Atomoxetine Stats & Data
CNCCC(Oc1ccccc1C)c1ccccc1VHGCDTVCOLNTBX-QGZVFWFLSA-NPharmacology
DrugBankDescription
Atomoxetine is a selective norepinephrine (NE) reuptake inhibitor used for the treatment of attention deficit hyperactivity disorder (ADHD). Also known as the marketed product Strattera, atomoxetine is used with other treatment modalities (psychological, educational, cognitive behaviour therapy, etc) to improve developmentally inappropriate symptoms associated with ADHD including distractibility, short attention span, hyperactivity, emotional lability, and impulsivity. Although the underlying pathophysiology that causes ADHD remains unclear, evidence suggests that dysregulation in noradrenergic and dopaminergic pathways plays a critical role in suboptimal executive functioning within prefrontal regions of the brain, which are involved in attention and memory. Atomoxetine has been shown to specifically increase NA and DA within the prefrontal cortex, but not in the nucleus accumbens (NA) or striatum. This is beneficial in the treatment of ADHD as DA activation in the subcortical NA and striatum is associated with many stimulant-associated side effects and an increase in abuse potential, which is a limiting factor associated with the use of stimulant medications such as DB00422, DB01576, and DB01255. Use of non-stimulant medications such as atomoxetine is therefore thought to offer a clinical advantage over the use of traditional medications for the management of ADHD.
Mechanism of Action
Atomoxetine is known to be a potent and selective inhibitor of the norepinephrine transporter (NET), which prevents cellular reuptake of norepinephrine throughout the brain, which is thought to improve the symptoms of ADHD. More recently, positron emission tomography (PET) imaging studies in rhesus monkeys have shown that atomoxetine also binds to the serotonin transporter (SERT), and blocks the N-methyl-d-aspartate (NMDA) receptor, indicating a role for the glutamatergic system in the pathophysiology of ADHD.
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.
Metabolism
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).
Absorption
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.
Toxicity
There is limited clinical trial experience with atomoxetine overdose. During postmarketing, there have been fatalities reported involving a mixed ingestion overdose of atomoxetine capsules and at least one other drug. There have been no reports of death involving overdose of atomoxetine capsules 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 capsules 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. If symptoms of overdose are suspected, a Certified Poison Control Center should be consulted 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.
Indication
Atomoxetine is indicated for the treatment of attention deficit hyperactivity disorder (ADHD) in children and adults.
Half-life
The reported half-life depends on the CYP2D6 genetic polymorphisms of the individual and can range from 3 to 5.6 hours.
Protein Binding
At therapeutic concentrations, 98.7% of plasma atomoxetine is bound to protein, with 97.5% of that being bound to albumin, followed by alpha-1-acid glycoprotein and immunoglobulin G.
Elimination
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.
Volume of Distribution
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.
Clearance
The clearance rate of atomoxetine depends the CYP2D6 genetic polymorphisms of the individual and can range of 0.27-0.67 L.h/kg.
Effect Profile
Curated + 35 ReportsStrong stimulation and anxiety/jitters with moderate euphoria and focus
Tolerance & Pharmacokinetics
drugs.wikiTolerance Decay
Experience Report Analysis
ErowidDemographics
Gender Distribution
Age Distribution
Reports Over Time
Effect Analysis
ErowidEffects aggregated from 35 experience reports (35 Erowid)
Effect Sentiment Distribution
Confidence Distribution
Positive Effects 8
Adverse Effects 6
Dose-Response Correlation
How effect frequency changes across dose levels
View data table
| Effect | Strong (n=12) |
|---|---|
| Anxiety | 58.3% |
| Focus Enhancement | 50.0% |
| Sedation | 50.0% |
| Stimulation | 50.0% |
| Nausea | 33.3% |
| Headache | 16.7% |
| Auditory Effects | 16.7% |
| Color Enhancement | 16.7% |
| Euphoria | 16.7% |
| Hospital | 16.7% |
| Sweating | 16.7% |
| Empathy | 16.7% |
| Dissociation | 16.7% |
| Body High | 16.7% |
Dose–Effect Mapping
Experience ReportsHow reported effects shift across dose tiers, based on 35 experience reports.
Limited tier coverage — most reports fall within the Strong range. Effects at other dose levels may not be represented.
| Effect | Strong (n=12) | |
|---|---|---|
| anxiety | ||
| focus enhancement | ||
| sedation | ||
| stimulation | ||
| nausea | ||
| headache | ||
| auditory effects | ||
| color enhancement | ||
| euphoria | ||
| hospital | ||
| sweating | ||
| empathy | ||
| dissociation | ||
| body high |
Dosage Distribution
Dose distribution from experience reports
Real-World Dose Distribution
62K DosesFrom 43 individual dose entries
Oral (n=37)
Common Combinations
Most co-occurring substances in experience reports
Form / Preparation
Most common forms and preparations reported
Body-Weight Dosing
Dose relative to body weight from reports with weight data
Redose Patterns
Redosing behavior across 28 reports