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AtoMOXetine

Medically reviewed on Nov 15, 2018

Pronunciation

(AT oh mox e teen)

Index Terms

  • Atomoxetine Hydrochloride
  • LY139603
  • Methylphenoxy-Benzene Propanamine
  • Tomoxetine

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule, Oral:

Strattera: 10 mg, 18 mg

Strattera: 25 mg [contains fd&c blue #2 (indigotine)]

Strattera: 40 mg, 60 mg, 80 mg [contains corn starch, fd&c blue #2 (indigotine)]

Strattera: 100 mg [contains fd&c blue #2 (indigotine)]

Generic: 10 mg, 18 mg, 25 mg, 40 mg, 60 mg, 80 mg, 100 mg

Brand Names: U.S.

  • Strattera

Pharmacologic Category

  • Norepinephrine Reuptake Inhibitor, Selective

Pharmacology

Selectively inhibits the reuptake of norepinephrine (Ki 4.5 nM) with little to no activity at the other neuronal reuptake pumps or receptor sites.

Absorption

Rapid

Distribution

Vd: IV: 0.85 L/kg

Metabolism

Hepatic, via CYP2D6 and CYP2C19; forms metabolites (4-hydroxyatomoxetine, active, equipotent to atomoxetine; N-desmethylatomoxetine, limited activity); Note: CYP2D6 poor metabolizers have atomoxetine AUCs that are ~10-fold higher and peak concentrations that are ~fivefold greater than extensive metabolizers; 4-hyroxyatomoxetine plasma concentrations are very low (extensive metabolizers: 1% of atomoxetine concentrations; poor metabolizers: 0.1% of atomoxetine concentrations

Excretion

Urine (80%, as conjugated 4-hydroxy metabolite; <3% is excreted unchanged); feces (17%)

Time to Peak

Plasma: 1-2 hours; delayed 3 hours by high-fat meal

Duration of Action

Up to 24 hours (Jain 2017)

Half-Life Elimination

Atomoxetine: 5 hours (up to 24 hours in poor metabolizers); Active metabolites: 4-hydroxyatomoxetine: 6-8 hours; N-desmethylatomoxetine: 6-8 hours (34-40 hours in poor metabolizers)

Protein Binding

98%, primarily albumin

Special Populations: Renal Function Impairment

Extensive metabolizers with ESRD had higher systemic exposure (approximately a 65% increase), but there was no difference when exposure was corrected for mg/kg dose.

Special Populations: Hepatic Function Impairment

AUC is increased in extensive metabolizers with moderate or severe hepatic impairment.

Use: Labeled Indications

Attention-deficit/hyperactivity disorder: Treatment of attention-deficit/hyperactivity disorder (ADHD)

Contraindications

Hypersensitivity to atomoxetine or any component of the formulation; use with or within 14 days of MAO inhibitors; narrow-angle glaucoma; current or history of pheochromocytoma; severe cardiac or vascular disorders in which the condition would be expected to deteriorate with clinically important increases in blood pressure (eg, 15 to 20 mm Hg) or heart rate (eg, 20 beats/minute).

Canadian labeling: Additional contraindications (not in US labeling): Symptomatic cardiovascular diseases, moderate to severe hypertension; advanced arteriosclerosis; uncontrolled hyperthyroidism

Dosing: Adult

Attention-deficit/hyperactivity disorder (ADHD) treatment: Oral: Note: Atomoxetine may be discontinued without tapering.

Initial: 40 mg/day, increase after minimum of 3 days to 80 mg/day; may administer as a single daily dose in the morning or as 2 evenly divided doses in the morning and late afternoon/early evening. May increase (if optimal response has not been achieved) to 100 mg/day after an additional 2 to 4 weeks. Maximum: 100 mg/day.

Dosage adjustment in patients receiving strong CYP2D6 inhibitors (eg, paroxetine, fluoxetine, quinidine) or patients known to be CYP2D6 poor metabolizers: Initial: 40 mg/day; if tolerating therapy but inadequate response, may increase after minimum of 4 weeks to 80 mg/day.

Dosing: Geriatric

Use has not been evaluated in the elderly.

Dosing: Pediatric

ADHD treatment: Oral: Note: Atomoxetine may be discontinued without tapering.

Children ≥6 years and Adolescents ≤70 kg:

Initial: ~0.5 mg/kg/day, increase after minimum of 3 days to ~1.2 mg/kg/day; may administer as a single daily dose in the morning or as 2 evenly divided doses in the morning and late afternoon/early evening. Maximum dose: 1.4 mg/kg/day or 100 mg/day, whichever is less. Note: Doses >1.2 mg/kg/day have not been shown to provide additional benefit.

Dosage adjustment in patients receiving strong CYP2D6 inhibitors (eg, paroxetine, fluoxetine, quinidine) or patients known to be CYP2D6 poor metabolizers: Initial: 0.5 mg/kg/day; if tolerating therapy but inadequate response, may increase after minimum of 4 weeks to 1.2 mg/kg/day.

Children ≥6 years and Adolescents >70 kg: Refer to adult dosing.

Dosing: Renal Impairment

No dosage adjustment necessary.

Dosing: Hepatic Impairment

Mild impairment (Child-Pugh class A): No dosage adjustment provided in manufacturer’s labeling.

Moderate impairment (Child-Pugh class B): All doses should be reduced to 50% of normal.

Severe impairment (Child-Pugh class C): All doses should be reduced to 25% of normal.

Administration

Oral: Administer without regard to food. Do not crush, chew, or open capsule; swallow whole. Note: Atomoxetine is an ocular irritant; if capsule is opened inadvertently and contents come into contact with eye, flush eye immediately with water and obtain medical advice; wash hands and any potentially contaminated surface as soon as possible.

Storage

Store at 25°C (77°F); excursions are permitted between 15°C and 30°C (59°F and 86°F).

Drug Interactions

Abiraterone Acetate: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Management: Avoid concurrent use of abiraterone with CYP2D6 substrates that have a narrow therapeutic index whenever possible. When concurrent use is not avoidable, monitor patients closely for signs/symptoms of toxicity. Consider therapy modification

Ajmaline: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Asunaprevir: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Consider therapy modification

Beta2-Agonists: AtoMOXetine may enhance the tachycardic effect of Beta2-Agonists. Monitor therapy

Cobicistat: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

CYP2D6 Inhibitors (Moderate): May decrease the metabolism of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

CYP2D6 Inhibitors (Strong): May increase the serum concentration of AtoMOXetine. Management: Initiate atomoxetine at a reduced dose (adult doses -- patients up to 70kg: 0.5mg/kg/day; patients 70kg or more: 40mg/day) in patients receiving a strong CYP2D6 inhibitor. Consider therapy modification

Dacomitinib: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Management: Avoid concurrent use of dacomitinib with CYP2D6 subtrates that have a narrow therapeutic index. Consider therapy modification

Darunavir: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Imatinib: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Iobenguane Radiopharmaceutical Products: Selective Norepinephrine Reuptake Inhibitors may diminish the therapeutic effect of Iobenguane Radiopharmaceutical Products. Management: Discontinue all drugs that may inhibit or interfere with catecholamine transport or uptake for at least 5 biological half-lives before iobenguane administration. Do not administer these drugs until at least 7 days after each iobenguane dose. Avoid combination

Lumefantrine: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Monoamine Oxidase Inhibitors: May enhance the neurotoxic (central) effect of AtoMOXetine. Avoid combination

Panobinostat: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Peginterferon Alfa-2b may increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Perhexiline: CYP2D6 Substrates (High risk with Inhibitors) may increase the serum concentration of Perhexiline. Perhexiline may increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

QT-prolonging Agents (Highest Risk): QT-prolonging Agents (Indeterminate Risk - Caution) may enhance the QTc-prolonging effect of QT-prolonging Agents (Highest Risk). Management: Monitor for QTc interval prolongation and ventricular arrhythmias when these agents are combined. Patients with additional risk factors for QTc prolongation may be at even higher risk. Monitor therapy

QuiNINE: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Sympathomimetics: AtoMOXetine may enhance the hypertensive effect of Sympathomimetics. AtoMOXetine may enhance the tachycardic effect of Sympathomimetics. Monitor therapy

Adverse Reactions

Percentages as reported in children and adults; some adverse reactions may be increased in "poor metabolizers" (CYP2D6). Frequency not always defined.

>10%:

Central nervous system: Headache (19%; children and adolescents), insomnia (1% to 19%), drowsiness (8% to 11%)

Dermatologic: Hyperhidrosis (4% to 15%)

Gastrointestinal: Xerostomia (17% to 35%), nausea (7% to 26%), decreased appetite (15% to 23%), abdominal pain (7% to 18%), vomiting (4% to 11%), constipation (1% to 11%)

Genitourinary: Erectile dysfunction (8% to 21%)

1% to 10%:

Cardiovascular: Increased diastolic blood pressure (5% to 9%; ≥15 mm Hg), systolic hypertension (4% to 5%), palpitations (3%), cold extremities (1% to 3%), syncope (≤3%), flushing (≥2%), orthostatic hypotension (≤2%), tachycardia (≤2%), prolonged Q-T interval on ECG

Central nervous system: Fatigue (6% to 10%), dizziness (5% to 8%), depression (4% to 7%), disturbed sleep (3% to 7%), irritability (5% to 6%), jitteriness (2% to 5%), abnormal dreams (4%), chills (3%), paresthesia (adults 3%; postmarketing observation in children), anxiety (≥2%), hostility (children and adolescents 2%), emotional lability (1% to 2%), agitation, restlessness, sensation of cold

Dermatologic: Excoriation (2% to 4%), skin rash (2%), pruritus, urticaria

Endocrine & metabolic: Weight loss (2% to 7%), decreased libido (3%), hot flash (3%), increased thirst (2%), menstrual disease

Gastrointestinal: Dyspepsia (4%), anorexia (3%), dysgeusia, flatulence

Genitourinary: Ejaculatory disorder (2% to 6%), urinary retention (1% to 6%), dysmenorrhea (3%), dysuria (2%), orgasm abnormal, pollakiuria, prostatitis, testicular pain, urinary frequency

Neuromuscular & skeletal: Tremor (1% to 5%), muscle spasm, weakness

Ophthalmic: Blurred vision (1% to 4%), conjunctivitis (1% to 3%), mydriasis

Respiratory: Pharyngolaryngeal pain

Miscellaneous: Therapeutic response unexpected (2%)

<1%, postmarketing, and/or case reports: Aggressive behavior, akathisia, alopecia, anaphylaxis, angioedema, cerebrovascular accident, change in libido, delusions, growth suppression (children), hallucination, hepatotoxicity, hypersensitivity reaction, hypoesthesia, hypomania, impulsivity, jaundice, lethargy, mania, myocardial infarction, panic attack, pelvic pain, priapism, Raynaud's phenomenon, rhabdomyolysis, seizure (including patients with no prior history or known risk factors for seizure), severe hepatic disease, suicidal ideation, tics

ALERT: U.S. Boxed Warning

Suicidal ideation in children and adolescents:

Atomoxetine increased the risk of suicidal ideation in short-term studies in children or adolescents with attention deficit hyperactivity disorder (ADHD). Anyone considering the use of atomoxetine in a child or adolescent must balance this risk with the clinical need. Comorbidities occurring with ADHD may be associated with an increase in the risk of suicidal ideation and/or behavior. Closely monitor patients who are started on therapy for suicidality (suicidal thinking and behavior), clinical worsening, or unusual changes in behavior. Advise families and caregivers of the need for close observation and communication with the prescribing health care provider. Atomoxetine is approved for ADHD in pediatric and adult patients. Atomoxetine is not approved for major depressive disorder (MDD).

Pooled analyses of short-term (6- to 18-week), placebo-controlled trials of atomoxetine in children and adolescents (12 trials involving more than 2,200 patients, including 11 trials in ADHD and 1 trial in enuresis) have revealed a greater risk of suicidal ideation early during treatment in those receiving atomoxetine compared with placebo. The average risk of suicidal ideation in patients receiving atomoxetine was 0.4% compared with none in placebo-treated patients. No suicides occurred in these trials.

Warnings/Precautions

Concerns related to adverse effects:

• Aggressive behavior: New or worsening symptoms of hostility or aggressive behaviors have been associated with atomoxetine, particularly with the initiation of therapy.

• Allergic reactions: Anaphylactic reactions, angioneurotic edema, urticaria, and rash may occur (rare).

• Altered cardiac conduction: In clinical trials at therapeutic doses, atomoxetine consistently did not prolong the QT/QTc interval; however, one placebo-controlled study in healthy CYP2D6 poor metabolizers demonstrated a statistically significant increase in QTc with increasing atomoxetine concentrations (Loghin 2013; Martinez-Raga 2013). Case reports suggest that atomoxetine overdose may increase the QT interval; however, this occurred when atomoxetine was combined with other agents known to have QT prolongation potential or inhibit CYP2D6 (Barker 2004; Sawant 2004). Atomoxetine, at high concentrations ex vivo, has demonstrated hERG channel block (Scherer 2009).

• Cardiovascular events: Atomoxetine has been associated with serious cardiovascular events including sudden death in children and adolescents and sudden death, stroke, and MI in adult patients with preexisting structural cardiac abnormalities or other serious heart problems. Atomoxetine should be avoided in patients with known serious structural cardiac abnormalities, cardiomyopathy, serious heart rhythm abnormalities, coronary artery disease, or other serious cardiac problems that could increase the risk of sudden death that these conditions alone carry. Prior to initiating atomoxetine, assess medical history and family history of sudden death or ventricular arrhythmia; conduct a physical exam to assess for cardiac disease; patients should receive further evaluation if findings suggest cardiac disease, such as ECG and echocardiogram. Promptly conduct cardiac evaluation in patients who develop exertional chest pain, unexplained syncope, or any other symptoms of cardiac disease during atomoxetine treatment.

• Hepatotoxicity: Use may be associated with rare but severe liver injury, including hepatic failure; monitor liver enzymes upon any sign or symptom of liver dysfunction (eg, pruritus, dark urine, jaundice, right upper quadrant tenderness, unexplained flu-like symptoms); discontinue and do not restart in patients with jaundice or laboratory evidence of liver injury. The majority of reported cases occurred within 120 days of initiation of therapy.

• Priapism: Prolonged (>4 hours), painful, and nonpainful penile erections have been reported (rarely) in pediatric and adult patients. There are 3 published reports in boys ages 11 to 12 years (Armstrong 2015; Goetz 2014; Wadoo 2009), only one of whom was solely taking atomoxetine; another of the 3 was attributed to risperidone. Despite at least 22 cases involving methylphenidate (Baytunca 2016; Bozkurt 2017; Chauhan 2016; Eiland 2014; Esnafoglu 2017; Mann 2017; Unver 2017), a 2013 FDA warning states priapism appears to be more common in patients taking atomoxetine than in patients taking methylphenidate. In reports involving methylphenidate, amphetamines, or atomoxetine, priapism has been reported with different formulations, doses, following dose changes, and during periods of withdrawal. Patients with certain hematological dyscrasias (eg, sickle cell disease), malignancies, perineal trauma, or concomitant use of alcohol, illicit drugs, or other medications associated with priapism may be at increased risk (Eiland 2014). Patients who develop abnormally sustained or frequent and painful erections should discontinue therapy and seek immediate medical attention. In patients with severe cases of priapism that were slow to resolve and/or required detumescence by aspiration, avoidance of stimulants and atomoxetine may be preferred (Eiland 2014).

• Psychiatric effects: Treatment-emergent psychotic or manic symptoms (eg, hallucinations, delusional thinking, mania) may occur in children and adolescents without a prior history of psychotic illness or mania. Consider discontinuation of treatment if symptoms occur.

Disease-related concerns:

• ADHD and comorbidities: Randomized, controlled trials have demonstrated that atomoxetine does not worsen anxiety in patients with existing anxiety disorders or tics related to Tourette disorder.

• Bipolar disorder: Use caution in patients with comorbid bipolar disorder; therapy may induce mixed/manic episodes. Atomoxetine is not approved for major depressive disorder; patients presenting with depressive symptoms should be screened for bipolar disorder.

• Cardiovascular disorders: Atomoxetine may increase BP and heart rate (HR); most pediatric patients may experience a moderate increase in BP and/or HR; a large, pooled analysis reported more pronounced increases in BP (≥15 to 20 mm Hg) and HR (≥20 bpm) in 8% to 12% of pediatric patients (Reed 2016). CYP2D6 poor metabolizers may experience greater increases in BP and HR. Use with caution in patients with underlying conditions (eg, hypertension, tachycardia, cardiovascular or cerebrovascular disease) that could be worsened by BP or HR increases and in patients predisposed to hypotension or with conditions associated with abrupt HR or BP changes. Avoid use in patients with severe cardiac or vascular disorders that would be expected to deteriorate with clinically significant increases in BP.

• Hepatic impairment: Use with caution in patients with hepatic impairment; dosage adjustments necessary in moderate and severe hepatic insufficiency.

• Urinary retention: Use with caution in patients with a history of urinary retention or bladder outlet obstruction; may cause urinary retention/hesitancy.

Special populations:

• CYP2D6 poor metabolizers: Dosage adjustments are recommended in CYP2D6 poor metabolizers; these patients have increased exposure to atomoxetine.

• Pediatric: [US Boxed Warning]: Use with caution in pediatric patients; may be an increased risk of suicidal ideation. Closely monitor for clinical worsening, suicidality, or unusual changes in behavior; especially during the initial few months of a course of drug therapy, or at times of dose changes, either increases or decreases. The family or caregiver should be instructed to closely observe the patient and communicate condition with health care provider. Growth should be monitored during treatment. Height and weight gain may be reduced during the first 9 to 12 months of treatment, but should recover by 3 years of therapy.

Other warnings/precautions:

• ADHD treatment: Appropriate use: Recommended to be used as part of a comprehensive treatment program for attention deficit disorders.

Monitoring Parameters

Liver enzymes (upon signs/symptoms of liver dysfunction and for several weeks after discontinuation for liver dysfunction); blood pressure and pulse (baseline, following dose increases and periodically during treatment); growth (weight and height) and appetite in children; medical and family history of sudden death or ventricular arrhythmia (before initiation); physical exam to assess for cardiac disease (at baseline or if symptoms of cardiac disease develop during treatment) with further work-up (ECG and echocardiogram) if exam findings suggest cardiac disease; behavior changes (daily, particularly during initial months of therapy or at times of dose changes)

Pregnancy Risk Factor

C

Pregnancy Considerations

Adverse events have been observed in animal reproduction studies. Information related to atomoxetine use in pregnancy is limited; appropriate contraception is recommended for sexually active women of childbearing potential (Heiligenstein, 2003).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience abdominal pain, insomnia, nausea, vomiting, lack of appetite, dry mouth, constipation, loss of strength and energy, or fatigue. Have patient report immediately to prescriber signs of depression (suicidal ideation, anxiety, emotional instability, or confusion), signs of liver problems (dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or jaundice), vision changes, behavioral changes, irritability, agitation, panic attacks, hallucinations, tachycardia, abnormal heartbeat, severe headache, difficult urination, sexual dysfunction, priapism, signs of severe cerebrovascular disease (change in strength on one side is greater than the other, difficulty speaking or thinking, change in balance, or vision changes), angina, shortness of breath, severe dizziness, or passing out (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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