Side Effects of Strattera (Atomoxetine)
Strattera (atomoxetine) has several common side effects including dry mouth, nausea, decreased appetite, constipation, dizziness, insomnia, somnolence, sexual dysfunction, and increased blood pressure and heart rate. 1
Common Side Effects
Atomoxetine's side effect profile differs from stimulant medications used for ADHD. The most common side effects include:
Gastrointestinal Effects
- Dry mouth (particularly common in adults)
- Nausea and vomiting
- Abdominal pain/discomfort
- Constipation
- Decreased appetite and weight loss
Neurological Effects
- Dizziness
- Headache
- Somnolence/sedation
- Fatigue
- Tremor
- Paresthesia (tingling sensations)
Psychiatric Effects
- Insomnia
- Mood swings
- Irritability
- Abnormal dreams
- Sleep disorders
Cardiovascular Effects
- Increased heart rate
- Increased blood pressure
- Palpitations
- Hot flushes
Urogenital Effects
- Urinary hesitation/retention
- Dysuria (painful urination)
- Sexual dysfunction (particularly in adults)
- Erectile dysfunction
- Ejaculation disorders
- Decreased libido
Other Effects
- Hyperhidrosis (excessive sweating)
- Chills
- Peripheral coldness
- Fatigue
Serious but Less Common Side Effects
Atomoxetine carries several warnings for potentially serious adverse effects:
Suicidal Ideation
The FDA has issued a black box warning for increased risk of suicidal ideation in children and adolescents taking atomoxetine 1.
Liver Injury
Rare cases of serious liver injury have been reported, presenting with:
- Abdominal pain
- Hepatomegaly (enlarged liver)
- Elevated liver enzymes
- Jaundice
Cardiovascular Effects
- Sustained clinical hypertension
- Significant increases in blood pressure and heart rate
Severe Skin Reactions
- Erythema multiforme
- Stevens-Johnson syndrome
Seizures
Atomoxetine has been associated with seizures in rare cases, particularly in overdose situations 2.
Special Considerations
Pregnancy and Breastfeeding
- Limited data on pregnancy, but atomoxetine does not appear to be associated with major congenital malformations 3
- Caution advised during breastfeeding as atomoxetine likely passes into breast milk 3
CYP2D6 Poor Metabolizers
Patients who are poor metabolizers of CYP2D6 (approximately 7% of the population) may experience:
- Higher plasma levels of atomoxetine
- More pronounced side effects
- Different side effect profile including:
- Vision blurred
- Constipation
- Feeling jittery
- Tremor
- Sleep disorders
- Urinary retention
- Sexual dysfunction
- Hyperhidrosis 1
Drug Interactions
- Concomitant use with MAOIs is contraindicated due to risk of serotonin syndrome
- Medications that inhibit CYP2D6 (like certain SSRIs) can increase atomoxetine levels 4
Monitoring Recommendations
- Regular monitoring of heart rate and blood pressure
- Height and weight monitoring in children
- Monitoring for signs of suicidal ideation, particularly when starting treatment
- Monitoring for signs of liver injury (jaundice, right upper quadrant pain)
- Monitoring for peripheral vascular symptoms, especially in CYP2D6 poor metabolizers 4
Management of Side Effects
- Most side effects are mild to moderate and often improve with time
- Dose adjustments may help manage side effects
- Taking with food can reduce gastrointestinal side effects
- Atomoxetine should be discontinued immediately if signs of liver injury, severe skin reactions, or significant cardiovascular effects occur 1
Atomoxetine has a different side effect profile compared to stimulant medications, with less risk of insomnia but more risk of somnolence, and carries no risk of abuse or diversion 5, 6.