| Indication |
For the treatment of Attention-Deficit/Hyperactivity Disorder
(ADHD) alone or in combination with behavioral treatment, as an adjunct
to psychological, educational, social, and other remedial measures. |
| Pharmacodynamics |
Atomoxetine is the first non-stimulant drug approved for the
treatment of attention-deficit hyperactivity disorder (ADHD).
Atomoxetine is classified as a norepinephrine reuptake inhibitor, and is
approved for use in children, adolescents, and adults. However, its
efficacy has not been studied in children under six years old. Its
advantage over stimulants for the treatment of ADHD is that it has less
abuse potential than stimulants, is not scheduled as a controlled
substance and has proven in clinical trials to offer 24 hour coverage of
symptoms associated with ADHD in adults and children. |
| Mechanism of action |
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. |
| Absorption |
Atomoxetine is rapidly absorbed after oral administration, with
absolute bioavailability of about 63% in EMs and 94% in PMs. Drugs that
elevate gastric pH (magnesium hydroxide/aluminum hydroxide, omeprazole)
have no effect on atomoxetine bioavailability. Absorption is minimally
affected by food. |
| Volume of distribution |
|
| Protein binding |
At therapeutic concentrations, 98% of atomoxetine in plasma is bound to protein, primarily albumin. |
| Metabolism |
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). |
| Route of elimination |
Not Available |
| Half life |
5 hours |
| Clearance |
- 0.35 L/hr/kg [after oral administration in adult extensive metabolizers]
- 0.03 L/hr/kg [administration of atomoxetine to poor metabolizers]
|
| Toxicity |
The most commonly reported symptoms accompanying acute and chronic
overdoses are somnolence, agitation, hyperactivity, abnormal behavior,
and gastrointestinal symptoms. |
