Reviewed on 9/2/2021

What Is Atomoxetine and How Does It Work?

Atomoxetine is used to treat attention-deficit hyperactivity disorder (ADHD) as part of a total treatment plan, including psychological, social, and other treatments. Atomoxetine may help to increase the ability to pay attention, concentrate, stay focused, and stop fidgeting. It is thought to work by restoring the balance of certain natural substances (neurotransmitters) in the brain.

  • Atomoxetine is available under the following different brand names: Strattera.

What Are Dosages of Atomoxetine?

Dosages of Atomoxetine:

Dosage Forms and Strengths


  • 10 mg
  • 18 mg
  • 25 mg
  • 40 mg
  • 60 mg
  • 80 mg
  • 100 mg

Dosage Considerations – Should be Given as Follows:

Attention-Deficit/Hyperactivity Disorder

  • Adult: 40 mg orally once daily initially; increased after 3 days or more to 80 mg orally once daily or divided every 12 hours; may be increased to up to 100 mg if optimal response is not achieved
  • Dosing considerations
    • When drug is coadministered with strong CYP2D6 inhibitors (e.g., paroxetine, fluoxetine, quinidine) or used in patients known to be poor CYP2D6 metabolizers, decrease dosage; initiate with 40 mg/day, but do not exceed 80 mg/day
  • Pediatric:
    • Children over 6 years and up to 70 kg: 0.5 mg/kg orally once daily; increased after 3 days or more to target dosage of approximately 1.2 mg/kg orally once daily or divided every 12 hours; total daily dose not to exceed 1.4 mg/kg or 100 mg, whichever is less; no benefit observed with higher doses
    • Greater than 70 kg: 40 mg orally once daily initially; increased after 3 days or more to 80 mg orally once daily or divided every 12 hours; if necessary, may be increased after 2-4 additional weeks to 100 mg orally once daily
  • Dosing considerations
    • When drug is coadministered with strong CYP2D6 inhibitors (e.g., paroxetine, fluoxetine, quinidine) or used in patients known to be poor CYP2D6 metabolizers, decrease dosage
    • Up to 70 kg: 0.5 mg/kg/day initially; increased to usual target dosage of 1.2 mg/kg/day only if symptoms fail to improve after 4 weeks and initial dosage is well tolerated
    • Greater than 70 kg: 40 mg/day initially; not to exceed 80 mg/day

Dosing Modifications

  • Renal impairment: Dosage adjustment not necessary
  • Mild hepatic impairment (Child-Pugh class A): Dosage adjustment not necessary
  • Moderate hepatic impairment (Child-Pugh class B): Decrease initial and target dosage by 50%
  • Severe hepatic impairment (Child-Pugh class C): Decrease initial and target dosage by 75%


  • Must be swallowed whole with aid of liquids; must not be chewed, divided, or crushed
  • Administer once daily in morning, with or without food

Limitation of Use

  • In obstructive sleep apnea, indicated to treat excessive sleepiness and not as treatment for the underlying obstruction


ADHD Symptoms in Children See Slideshow

What Are Side Effects Associated with Using Atomoxetine?

Common side effects of atomoxetine include:

Serious side effects of atomoxetine include:

  • Difficulty urinating
  • Unusually fast or irregular heartbeat
  • Fainting
  • Numbness or tingling

Postmarketing side effects of atomoxetine reported include:

  • QT prolongation, fainting
  • Raynaud's phenomenon
  • Lethargy
  • Reduced sense of touch, numbness, and tingling in children and adolescents, sensory disturbances, tics
  • Depression and depressed mood, anxiety
  • Cases include patients with preexisting seizure disorders and those with identified risk factors for seizures, as well as patients with neither history of nor identified risk factors for seizures; exact relation between atomoxetine and seizures is difficult to evaluate because of uncertainty about background risk of seizures in patients with attention-deficit/hyperactivity disorder (ADHD)
  • Excess sweating
  • Male pelvic pain, urinary hesitation or retention in children and adolescents
  • Muscle wasting (rhabdomyolysis)

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Atomoxetine?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Severe interactions of atomoxetine include:
  • Atomoxetine has no known serious interactions with other drugs.
  • Atomoxetine has moderate interactions with at least 54 different drugs.
  • Atomoxetine has no known mild interactions with other drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine.

What Are Warnings and Precautions for Atomoxetine?


Atomoxetine use has been associated with an increased risk of suicidal ideation in short-term studies in children or adolescents with ADHD; this risk must be balanced against clinical needs in patients with ADHD.

Monitor patients closely for suicidal thinking and behavior, clinical worsening, or unusual behavioral changes; families and caregivers should be advised of the need for close observation and communication with prescribing healthcare provider.

The average risk of suicidal ideation in patients receiving atomoxetine is approximately 0.4% (5/1357 patients).

This medication contains atomoxetine. Do not take Strattera if you are allergic to atomoxetine or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Hypersensitivity
  • Narrow-angle glaucoma
  • Administration concomitantly with or within 14 days of monoamine oxidase inhibitor (MAOI) therapy; risk of potentially fatal reaction, including hyperthermia, myoclonus, altered mental status, and neuroleptic malignant syndrome (NMS)-like symptoms
  • Pheochromocytoma: Serious reactions, including elevated blood pressure and tachyarrhythmia, have been reported in patients with current or previous pheochromocytoma
  • Severe cardiovascular disorders where the condition would deteriorate because blood pressure increases by 15-20 mm Hg or heart rate increases by 20 beats/minute; risk is greater in poor CYP2D6 metabolizers

Effects of Drug Abuse

  • No information available

Short-Term Effects

  • See "What Are Side Effects Associated with Using Atomoxetine?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Atomoxetine?"


  • If the drug is given concomitantly with CYP2D6 inhibitor, wait 4 weeks after initiation before adjusting the dosage
  • Liver injury reported within 120 days of initiation of atomoxetine; patients may present with elevated liver enzymes (greater than 20 times upper limit of normal [ULN]) and yellowing skin and eyes (jaundice) with significantly elevated bilirubin levels (greater than 2 times ULN), followed by recovery upon discontinuance of atomoxetine
  • Low blood pressure and dizziness on standing (orthostatic hypotension) and fainting (syncope) reported
  • Risk of suicidal thoughts in children and adolescents
  • Small risk of an allergic reaction
  • Use caution in high blood pressure (hypertension), fast heart rate (tachycardia) (see Contraindications)
  • Sudden deaths, stroke, and heart attack (myocardial infarction) reported in patients with structural cardiac abnormalities or other serious heart problems taking stimulants at usual doses; patients should have a careful history and physical exam to assess for the presence of cardiovascular disease; consider not using atomoxetine in adults with clinically significant cardiac abnormalities
  • Patients who develop symptoms such as exertional chest pain, unexplained syncope, or other symptoms suggestive of cardiac disease during stimulant treatment should undergo a prompt cardiac evaluation
  • Particular care should be taken in using stimulants to treat ADHD patients with comorbid bipolar disorder because of concern for possible induction of mixed/manic episodes in such patients
  • Aggressive behavior or hostility is often observed in children and adolescents with ADHD; monitor for the appearance of or worsening of aggressive behavior or hostility
  • Monitor growth of children ages 7 to 10 years during treatment with stimulants; may need to interrupt therapy in patients not growing or gaining weight as expected
  • Urinary hesitancy or sexual dysfunction may occur
  • Rare instances of priapism reported, sometimes necessitating surgical intervention; typically not reported during initiation but often occurring after dosage increase; immediate medical attention should be sought for abnormally sustained or frequent and painful erections
  • The drug can be discontinued without being tapered
  • Hypesthesia, paresthesia in children and adolescents, sensory disturbances
  • Rare reports of allergic reactions, including anaphylactic reactions, angioneurotic swelling (edema), hives, and rash
  • Use with caution in patients with bipolar disorder, history of hypertension, hepatic impairment, existing anxiety disorder, history of urinary retention, or tics related to Tourette disorder

Pregnancy and Lactation

  • Use atomoxetine with caution during pregnancy if the benefits outweigh the risks. Animal studies show risk and human studies are not available or neither animal nor human studies were done.
  • It is unknown whether atomoxetine is excreted in the milk; use with caution if breastfeeding.


The abbreviated term ADHD denotes the condition commonly known as: See Answer
Medscape. Atomoxetine.
RxList. Strattera Side Effects Center.

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