Transporters fpr norepinephrine (NE), serotonin (5-HT) and dopamine (DA); SNRI/selective noradrenaline reuptake inhibitor

The human heart sodium channel (hNav1.5) is interacting with tomoxetine (1-100 µM; 0.5-20 sec; tsA201 cells) in a state- and dose-dependent way [2].

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Atomoxetine Hydrochloride is the hydrochloride salt of atomoxetine, a phenoxy-3-propylamine derivative and selective non-stimulant, norepinephrine reuptake inhibitor with cognitive-enhancing activity. Although its precise mechanism of action is unknown, atomoxetine appears to selectively inhibit the pre-synaptic norepinephrine transporter, resulting in inhibition of the presynaptic reabsorption of norepinephrine and prolongation of norepinephrine activity in the synaptic cleft. The effect on cognitive brain function may result in improved attention and decreased impulsivity and activity levels.

Tomoxetine (0.3-3 mg/kg; i.p.; 0-4 hours; male Sprague-Dawley rats) increases extracellular norepinephrine and dopamine 3-fold and increases intracellular Expression of Fos[1]. Tomoxetine (0.1-5 mg/kg; intraperitoneal injection and oral administration; for 14 days; spontaneously hypertensive rats) can improve ADHD-related behaviors in rats [3].

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Atomoxetine (ATX) is a commonly used non-stimulant treatment for Attention deficit hyperactivity disorder (ADHD). It primarily acts to increase noradrenalin levels; however, at higher doses it can increase dopamine levels. To date there has been no investigations into the effects of orally-administered ATX in the most commonly used model of ADHD, the spontaneously hypertensive rat (SHR). The aim of this study was to describe the effects of doses thought to be selective (0.15 mg/kg) and non-selective (0.3 mg/kg) for noradrenalin on behavioural measures in the SHR. Firstly, we examined the effects of acute and chronic ATX on locomotor activity including sensitisation and cross-sensitisation to amphetamine. Secondly, we measured drug effects on impulsivity using a T-maze delay discounting paradigm. We found no effect of ATX on locomotor activity and no evidence for sensitisation or cross-sensitisation. Furthermore, there were no differences in T-maze performance, indicating no effects on impulsivity at these doses. The absence of behavioural sensitisation supports previous claims of superior safety relative to psychostimulants for the doses administered. There was also no effect on impulsivity; however, we suggest that was confounded by stress specific to SHRs. Implications for future studies, behavioural assessment of SHRs and their use as a model of ADHD are discussed[1].

Atomoxetine, a neuroactive drug, is approved for the treatment of attention-deficit/hyperactivity disorder (ADHD). It is primarily known as a high affinity blocker of the noradrenaline transporter, whereby its application leads to an increased level of the corresponding neurotransmitter in different brain regions. However, the concentrations used to obtain clinical effects are much higher than those which are required to block the transporter system. Thus, off-target effects are likely to occur. In this way, we previously identified atomoxetine as blocker of NMDA receptors. As many psychotropic drugs give rise to sudden death of cardiac origin, we now tested the hypothesis whether atomoxetine also interacts with voltage-gated sodium channels of heart muscle type in clinically relevant concentrations. Electrophysiological experiments were performed by means of the patch-clamp technique at human heart muscle sodium channels (hNav1.5) heterogeneously expressed in human embryonic kidney cells. Atomoxetine inhibited sodium channels in a state- and use-dependent manner. Atomoxetine had only a weak affinity for the resting state of the hNav1.5 (Kr: ∼ 120 µM). The efficacy of atomoxetine strongly increased with membrane depolarization, indicating that the inactivated state is an important target. A hallmark of this drug was its slow interaction. By use of different experimental settings, we concluded that the interaction occurs with the slow inactivated state as well as by slow kinetics with the fast-inactivated state. Half-maximal effective concentrations (2-3 µM) were well within the concentration range found in plasma of treated patients. Atomoxetine also interacted with the open channel. However, the interaction was not fast enough to accelerate the time constant of fast inactivation. Nevertheless, when using the inactivation-deficient hNav1.5_I408W_L409C_A410W mutant, we found that the persistent late current was blocked half maximal at about 3 µM atomoxetine. The interaction most probably occurred via the local anesthetic binding site. Atomoxetine inhibited sodium channels at a similar concentration as it is used for the treatment of ADHD. Due to its slow interaction and by inhibiting the late current, it potentially exerts antiarrhythmic properties[2].

Animal/Disease Models: Male SD (SD (Sprague-Dawley)) rat [1]
Doses: 0.3, 1 and 3 mg/kg
Route of Administration: intraperitoneal (ip) injection; 4 hrs (hrs (hours))
Experimental Results: The number of cells expressing Fos-like immunoreactivity increased 3.7-fold in the PFC, extracellular Norepinephrine and dopamine increase 3-fold.

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Animal/Disease Models: Spontaneously hypertensive rat (SHR) [3]
Doses: 0.1, 0.3, 1.25 and 5.0 mg/kg
Route of Administration: intraperitoneal (ip) injection and oral administration; continued for 14 days
Experimental Results: No effect on measurements of locomotor activity.

Absorption, Distribution and Excretion
The pharmacokinetic profile of atomoxetine is highly dependent on cytochrome P450 2D6 genetic polymorphisms of the individual. A large fraction of the population (up to 10% of Caucasians and 2% of people of African descent and 1% of Asians) are poor metabolizers (PMs) of CYP2D6 metabolized drugs. These individuals have reduced activity in this pathway resulting in 10-fold higher AUCs, 5-fold higher peak plasma concentrations, and slower elimination (plasma half-life of 21.6 hours) of atomoxetine compared with people with normal CYP2D6 activity. Atomoxetine is rapidly absorbed after oral administration, with absolute bioavailability of about 63% in extensive metabolizers (EMs) and 94% in poor metabolizers (PMs). Mean maximal plasma concentrations (Cmax) are reached approximately 1 to 2 hours after dosing with a maximal concentration of 350 ng/ml with an AUC of 2 mcg.h/ml.
Atomoxetine is excreted primarily as 4-hydroxyatomoxetine-O-glucuronide, mainly in the urine (greater than 80% of the dose) and to a lesser extent in the feces (less than 17% of the dose). Only a small fraction (less than 3%) of the atomoxetine dose is excreted as unchanged atomoxetine, indicating extensive biotransformation.
The reported volume of distribution of oral atomoxetine was 1.6-2.6 L/kg. The steady-state volume of distribution of intravenous atomoxetine was approximately 0.85 L/kg.
The clearance rate of atomoxetine depends the CYP2D6 genetic polymorphisms of the individual and can range of 0.27-0.67 L.h/kg.
Steady-state volume of distribution (intravenous administration): 8.5 L/kg. Atomexetine distributes primarily into total body water; volume of distribution is similar across patient weight range after normalizing for body weight.
Atomoxetine is rapidly absorbed after oral administration, with absolute bioavailability of about 63% in extensive metabolizers and 94% in poor metabolizers. Maximal plasma concentrations (Cmax) are reached approximately 1 to 2 hours after dosing.
/MILK/ Atomoxetine and/or its metabolites are distributed into milk in rats; it is not known whether the drug is distributed into milk in humans.
... Atomoxetine has high aqueous solubility and biological membrane permeability that facilitates its rapid and complete absorption after oral administration. Absolute oral bioavailability ranges from 63 to 94%, which is governed by the extent of its first-pass metabolism. Three oxidative metabolic pathways are involved in the systemic clearance of atomoxetine: aromatic ring-hydroxylation, benzylic hydroxylation and N-demethylation. Aromatic ring-hydroxylation results in the formation of the primary oxidative metabolite of atomoxetine, 4-hydroxyatomoxetine, which is subsequently glucuronidated and excreted in urine. The formation of 4-hydroxyatomoxetine is primarily mediated by the polymorphically expressed enzyme cytochrome P450 (CYP) 2D6. This results in two distinct populations of individuals: those exhibiting active metabolic capabilities (CYP2D6 extensive metabolizers) and those exhibiting poor metabolic capabilities (CYP2D6 poor metabolizers) for atomoxetine. The oral bioavailability and clearance of atomoxetine are influenced by the activity of CYP2D6; nonetheless, plasma pharmacokinetic parameters are predictable in extensive and poor metabolizer patients. After single oral dose, atomoxetine reaches maximum plasma concentration within about 1-2 hours of administration. In extensive metabolizers, atomoxetine has a plasma half-life of 5.2 hours, while in poor metabolizers, atomoxetine has a plasma half-life of 21.6 hours. The systemic plasma clearance of atomoxetine is 0.35 and 0.03 L/h/kg in extensive and poor metabolizers, respectively. Correspondingly, the average steady-state plasma concentrations are approximately 10-fold higher in poor metabolizers compared with extensive metabolizers. Upon multiple dosing there is plasma accumulation of atomoxetine in poor metabolizers, but very little accumulation in extensive metabolizers. The volume of distribution is 0.85 L/kg, indicating that atomoxetine is distributed in total body water in both extensive and poor metabolizers. Atomoxetine is highly bound to plasma albumin (approximately 99% bound in plasma). Although steady-state concentrations of atomoxetine in poor metabolizers are higher than those in extensive metabolizers following administration of the same mg/kg/day dosage, the frequency and severity of adverse events are similar regardless of CYP2D6 phenotype.Atomoxetine administration does not inhibit or induce the clearance of other drugs metabolized by CYP enzymes. In extensive metabolizers, potent and selective CYP2D6 inhibitors reduce atomoxetine clearance; however, administration of CYP inhibitors to poor metabolizers has no effect on the steady-state plasma concentrations of atomoxetine.
For more Absorption, Distribution and Excretion (Complete) data for ATOMOXETINE (8 total), please visit the HSDB record page.

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Metabolism / Metabolites
Atomoxetine undergoes biotransformation primarily through the cytochrome P450 2D6 (CYP2D6) enzymatic pathway. People with reduced activity in the CYP2D6 pathway (also known as poor metabolizers or PMs) have higher plasma concentrations of atomoxetine compared with people with normal activity (also known as extensive metabolizers, or EMs). For PMs, the AUC of atomoxetine at steady-state is approximately 10-fold higher and Cmax is about 5-fold greater than for EMs. The major oxidative metabolite formed regardless of CYP2D6 status is 4-hydroxy-atomoxetine, which is rapidly glucuronidated. 4-Hydroxyatomoxetine is equipotent to atomoxetine as an inhibitor of the norepinephrine transporter, but circulates in plasma at much lower concentrations (1% of atomoxetine concentration in EMs and 0.1% of atomoxetine concentration in PMs). In individuals that lack CYP2D6 activity, 4-hydroxyatomoxetine is still the primary metabolite, but is formed by several other cytochrome P450 enzymes and at a slower rate. Another minor metabolite, N-Desmethyl-atomoxetine is formed by CYP2C19 and other cytochrome P450 enzymes, but has much less pharmacological activity than atomoxetine and lower plasma concentrations (5% of atomoxetine concentration in EMs and 45% of atomoxetine concentration in PMs).
Atomoxetine is metabolized primarily through the CYP2D6 enzymatic pathway. People with reduced activity in this pathway (PMs) have higher plasma concentrations of atomoxetine compared with people with normal activity (EMs). For PMs, AUC of atomoxetine is approximately 10-fold and Css, max is about 5-fold greater than EMs. Laboratory tests are available to identify CYP2D6 PMs.
The major oxidative metabolite formed, regardless of CYP2D6 status, is 4-hydroxyatomoxetine, which is glucuronidated. 4-Hydroxyatomoxetine is equipotent to atomoxetine as an inhibitor of the norepinephrine transporter but circulates in plasma at much lower concentrations (1% of atomoxetine concentration in extensive metabolizers (EMs) and 0.1% of atomoxetine concentration in PMs). 4-Hydroxyatomoxetine is primarily formed by CYP2D6, but in PMs, 4-hydroxyatomoxetine is formed at a slower rate by several other cytochrome P450 enzymes. N-Desmethylatomoxetine is formed by CYP2C19 and other cytochrome P450 enzymes, but has substantially less pharmacological activity compared with atomoxetine and circulates in plasma at lower concentrations (5% of atomoxetine concentration in EMs and 45% of atomoxetine concentration in poor metabolizers (PMs)).
The role of the polymorphic cytochrome p450 2D6 (CYP2D6) in the pharmacokinetics of atomoxetine hydrochloride [(-)-N-methyl-gamma-(2-methylphenoxy)benzenepropanamine hydrochloride; LY139603] has been documented following both single and multiple doses of the drug. In this study, the influence of the CYP2D6 polymorphism on the overall disposition and metabolism of a 20-mg dose of (14)C-atomoxetine was evaluated in CYP2D6 extensive metabolizer (EM; n = 4) and poor metabolizer (PM; n = 3) subjects under steady-state conditions. Atomoxetine was well absorbed from the gastrointestinal tract and cleared primarily by metabolism with the preponderance of radioactivity being excreted into the urine. In EM subjects, the majority of the radioactive dose was excreted within 24 hr, whereas in PM subjects the majority of the dose was excreted by 72 hr. The biotransformation of atomoxetine was similar in all subjects undergoing aromatic ring hydroxylation, benzylic oxidation, and N-demethylation with no CYP2D6 phenotype-specific metabolites. The primary oxidative metabolite of atomoxetine was 4-hydroxyatomoxetine, which was subsequently conjugated forming 4-hydroxyatomoxetine-O-glucuronide. Due to the absence of CYP2D6 activity, the systemic exposure to radioactivity was prolonged in PM subjects (t(1/2) = 62 hr) compared with EM subjects (t(1/2) = 18 hr). In EM subjects, atomoxetine (t(1/2) = 5 hr) and 4-hydroxyatomoxetine-O-glucuronide (t(1/2) = 7 hr) were the principal circulating species, whereas atomoxetine (t(1/2) = 20 hr) and N-desmethylatomoxetine (t(1/2) = 33 hr) were the principal circulating species in PM subjects. Although differences were observed in the excretion and relative amounts of metabolites formed, the primary difference observed between EM and PM subjects was the rate at which atomoxetine was biotransformed to 4-hydroxyatomoxetine.
Atomoxetine is excreted primarily as 4-hydroxyatomoxetine-O-glucuronide, mainly in the urine (greater than 80% of the dose) and to a lesser extent in the feces (less than 17% of the dose). Only a small fraction of the Strattera dose is excreted as unchanged atomoxetine (less than 3% of the dose), indicating extensive biotransformation.
For more Metabolism/Metabolites (Complete) data for ATOMOXETINE (8 total), please visit the HSDB record page.
Atomoxetine is primarily metabolized by the CYP2D6 pathway to 4-hydroxyatomoxetine. 4-Hydroxyatomoxetine is equipotent to atomoxetine as an inhibitor of the norepinephrine transporter but circulates in plasma at much lower concentrations (1% of atomoxetine concentration in EMs and 0.1% of atomoxetine concentration in PMs).
Half Life: 5 hours

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Biological Half-Life
The reported half-life depends on the CYP2D6 genetic polymorphisms of the individual and can range from 3 to 5.6 hours.
The plasma elimination half life in normal (extensive) metabolizers is about 5 hours. In person who are poor metabolizers (7% of whites and 2% of blacks), the drug plasma levels are much higher and the plasma elimination half life is 24 hours.
Mean apparent plasma clearance of atomoxetine after oral administration in adult extensive metabolizers (EMs) is 0.35 L/hr/kg and the mean half-life is 5.2 hours. Following oral administration of atomoxetine to poor metabolizers (PMs), mean apparent plasma clearance is 0.03 L/hr/kg and mean half-life is 21.6 hours. For PMs, AUC of atomoxetine is approximately 10-fold and Css, max is about 5-fold greater than EMs. The elimination half-life of 4-hydroxyatomoxetine is similar to that of N-desmethylatomoxetine (6 to 8 hours) in EM subjects, while the half-life of N-desmethylatomoxetine is much longer in PM subjects (34 to 40 hours).
... In extensive metabolizers, atomoxetine has a plasma half-life of 5.2 hours, while in poor metabolizers, atomoxetine has a plasma half-life of 21.6 hours. ...
... Twenty-one cytochrome P450 2D6 extensive metabolizer patients participated in these single-dose and steady-state pharmacokinetic evaluations. Atomoxetine was rapidly absorbed, with peak plasma concentrations occurring 1 to 2 hours after dosing. Half-life averaged 3.12 and 3.28 hours after a single dose and at steady state, respectively. ...

Toxicity Summary
IDENTIFICATION AND USE: Atomoxetine, as Strattera, is indicated for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD). HUMAN EXPOSURE AND TOXICITY: Atomoxetine increased the risk of suicidal ideation in short-term studies in children or adolescents with ADHD. Symptoms accompanying acute and chronic overdoses of atomoxetine include gastrointestinal symptoms, somnolence, dizziness, tremor, abnormal behavior, hyperactivity, agitation, and signs and symptoms consistent with mild to moderate sympathetic nervous system activation (e.g., tachycardia, blood pressure increased, mydriasis, dry mouth). Less commonly, there have been reports of QT prolongation and mental changes, including disorientation and hallucinations. Atomoxetine may cause clinically significant hepatotoxicity either by metabolic idiosyncrasy or by inducing autoimmune hepatitis. There have been fatalities reported involving a mixed ingestion overdose of Strattera and at least one other drug. Sudden deaths, stroke, and myocardial infarction have been reported in both children and adults with structural cardiac abnormalities or other serious heart problems. ANIMAL STUDIES: The median lethal oral dose of atomoxetine hydrochloride in animals was estimated to be 25 mg/kg for cats, >37.5 mg/kg for dogs, and 0.190 mg/kg in rats and mice. Premonitory signs of toxicity following single oral doses of atomoxetine in animals included mydriasis and reduced pupillary light reflex, mucoid stools, salivation, vomiting, ataxia, tremors, myoclonic jerking, and convulsions. Chronic toxicity studies of up to 1 year were conducted in adult rats and dogs. There was no major target organ toxicity observed in dogs given oral doses up to 16 mg/kg/day or in rats given atomoxetine in the diet at time-weighted average doses up to 47 mg/kg/day. These doses are 4-5 times the maximum recommended daily oral dose in adults. Mild hepatic effects, characterized by mottling and pallor of the liver, increased relative liver weights, hepatocellular vacuolation, and slightly increased serum ALT values, occurred in male rats given time weighted average doses >/= 14 mg/kg/day. No hepatic effects were observed in dogs. Clinical signs of mydriasis, reduced pupillary light reflex, emesis, and tremors were observed in dogs, and these effects were minimal in adult dogs given >/= 8 mg/kg/day. No evidence of drug-associated teratogenicity or retarded fetal development was produced in rabbits or rats administered atomoxetine hydrochloride throughout organogenesis at oral doses up to 100 mg/kg/day and 150 mg/kg/day (13 times the maximum recommended daily oral dose in adults). In a rat fertility study, decreased pup weight and survival was observed, predominantly during the first week postpartum following maternal dietary atomoxetine timeweighted average doses of 23 mg/kg/day or higher. Atomoxetine hydrochloride was negative in a battery of genotoxicity studies that included a reverse point mutation assay (Ames Test), an in vitro mouse lymphoma assay, a chromosomal aberration test in Chinese hamster ovary cells, an unscheduled DNA synthesis test in rat hepatocytes, and an in vivo micronucleus test in mice. However, there was a slight increase in the percentage of Chinese hamster ovary cells with diplochromosomes, suggesting endoreduplication (numerical aberration). Atomoxetine hydrochloride was not carcinogenic in rats and mice when given in the diet for 2 years at time-weighted average doses up to 47 and 458 mg/kg/day, respectively.
The precise mechanism by which atomoxetine produces its therapeutic effects in Attention-Deficit/Hyperactivity Disorder (ADHD) is unknown, but is thought to be related to selective inhibition of the pre-synaptic norepinephrine transporter, as determined through in-vitro studies. Atomoxetine appears to have minimal affinity for other noradrenergic receptors or for other neurotransmitter transporters or receptors.

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Interactions
Strattera should be administered with caution to patients being treated with systemically-administered (oral or intravenous) albuterol (or other beta2 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 (200-800 ug) and atomoxetine (80 mg QD for 5 days) in 21 healthy Asian subjects who were excluded for poor metabolizer status.
The manufacturer states that atomoxetine is contraindicated in patients currently receiving or having recently received (i.e., within 2 weeks) monoamine oxidase (MAO) inhibitor therapy. In addition, at least 2 weeks should elapse after discontinuing atomoxetine before initiating MAO inhibitor therapy. Severe, potentially 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) have been reported in patients receiving other drugs that affect brain monoamine concentrations concomitantly with MAO inhibitor therapy.
Potential pharmacokinetic interaction (decreased metabolism of atomoxetine) when atomoxetine is used concomitantly with drugs that inhibit the activity of the cytochrome P-450 2D6 (CYP2D6) isoenzyme. Inhibitors of CYP2D6 may increase plasma concentrations of atomoxetine in patients with the extensive-metabolizer phenotype to such an extent that plasma concentrations of the drug are similar to those achieved in poor metabolizers. When atomoxetine is used concomitantly with potent CYP2D6 inhibitors (e.g., paroxetine, fluoxetine, quinidine), or in patients with poor-metabolizer phenotypes of the CYP2D6 isoenzyme, the manufacturer states that dosage adjustment of atomoxetine should be considered. However, in vitro studies suggest that concomitant use of atomoxetine with CYP2D6 inhibitors will not increase plasma concentrations of atomoxetine in patients with the poor-metabolizer phenotype.
Potential pharmacologic interaction (increased hypertensive effects) with concomitant use of pressor agents (e.g., dopamine, dobutamine) and atomoxetine. Use with caution.
For more Interactions (Complete) data for ATOMOXETINE (6 total), please visit the HSDB record page.

[1]. Effects of atomoxetine on locomotor activity and impulsivity in the spontaneously hypertensive rat. Behav Brain Res. 2013 Apr 15;243:28-37.

[2]. Block of Voltage-Gated Sodium Channels by Atomoxetine in a State- and Use-dependent Manner. Front Pharmacol. 2021 Feb 25;12:622489.

[3]. Atomoxetine increases extracellular levels of norepinephrine and dopamine in prefrontal cortex of rat: a potential mechanism for efficacy in attention deficit/hyperactivity disorder. Neuropsychopharmacology. 2002 Nov;27(5):699-711.

Therapeutic Uses
Adrenergic Uptake Inhibitors
/CLINICAL TRIALS/ ClinicalTrials.gov is a registry and results database of publicly and privately supported clinical studies of human participants conducted around the world. The Web site is maintained by the National Library of Medicine (NLM) and the National Institutes of Health (NIH). Each ClinicalTrials.gov record presents summary information about a study protocol and includes the following: Disease or condition; Intervention (for example, the medical product, behavior, or procedure being studied); Title, description, and design of the study; Requirements for participation (eligibility criteria); Locations where the study is being conducted; Contact information for the study locations; and Links to relevant information on other health Web sites, such as NLM's MedlinePlus for patient health information and PubMed for citations and abstracts for scholarly articles in the field of medicine. Atomoxetine is included in the database.
Strattera is indicated for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD). /Included in US product labeling/
/EXPL THER/ /The purpose of this study was/ to observe the efficacy and safety of atomoxetine hydrochloride in children with narcolepsy. Totally 66 patients with narcolepsy who were conformed international classification of sleep disturbances (ICSD-2) diagnostic criteria treated with atomoxetine hydrochloride seen from November 2010 to December 2014 were enrolled into this study, 42 of them were male and 24 female, mean age of onset was 7.5 years (3.75-13.00 years), mean duration before diagnosis was 1.75 years (0.25-5.00 years). Complete blood count, liver and kidney function, multiple sleep latency test (MSLT), polysomnography (PGS), neuroimaging and electroencephalography (EEG) were performed for each patient. For some of the children HLA-DR2 gene and serum markers of infection were tested. The 66 cases were followed up from 2 to 49 months (average 18 months) to observe the clinical efficacy and adverse reactions. In 62 cases excessive daytime sleepiness was improved, in 11 cases (16.7%) it was controlled (16.7%), in 29 cases (43.9%) the treatment was obviously effective and in 22 (33.3%) it was effective; cataplexy occurred in 54 cases, in 18 (33.3%) it was controlled, in 19 (35.2%) the treatment was obviously effective and in 10 (18.5%) effective; night sleep disorders existed in 55 cases, in 47 cases it was improved, in 14 (25.5%) it was controlled, in 20 (36.4%) the treatment was obviously effective and in 13 (23.6%) effective; hypnagogic or hypnopompic hallucination was present in 13 cases, in only 4 these symptoms were controlled. Sleep paralysis existed in 4 cases, it was controlled in only 1 case. In 18 cases attention and learning efficiency improved.Anorexia occurred in 18 cases, mood disorder in 5 cases, depression in 2 cases, nocturia, muscle tremors, involuntary tongue movement each occurred in 1 case. P-R interval prolongation and atrial premature contraction were found in 1 case. Atomoxetine hydrochloride showed good effects in patients with narcolepsy on excessive daytime sleepiness, cataplexy and night sleep disorders, the effects on hallucinations and sleep paralysis were not significant. Adverse reactions were slight, anorexia and mood disorder were common. As a non-central nervous system stimulant, atomoxetine hydrochloride does not induce drug dependence and has no prescription limits; it has good tolerability, safety and effectiveness, it can be a good alternative in treatment of children with narcolepsy.
For more Therapeutic Uses (Complete) data for ATOMOXETINE (6 total), please visit the HSDB record page.

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Drug Warnings
/BOXED WARNING/ WARNING: SUICIDAL IDEATION IN CHILDREN AND ADOLESCENTS. Strattera (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 Strattera in a child or adolescent must balance this risk with the clinical need. Co-morbidities occurring with ADHD may be associated with an increase in the risk of suicidal ideation and/or behavior. Patients who are started on therapy should be monitored closely for suicidality (suicidal thinking and behavior), clinical worsening, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. Strattera is approved for ADHD in pediatric and adult patients. Strattera is not approved for major depressive disorder. Pooled analyses of short-term (6 to 18 weeks) placebo-controlled trials of Strattera in children and adolescents (a total of 12 trials involving over 2200 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 Strattera compared to placebo. The average risk of suicidal ideation in patients receiving Strattera was 0.4% (5/1357 patients), compared to none in placebo-treated patients (851 patients). No suicides occurred in these trials.
Postmarketing reports indicate that Strattera can cause severe liver injury. Although no evidence of liver injury was detected in clinical trials of about 6000 patients, there have been rare cases of clinically significant liver injury that were considered probably or possibly related to Strattera use in postmarketing experience. Rare cases of liver failure have also been reported, including a case that resulted in a liver transplant. Because of probable underreporting, it is impossible to provide an accurate estimate of the true incidence of these reactions. Reported cases of liver injury occurred within 120 days of initiation of atomoxetine in the majority of cases and some patients presented with markedly elevated liver enzymes [>20 X upper limit of normal (ULN)], and jaundice with significantly elevated bilirubin levels (>2 X ULN), followed by recovery upon atomoxetine discontinuation. In one patient, liver injury, manifested by elevated hepatic enzymes up to 40 X ULN and jaundice with bilirubin up to 12 X ULN, recurred upon rechallenge, and was followed by recovery upon drug discontinuation, providing evidence that Strattera likely caused the liver injury. Such reactions may occur several months after therapy is started, but laboratory abnormalities may continue to worsen for several weeks after drug is stopped. The patient described above recovered from his liver injury, and did not require a liver transplant.
Strattera should be discontinued in patients with jaundice or laboratory evidence of liver injury, and should not be restarted. Laboratory testing to determine liver enzyme levels should be done upon the first symptom or sign of liver dysfunction (e.g., pruritus, dark urine, jaundice, right upper quadrant tenderness, or unexplained "flu like" symptoms).
The manufacturer states that atomoxetine is contraindicated in patients currently receiving or having recently received (i.e., within 2 weeks) monoamine oxidase (MAO) inhibitor therapy. In addition, at least 2 weeks should elapse after discontinuing atomoxetine before initiating MAO inhibitor therapy. Severe, potentially 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) have been reported in patients receiving other drugs that affect brain monoamine concentrations concomitantly with MAO inhibitor therapy.
For more Drug Warnings (Complete) data for ATOMOXETINE (26 total), please visit the HSDB record page.

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Pharmacodynamics
Atomoxetine is a selective norepinephrine (NE) reuptake inhibitor used for the treatment of attention deficit hyperactivity disorder (ADHD). Atomoxetine has been shown to specifically increase norepinephrine and dopamine within the prefrontal cortex, which results in improved ADHD symptoms. Due to atomoxetine's noradrenergic activity, it also has effects on the cardiovascular system such as increased blood pressure and tachycardia. Sudden deaths, stroke, and myocardial infarction have been reported in patients taking atomoxetine at usual doses for ADHD. Atomoxetine should be used with caution in patients whose underlying medical conditions could be worsened by increases in blood pressure or heart rate such as certain patients with hypertension, tachycardia, or cardiovascular or cerebrovascular disease. It should not be used in patients with severe cardiac or vascular disorders whose condition would be expected to deteriorate if they experienced clinically important increases in blood pressure or heart rate. Although the role of atomoxetine in these cases is unknown, consideration should be given to not treating patients with clinically significant cardiac abnormalities. Patients who develop symptoms such as exertional chest pain, unexplained syncope, or other symptoms suggestive of cardiac disease during atomoxetine treatment should undergo a prompt cardiac evaluation. In general, particular care should be taken in treating ADHD in patients with comorbid bipolar disorder because of concern for possible induction of a mixed/manic episode in patients at risk for bipolar disorder. Treatment emergent psychotic or manic symptoms, e.g., hallucinations, delusional thinking, or mania in children and adolescents without a prior history of psychotic illness or mania can be caused by atomoxetine at usual doses. If such symptoms occur, consideration should be given to a possible causal role of atomoxetine, and discontinuation of treatment should be considered. Atomoxetine capsules increased the risk of suicidal ideation in short-term studies in children and adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD). All pediatric patients being treated with atomoxetine should be monitored appropriately and observed closely for clinical worsening, suicidality, and 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. Postmarketing reports indicate that atomoxetine can cause severe liver injury. Although no evidence of liver injury was detected in clinical trials of about 6000 patients, there have been rare cases of clinically significant liver injury that were considered probably or possibly related to atomoxetine use in postmarketing experience. Rare cases of liver failure have also been reported, including a case that resulted in a liver transplant. Atomoxetine should be discontinued in patients with jaundice or laboratory evidence of liver injury, and should not be restarted. Laboratory testing to determine liver enzyme levels should be done upon the first symptom or sign of liver dysfunction (e.g., pruritus, dark urine, jaundice, right upper quadrant tenderness, or unexplained “flu like” symptoms).

C17H21NO

255.354744672775

255.162

C, 79.96; H, 8.29; N, 5.49; O, 6.27

83015-26-3

Atomoxetine hydrochloride;82248-59-7;(Rac)-Atomoxetine-d7 hydrochloride;Atomoxetine-d3 hydrochloride;1217776-38-9

54841

Typically exists as solid at room temperature

1.0±0.1 g/cm3

389.0±37.0 °C at 760 mmHg

161-165 ºC

164.1±16.0 °C

0.0±0.9 mmHg at 25°C

1.552

3.28

1

2

6

19

237

1

[C@H](C1C=CC=CC=1)(CCNC)OC1C=CC=CC=1C

VHGCDTVCOLNTBX-QGZVFWFLSA-N

InChI=1S/C17H21NO/c1-14-8-6-7-11-16(14)19-17(12-13-18-2)15-9-4-3-5-10-15/h3-11,17-18H,12-13H2,1-2H3/t17-/m1/s1

(3R)-N-methyl-3-(2-methylphenoxy)-3-phenylpropan-1-amine

Atomoxetine; 83015-26-3; Tomoxetine; (-)-Tomoxetine; Tomoxetina; Tomoxetinum; Strattera; Tomoxetinum [Latin];

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)