Atomoxetine Drug Information

Acute Treatment Dosing of children and adolescents up to 70 kg body weight - Atomoxetine capsules should be initiated at a total daily dose of approximately 0.5 mg/kg and increased after a minimum of 3 days to a target total daily dose of approximately 1.2 mg/kg administered either as a single daily dose in the morning or as evenly divided doses in the morning and late afternoon/early evening. No additional benefit has been demonstrated for doses higher than 1.2 mg/kg/day. The total daily dose in children and adolescents should not exceed 1.4 mg/kg or 100 mg, whichever is less.

After 2 to 4 additional weeks, the dose may be increased to a maximum of 100 mg in patients who have not achieved an optimal response. There are no data that support increased effectiveness at higher doses. The maximum recommended total daily dose in children and adolescents over 70 kg and adults is 100 mg.

Maintenance/Extended Treatment It is generally agreed that pharmacological treatment of ADHD may be needed for extended periods. The benefit of maintaining pediatric patients (ages 6 to 15 years) with ADHD on atomoxetine capsules after achieving a response in a dose range of 1.2 to 1.8 mg/kg/day was demonstrated in a controlled trial. Patients assigned to atomoxetine capsules in the maintenance phase were generally continued on the same dose used to achieve a response in the open label phase.

The physician who elects to use atomoxetine capsules for extended periods should periodically reevaluate the long-term usefulness of the drug for the individual patient.

General Dosing Information

Atomoxetine capsules may be taken with or without food. Atomoxetine capsules can be discontinued without being tapered. Atomoxetine capsules are not intended to be opened, they should be taken whole.

The safety of single doses over 120 mg and total daily doses above 150 mg have not been systematically evaluated.

Dosing in Specific Populations

Dosing adjustment for hepatically impaired patients — For those ADHD patients who have hepatic insufficiency (HI), dosage adjustment is recommended as follows: For patients with moderate HI (Child-Pugh Class B), initial and target doses should be reduced to 50% of the normal dose (for patients without HI). For patients with severe HI (Child-Pugh Class C), initial dose and target doses should be reduced to 25% of normal. Dosing adjustment for use with a strong CYP2D6 inhibitor or in patients who are known to be CYP2D6 PMs — In children and adolescents up to 70 kg body weight administered strong CYP2D6 inhibitors, e.g., paroxetine, fluoxetine, and quinidine, or in patients who are known to be CYP2D6 PMs, atomoxetine capsule should be initiated at 0.5 mg/kg/day and only increased to the usual target dose of 1.2 mg/kg/day if symptoms fail to improve after 4 weeks and the initial dose is well tolerated.

Clinical Trials Experience Atomoxetine was administered to 5382 children or adolescent patients with ADHD and 1007 adults with ADHD in clinical studies. Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Child and Adolescent Clinical Trials Reasons for discontinuation of treatment due to adverse reactions in child and adolescent clinical trials — In acute child and adolescent placebo-controlled trials, 3.0% (48/1613) of atomoxetine subjects and 1.4% (13/945) placebo subjects discontinued for adverse reactions.

For all studies, (including open-label and long-term studies), 6.3% of extensive metabolizer (EM) patients and 11.2% of poor metabolizer (PM) patients discontinued because of an adverse reaction. Seizures — Atomoxetine has not been systematically evaluated in pediatric patients with seizure disorder as these patients were excluded from clinical studies during the product’s premarket testing. Commonly observed adverse reactions in acute child and adolescent, placebo-controlled trials - Commonly observed adverse reactions associated with the use of atomoxetine (incidence of 2% or greater) and not observed at an equivalent incidence among placebo-treated patients (atomoxetine incidence greater than placebo) are listed in Table 2.

Results were similar in the BID and the QD trial except as shown in Table 3, which shows both BID and QD results for selected adverse reactions based on statistically significant Breslow-Day tests. The most commonly observed adverse reactions in patients treated with atomoxetine (incidence of 5% or greater and at least twice the incidence in placebo patients, for either BID or QD dosing) were: nausea, vomiting, fatigue, decreased appetite, abdominal pain, and somnolence ( see Tables 2 and 3). Table 2: Common Treatment-Emergent Adverse Reactions Associated with the Use of Atomoxetine in Acute up to 2 1 a Reactions reported by at least 2% of patients treated with atomoxetine, and greater than placebo.

The following reactions did not meet this criterion but were reported by more atomoxetine-treated patients than placebo-treated patients and are possibly related to atomoxetine treatment: blood pressure increased, early morning awakening (terminal insomnia), flushing, mydriasis, sinus tachycardia, asthenia, palpitations, mood swings, constipation, and dyspepsia. The following reactions were reported by at least 2% of patients treated with atomoxetine, and equal to or less than placebo: pharyngolaryngeal pain, insomnia (insomnia includes the terms, insomnia, initial insomnia, middle insomnia). The following reaction did not meet this criterion but shows a statistically significant dose relationship: pruritus. b Abdominal pain includes the terms: abdominal pain upper, abdominal pain, stomach discomfort, abdominal discomfort, epigastric discomfort. c Somnolence includes the terms: sedation, somnolence.

Table 3: Common Treatment-Emergent Adverse Reactions Associated with the Use of Atomoxetine in Acute up to a Abdominal pain includes the terms: abdominal pain upper, abdominal pain, stomach discomfort, abdominal discomfort, epigastric discomfort. b Constipation didn’t meet the statistical significance on Breslow-Day test but is included in the table because of pharmacologic plausibility. c Mood swings didn’t meet the statistical significance on Breslow-Day test at 0.05 level but p-value was <0.1 (trend). Adult Clinical Trials Reasons for discontinuation of treatment due to adverse reactions in acute adult placebo-controlled trials — In the acute adult placebo-controlled trials, 11.3% (61/541) atomoxetine subjects and 3% (12/405) placebo subjects discontinued for adverse reactions. In the clinical development program, seizures were reported on 0.1% (1/748) of adult patients.

In these clinical trials, no poor metabolizers (0/43) reported seizures compared to 0.1% (1/705) for extensive metabolizers. The most commonly observed adverse reactions in patients treated with atomoxetine (incidence of 5% or greater and at least twice the incidence in placebo patients) were: constipation, dry mouth, nausea, decreased appetite, dizziness, erectile dysfunction, and urinary hesitation (see Table 4). The following reactions did not meet this criterion but were reported by more atomoxetine-treated patients than placebo-treated patients and are possibly related to atomoxetine treatment: peripheral coldness, tachycardia, prostatitis, testicular pain, orgasm abnormal, flatulence, asthenia, feeling cold, muscle spasm, dysgeusia, agitation, restlessness, micturition urgency, pollakiuria, pruritus, urticaria, flushing, tremor, menstruation irregular, rash, and urinary retention.

Male and female sexual dysfunction — Atomoxetine appears to impair sexual function in some patients. Changes in sexual desire, sexual performance, and sexual satisfaction are not well assessed in most clinical trials because they need special attention and because patients and physicians may be reluctant to discuss them. Accordingly, estimates of the incidence of untoward sexual experience and performance cited in product labeling are likely to underestimate the actual incidence.

Table 4 above displays the incidence of sexual side effects reported by at least 2% of adult patients taking atomoxetine in placebo-controlled trials. There are no adequate and well-controlled studies examining sexual dysfunction with atomoxetine treatment. While it is difficult to know the precise risk of sexual dysfunction associated with the use of atomoxetine, physicians should routinely inquire about such possible side effects.

Postmarketing Spontaneous Reports

The following adverse reactions have been identified during post approval use of atomoxetine. Unless otherwise specified, these adverse reactions have occurred in adults and children and adolescents. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Cardiovascular system — QT prolongation, syncope. Peripheral vascular effects — Raynaud’s phenomenon. General disorders and administration site conditions — Lethargy.

Musculoskeletal system - Rhabdomyolysis. Nervous system disorders — Hypoaesthesia; paraesthesia in children and adolescents; sensory disturbances; tics. Psychiatric disorders — Depression and depressed mood; anxiety, libido changes.

Seizures — Seizures have been reported in the postmarketing period. The postmarketing seizure cases include patients with pre-existing seizure disorders and those with identified risk factors for seizures, as well as patients with neither a history of nor identified risk factors for seizures. The exact relationship between atomoxetine and seizures is difficult to evaluate due to uncertainty about the background risk of seizures in ADHD patients.

Skin and subcutaneous tissue disorders — Alopecia, hyperhidrosis. Urogenital system — Male pelvic pain; urinary hesitation in children and adolescents; urinary retention in children and adolescents.

Monoamine Oxidase Inhibitors

With other drugs that affect brain monoamine concentrations, there have been reports of serious, sometimes fatal reactions (including hyperthermia, rigidity, myoclonus, autonomic instability with possible rapid fluctuations of vital signs, and mental status changes that include extreme agitation progressing to delirium and coma) when taken in combination with an MAOI. Some cases presented with features resembling neuroleptic malignant syndrome. Such reactions may occur when these drugs are given concurrently or in close proximity.

Effect of CYP2D6 Inhibitors on Atomoxetine

In extensive metabolizers (EMs), inhibitors of CYP2D6 (e.g., paroxetine, fluoxetine, and quinidine) increase atomoxetine steady-state plasma concentrations to exposures similar to those observed in poor metabolizers (PMs). In EM individuals treated with paroxetine or fluoxetine, the AUC of atomoxetine is approximately 6- to 8-fold and C ss, max is about 3- to 4-fold greater than atomoxetine alone. In vitro studies suggest that coadministration of cytochrome P450 inhibitors to PMs will not increase the plasma concentrations of atomoxetine.

Antihypertensive Drugs and Pressor Agents Because of possible effects on blood pressure, atomoxetine should be used cautiously with antihypertensive drugs and pressor agents (e.g., dopamine, dobutamine) or other drugs that increase blood pressure.

Albuterol Atomoxetine should be administered with caution to patients being treated with systemically-administered (oral or intravenous) albuterol (or other beta 2 agonists) because the action of albuterol on the cardiovascular system can be potentiated resulting in increases in heart rate and blood pressure. Albuterol (600 mcg iv over 2 hours) induced increases in heart rate and blood pressure. These effects were potentiated by atomoxetine (60 mg BID for 5 days) and were most marked after the initial coadministration of albuterol and atomoxetine.

However, these effects on heart rate and blood pressure were not seen in another study after the coadministration with inhaled dose of albuterol (200 to 800 mcg) and atomoxetine (80 mg QD for 5 days) in 21 healthy Asian subjects who were excluded for poor metabolizer status.

Effect of Atomoxetine on P450 Enzymes

Atomoxetine did not cause clinically important inhibition or induction of cytochrome P450 enzymes, including CYP1A2, CYP3A, CYP2D6, and CYP2C9. CYP3A Substrate (e.g., Midazolam) — Coadministration of atomoxetine (60 mg BID for 12 days) with midazolam, a model compound for CYP3A4 metabolized drugs (single dose of 5 mg), resulted in 15% increase in AUC of midazolam. No dose adjustment is recommended for drugs metabolized by CYP3A.

CYP2D6 Substrate (e.g., Desipramine) — Coadministration of atomoxetine (40 or 60 mg BID for 13 days) with desipramine, a model compound for CYP2D6 metabolized drugs (single dose of 50 mg), did not alter the pharmacokinetics of desipramine.

Alcohol Consumption of ethanol with atomoxetine did not change the intoxicating effects of ethanol.

Methylphenidate Coadministration of methylphenidate with atomoxetine did not increase cardiovascular effects beyond those seen with methylphenidate alone.

Drugs Highly Bound to Plasma Protein

In vitro drug-displacement studies were conducted with atomoxetine and other highly-bound drugs at therapeutic concentrations. Atomoxetine did not affect the binding of warfarin, acetylsalicylic acid, phenytoin, or diazepam to human albumin. Similarly, these compounds did not affect the binding of atomoxetine to human albumin.

Drugs that Affect

Gastric pH Drugs that elevate gastric pH (magnesium hydroxide/aluminum hydroxide, omeprazole) had no effect on atomoxetine bioavailability.

Pregnancy: Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ADHD medications, including atomoxetine, during pregnancy. Healthcare providers are encouraged to register patients by calling the National Pregnancy Registry for ADHD Medications at 1-866-961-2388 or visiting https://womensmentalhealth.org/adhd-medications/. Risk Summary Available published studies with atomoxetine use in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes.

Some animal reproduction studies of atomoxetine had adverse developmental outcomes. One of 3 studies in pregnant rabbits dosed during organogenesis resulted in decreased live fetuses and an increase in early resorptions, as well as slight increases in the incidences of atypical origin of carotid artery and absent subclavian artery. These effects were observed at plasma levels (AUC) 3 times and 0.4 times the human plasma levels in extensive and poor metabolizers receiving the maximum recommended human dose (MRHD), respectively.

In rats dosed prior to mating and during organogenesis a decrease in fetal weight (female only) and an increase in the incidence of incomplete ossification of the vertebral arch in fetuses were observed at a dose approximately 5 times the MRHD on a mg/m 2 basis. In one of 2 studies in which rats were dosed prior to mating through the periods of organogenesis and lactation, decreased pup weight and decreased pup survival were observed at doses corresponding to 5 to 6 times the MRHD on a mg/m 2 basis. No adverse fetal effects were seen in pregnant rats dosed during the organogenesis period (see Data).

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is respectively.

Data Animal Data Pregnant rabbits were treated with up to 100 mg/kg/day of atomoxetine by gavage throughout the period of organogenesis. At this dose, in 1 of 3 studies, a decrease in live fetuses and an increase in early resorptions was observed. Slight increases in the incidences of atypical origin of carotid artery and absent subclavian artery were observed.

These findings were observed at doses that caused slight maternal toxicity. The no-effect dose for these findings was 30 mg/kg/day. The 100 mg/kg dose is approximately 23 times the MRHD on a mg/m 2 basis; plasma levels (AUC) of atomoxetine at this dose in rabbits are estimated to be 3.3 times (extensive metabolizers) or 0.4 times (poor metabolizers) those in humans receiving the MRHD.

Rats were treated with up to approximately 50 mg/kg/day of atomoxetine (approximately 6 times the MRHD on a mg/m 2 basis) in the diet from 2 weeks (females) or 10 weeks (males) prior to mating through the periods of organogenesis and lactation. In 1 of 2 studies, decreases in pup weight and pup survival were observed. The decreased pup survival was also seen at 25 mg/kg (but not at 13 mg/kg).

No adverse fetal effects were seen when pregnant rats were treated with up to 150 mg/kg/day (approximately 17 times the MRHD on a mg/m 2 basis) by gavage throughout the period of organogenesis.

Pediatric Use Anyone considering the use of atomoxetine in a child or adolescent must balance the potential risks with the clinical need. The pharmacokinetics of atomoxetine in children and adolescents are similar to those in adults. The safety, efficacy, and pharmacokinetics of atomoxetine in pediatric patients less than 6 years of age have not been evaluated.

A study was conducted in young rats to evaluate the effects of atomoxetine on growth and neurobehavioral and sexual development. Slight delays in onset of vaginal patency (all doses) and preputial separation (10 and 50 mg/kg), slight decreases in epididymal weight and sperm number (10 and 50 mg/kg), and a slight decrease in corpora lutea (50 mg/kg) were seen, but there were no effects on fertility or reproductive performance. A slight delay in onset of incisor eruption was seen at 50 mg/kg.

There were no effects on learning and memory tests. The significance of these findings to humans is unknown.

Hypersensitivity

Atomoxetine capsules are contraindicated in patients known to be hypersensitive to atomoxetine or other constituents of the product.

Monoamine Oxidase Inhibitors (MAOI)

Atomoxetine capsules should not be taken with an MAOI, or within 2 weeks after discontinuing an MAOI. Treatment with an MAOI should not be initiated within 2 weeks after discontinuing atomoxetine capsules. With other drugs that affect brain monoamine concentrations, there have been reports of serious, sometimes fatal reactions (including hyperthermia, rigidity, myoclonus, autonomic instability with possible rapid fluctuations of vital signs, and mental status changes that include extreme agitation progressing to delirium and coma) when taken in combination with an MAOI.

Some cases presented with features resembling neuroleptic malignant syndrome. Such reactions may occur when these drugs are given concurrently or in close proximity.

Narrow Angle Glaucoma

In clinical trials, atomoxetine capsules use was associated with an increased risk of mydriasis and therefore its use is not recommended in patients with narrow angle glaucoma.

Pheochromocytoma

Serious reactions, including elevated blood pressure and tachyarrhythmia, have been reported in patients with pheochromocytoma or a history of pheochromocytoma who received atomoxetine capsules. Therefore, atomoxetine capsules should not be taken by patients with pheochromocytoma or a history of pheochromocytoma.

Severe Cardiovascular Disorders

Atomoxetine capsules should not be used in patients with severe cardiac or vascular disorders whose condition would be expected to deteriorate if they experience increases in blood pressure or heart rate that could be clinically important (for example, 15 to 20 mm Hg in blood pressure or 20 beats per minute in heart rate).

Human Experience There is limited clinical trial experience with atomoxetine overdose. During postmarketing, there have been fatalities reported involving a mixed ingestion overdose of atomoxetine and at least one other drug. There have been no reports of death involving overdose of atomoxetine alone, including intentional overdoses at amounts up to 1400 mg.

In some cases of overdose involving atomoxetine, seizures have been reported. The most commonly reported symptoms accompanying acute and chronic overdoses of atomoxetine were gastrointestinal symptoms, somnolence, dizziness, tremor, and abnormal behavior. Hyperactivity and agitation have also been reported.

Signs and symptoms consistent with mild to moderate sympathetic nervous system activation (e.g., tachycardia, blood pressure increased, mydriasis, dry mouth) have also been observed. Most events were mild to moderate. Less commonly, there have been reports of QT prolongation and mental changes, including disorientation and hallucinations.

Management of Overdose Consult with a Certified Poison Control Center for up to date guidance and advice. Because atomoxetine is highly protein-bound, dialysis is not likely to be useful in the treatment of overdose.