inability to urinate 1
Special Populations
Children and Adolescents
- Common side effects include nausea, decreased weight, and dizziness
- Growth (height and weight) should be monitored during treatment
- May cause weight loss (16% experienced clinically significant decrease) 1
Elderly Patients
- More susceptible to falls, orthostatic hypotension, and sodium imbalances
- May be more sensitive to side effects at standard doses 2, 1
Post-Marketing Reports
Additional adverse reactions reported after market introduction include:
- Acute pancreatitis
- Anaphylactic reactions
- Aggression and anger (particularly early in treatment or after discontinuation)
- Angioneurotic edema
- Angle-closure glaucoma
- Colitis
- Cutaneous vasculitis
- Extrapyramidal disorder
- Galactorrhea
- Gynecological bleeding
- Hallucinations
- Hyperglycemia
- Hyperprolactinemia
- Hypertensive crisis
- Muscle spasm
- Rash
- Restless legs syndrome
- Seizures upon treatment discontinuation
- Supraventricular arrhythmia
- Tinnitus (upon treatment discontinuation)
- Trismus
- Urticaria 1
Precautions When Taking Duloxetine
- Do not take with MAOIs or within 14 days of stopping an MAOI
- Use caution with other serotonergic drugs (risk of serotonin syndrome)
- Avoid heavy alcohol use (risk of severe liver injury)
- Do not drive or operate machinery until effects are known
- Do not stop taking abruptly (taper gradually to avoid discontinuation syndrome)
- Monitor blood pressure regularly
- Use caution in patients with a history of seizures or bipolar disorder 1
Duloxetine's side effect profile should be carefully considered when prescribing, with particular attention to the patient's age, comorbidities, and other medications to minimize adverse effects and maximize therapeutic benefit.