Atomoxetine

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Atomoxetine
Atomoxetine structure.svg
Atomoxetine3Dan.gif
Systematic (IUPAC) name
(3R)-N-methyl-3-(2-methylphenoxy)-3-phenylpropan-1-amine; (R)-N-methyl-3-phenyl-3-(o-tolyloxy)propan-1-amine
Clinical data
Trade names Strattera
AHFS/Drugs.com monograph
MedlinePlus a603013
Pregnancy cat. B3 (AU) C (US)
Legal status Prescription Only (S4) (AU) -only (CA) POM (UK) -only (US)
Routes Oral
Pharmacokinetic data
Bioavailability 63 to 94%[1][2][3]
Protein binding 98%[1][2][3]
Metabolism Hepatic, via CYP2D6[1][2][3]
Half-life 5.2 hours[1][2][3]
Excretion Renal (80%) and faecal (17%)[1][2][3]
Identifiers
CAS number 83015-26-3 N
ATC code N06BA09
PubChem CID 54841
DrugBank DB00289
ChemSpider 49516 YesY
UNII ASW034S0B8 YesY
KEGG D07473 YesY
ChEBI CHEBI:127342 YesY
ChEMBL CHEMBL641 YesY
Chemical data
Formula C17H21NO 
Mol. mass 255.36 g/mol
291.81 g/mol (hydrochloride)
 N (what is this?)  (verify)

Atomoxetine (brand name: Strattera) is a drug approved for the treatment of attention-deficit hyperactivity disorder (ADHD).[4] It is a selective norepinephrine reuptake inhibitor (NRI),[4] not to be confused with serotonin norepinephrine reuptake inhibitors (SNRIs) or selective serotonin reuptake inhibitors (SSRIs), both of which are currently the most prescribed form of antidepressants.[5]

Medical use[edit]

Attention deficit-hyperactivity disorder[edit]

Classified as a norepinephrine (noradrenaline) reuptake inhibitor, atomoxetine is approved for use in children, adolescents, and adults.[4] However, its efficacy has not been studied in children under six years old.[2] Its primary advantage over the standard stimulant treatments for ADHD is that it has no abuse potential.[2]

The initial therapeutic effects of atomoxetine usually take 2–4 weeks to be become apparent.[1] A further 2–4 weeks may be required for the full therapeutic effects to be seen.[5] Its efficacy may be less than that of stimulant medications.[6]

Unlike α2 adrenoceptor agonists such as guanfacine and clonidine atomoxetine's use can be abruptly stopped without significant withdrawal effects being seen.[2]

Investigational uses[edit]

There has been some suggestion that atomoxetine might be a helpful adjunct in patients with major depression, especially in cases where ADHD occurs comorbidly to major depression.[7][8][9] Several randomised double-blind placebo-controlled trials found that atomoxetine was an efficacious treatment for various disorders like paediatric nocturnal enuresis,[10] binge eating disorder,[11] and is an efficacious weight loss medication.[12]

Adverse effects[edit]

Incidence of adverse effects:[2][3][13][14]

Very common (>10% incidence) adverse effects include:

  • Nausea (26%)
  • Xerostomia (dry mouth) (20%)
  • Appetite loss (16%)
  • Insomnia (15%)
  • Fatigue (10%)
  • Headache
  • Cough

Common (1-10% incidence) adverse effects include:

  • Constipation (8%)
  • Dizziness (8%)
  • Erectile dysfunction (8%)
  • Somnolence (8%)
  • Abdominal pain (7%)
  • Urinary hesitation (6%)
  • Tachycardia (high heart rate) (5-10%)
  • Hypertension (high blood pressure) (5-10%)
  • Irritability (5%)
  • Abnormal Dreams (4%)
  • Dyspepsia (4%)
  • Ejaculation disorder (4%)
  • Hyperhidrosis (4%)
  • Vomiting (4%)
  • Hot flashes (3%)
  • Paraesthesia (3%)
  • Menstrual disorder (3%)
  • Weight loss (2%)
  • Depression
  • Sinus headache
  • Dermatitis
  • Mood swings

Uncommon (0.1-1% incidence) adverse effects include:

  • Suicide-related events
  • Hostility
  • Emotional lability
  • Aggression
  • Psychosis
  • Syncope
  • Tremor
  • Migraine
  • Hypoaesthesia
  • Seizure
  • Palpitations
  • Sinus tachycardia
  • QT interval prolongation
  • Increased blood bilirubin
  • Allergic reactions

Rare (0.01-0.1% incidence) adverse effects include:

The FDA of the US has issued a black box warning for suicidal behaviour/ideation.[3] Similar warnings have been issued in Australia.[2][16] Unlike stimulant medications atomoxetine does not have abuse liability or the potential to cause withdrawal effects on abrupt discontinuation.[2]

Contraindications[edit]

Contraindications include:[2]

  • Hypersensitivity to atomoxetine or any of the excipients in the product
  • Symptomatic cardiovascular disease including:
-moderate to severe hypertension
-atrial fibrillation
-atrial flutter
-ventricular tachycardia
-ventricular fibrillation
-or ventricular flutter
-advanced arteriosclerosis
  • Severe cardiovascular disorders
  • Narrow angle glaucoma
  • Poor metabolisers (due to the metabolism of atomoxetine by CYP2D6)

Interactions[edit]

Atomoxetine is a substrate for CYP2D6 and hence concurrent treatment with CYP2D6 inhibitors or inducers is not recommended as this can lead to significant elevations or reductions of plasma atomoxetine levels, respectively.[2] Other possible drug interactions include with:[2]

  • Antihypertensive and pressor agents, due to the potential pressor effect of indirect sympathomimetics such as atomoxetine.
  • Norepinephrine-acting agents such as α1 adrenoceptor agonists or norepinephrine reuptake inhibitors due to the potential for additive or synergistic pharmacologic effects.
  • β-adrenoceptor agonists due to the potential for the effects of these drugs to be potentiated by atomoxetine.
  • Tricyclic antidepressants as they may potentiate the cardiovascular effects of atomoxetine.
  • Highly plasma protein-bound drugs due to the potential of atomoxetine to displace these drugs from plasma proteins and hence potentiate their adverse effects. Examples include diazepam, paroxetine and phenytoin.

Overdose[edit]

Atomoxetine is relatively non-toxic in overdose as single-drug overdoses involving over 1500 mg of atomoxetine have not resulted in death.[2] The most common symptoms of overdose include:[2]

  • Gastrointestinal symptoms
  • Somnolence
  • Dizziness
  • Tremor
  • Abnormal behaviour
  • Hyperactivity
  • Agitation
  • Dry mouth
  • Tachycardia
  • Hypertension
  • Mydriasis

and less commonly:[2]

  • Seizures

Recommended treatment of overdoses include activated charcoal treatment to prevent further absorption of the drug.[2]

Detection in biological fluids[edit]

Atomoxetine may be quantitated in plasma, serum or whole blood in order to distinguish extensive versus poor metabolizers in those receiving the drug therapeutically, to confirm the diagnosis in potential poisoning victims or to assist in the forensic investigation in a case of fatal overdosage.[17]

Chemistry and composition[edit]

Atomoxetine is designated chemically as (−)-N-methyl-3-phenyl-3-(o-tolyloxy)-propylamine hydrochloride, and has a molecular mass of 291.82.[4] It has a solubility of 27.8 mg/mL in water.[4] Atomoxetine is a white solid that exists as a granular powder inside the capsule, along with pre-gelatinized starch and dimethicone.[4] The capsule shells contain gelatin, sodium lauryl sulfate, FD&C Blue No. 2, synthetic yellow iron oxide, titanium dioxide, red iron oxide, edible black ink, and trace amounts of other inactive ingredients.[4]

Pharmacology[edit]

Atomoxetine inhibits NET, SERT and DAT with respective Ki values of 5, 77 and 1451 nM.[18] In microdialysis studies it increased NE and DA levels by 3 fold in the prefrontal cortices but did not alter DA levels in the striatum or nucleus accumbens.[19] Atomoxetine also acts as an NMDA-receptor antagonist at clinically relevant doses.[20] The role of NMDA-receptor antagonism in atomoxetine's therapeutic profile remains to be further elucidated, but recent literature has further implicated glutaminergic dysfunction as central in ADHD pathophysiology and etiology.[21][22]

4-hydroxyatomoxetine, the principle metabolite of atomoxetine, exhibits affinity for μ-opioid receptors and κ-opioid receptors. Creighton et al. reported no activation of μ-opioid receptors and a partial agonist effect at κ-opioid receptors.[23] The clinical significance of these effects are not known.

Atomoxetine has been found to inhibit both brain and cardiac GIRKs, a characteristic it shares with the norepinephrine reuptake inhibitor reboxetine.[24]

Binding profile[18][19][23][25]

Protein Ki (nM) for atomoxetine Ki (nM) for 4-hydroxyatomoxetine
SERT 77  ?
NET 5  ?
DAT 1451  ?
5-HT receptors >1000  ?
Alpha adrenergic receptors >1000  ?
Beta adrenergic receptors >1000  ?
D1 & D2 >1000  ?
M1 & M2 >1000  ?
H1 & H2 >1000  ?
δ1 opioid receptor  ? 300
κ1 opioid receptor  ? 95
μ opioid receptor  ? 422
σ1 receptor >1000  ?

Synthesis[edit]

First step appears to be a Mannich reaction between acetophenone, paraformaldehyde and dimethylamine, although not formally written in the scheme. Atomoxetine synthesis.png

Foster, B. J.; Lavagnino, E. R.; European Patent, 1982, EP 0052492 .

History[edit]

This compound is manufactured, marketed and sold in the United States under the brand name Strattera by Eli Lilly and Company as a hydrochloride salt (atomoxetine HCl), the original patent filing company, and current U.S. patent owner. There is currently no generic manufactured directly in the United States since it is under patent until 2017.[26] On 12 August 2010, Lilly lost a lawsuit that challenged Lilly's patent on Strattera, increasing the likelihood of an earlier entry of a generic into the US market.[27] On 1 September 2010, Sun Pharmaceuticals announced it would begin manufacturing a generic in the United States.[28] In a 29 July 2011 conference call, however, Sun Pharmaceutical's Chairman stated "Lilly won that litigation on appeal so I think [generic Strattera]’s deferred."[29]

Production and brand-names[edit]

In India, Atomoxetine is found under different names like Tomoxetin, Attentrol, Axepta, Atokem and Attentin.

References[edit]

  1. ^ a b c d e f "atomoxetine (Rx) - Strattera". Medscape Reference. WebMD. Retrieved 10 November 2013. 
  2. ^ a b c d e f g h i j k l m n o p q r "STRATTERA® (atomoxetine hydrochloride)". TGA eBusiness Services. Eli Lilly Australia Pty. Limited. 21 August 2013. Retrieved 10 November 2013. 
  3. ^ a b c d e f g "ATOMOXETINE HYDROCHLORIDE capsule [Mylan Pharmaceuticals Inc.]". DailyMed. Mylan Pharmaceuticals Inc. October 2011. Retrieved 10 November 2013. 
  4. ^ a b c d e f g "STRATTERA® (atomoxetine hydrochloride) CAPSULES for Oral Use. Full Prescribing Information." Eli Lilly and Company, 2002, 2013. Revised 5 August 2013. [1]
  5. ^ a b Taylor, D; Paton, C; Shitij, K (2012). The Maudsley prescribing guidelines in psychiatry (in English). West Sussex: Wiley-Blackwell. ISBN 978-0-470-97948-8.  edit
  6. ^ Kooij, JJS (2013). Adult ADHD Diagnostic Assessment and Treatment (PDF). Springer London. doi:10.1007/978-1-4471-4138-9. ISBN 9781447141372. 
  7. ^ Spencer TJ, Faraone SV, Michelson D, Adler, LA; Reimherr, FW; Glatt, SJ; Biederman, J (March 2006). "Atomoxetine and adult attention-deficit/hyperactivity disorder: the effects of comorbidity". The Journal of Clinical Psychiatry 67 (3): 415–20. doi:10.4088/JCP.v67n0312. PMID 16649828. 
  8. ^ Carpenter LL, Milosavljevic N, Schecter JM, Tyrka AR, Price LH (October 2005). "Augmentation with open-label atomoxetine for partial or nonresponse to antidepressants". The Journal of Clinical Psychiatry 66 (10): 1234–8. doi:10.4088/JCP.v66n1005. PMID 16259536. 
  9. ^ Kratochvil CJ, Newcorn JH, Arnold LE, Duesenberg, D; Emslie, GJ; Quintana, H; Sarkis, EH; Wagner, KD; Gao, H; Michelson, D; Biederman, J (September 2005). "Atomoxetine alone or combined with fluoxetine for treating ADHD with comorbid depressive or anxiety symptoms". Journal of the American Academy of Child and Adolescent Psychiatry 44 (9): 915–24. doi:10.1097/01.chi.0000169012.81536.38. PMID 16113620. 
  10. ^ Sumner, CR; Schuh, KJ; Sutton, VK; Lipetz, R; Kelsey, DK (December 2006). "Placebo-controlled study of the effects of atomoxetine on bladder control in children with nocturnal enuresis". Journal of Child and Adolescent Psychopharmacology 16 (6): 699–711. doi:10.1089/cap.2006.16.699. PMID 17201614. 
  11. ^ McElroy, SL; Guerdjikova, A; Kotwal, R; Welge, JA; Nelson, EB; Lake, KA; Keck, PE Jr; Hudson, JI (March 2007). "Atomoxetine in the treatment of binge-eating disorder: a randomized placebo-controlled trial". The Journal of Clinical Psychiatry 68 (3): 390–8. doi:10.4088/JCP.v68n0306. PMID 17388708. 
  12. ^ Gadde, KM; Yonish, GM; Wagner, HR; Foust, MS; Allison, DB (July 2006). "Atomoxetine for weight reduction in obese women: a preliminary randomised controlled trial". International Journal of Obesity 30 (7): 1138–42. doi:10.1038/sj.ijo.0803223. PMID 16418753. 
  13. ^ "Strattera 10mg, 18mg, 25mg, 40mg, 60mg, 80mg or 100mg hard capsules". electronic Medicines Compendium. 28 May 2013. Retrieved 10 November 2013. 
  14. ^ "Strattera Product Insert". Retrieved 8 December 2013. 
  15. ^ "STRATTERA Medication Guide". Eli Lilly and Company. 2003. Retrieved 17 December 2013. 
  16. ^ "Atomoxetine and suicidality in children and adolescents". Australian Prescriber 36 (5). October 2013. p. 166. Retrieved 10 November 2013. 
  17. ^ Baselt, Randall C. (2008). Disposition of Toxic Drugs and Chemicals in Man (8th ed.). Foster City, CA: Biomedical Publications. pp. 118–20. ISBN 0-931890-08-X. 
  18. ^ a b Roth, BL; Driscol, J (12 January 2011). "PDSP Ki Database". Psychoactive Drug Screening Program (PDSP). University of North Carolina at Chapel Hill and the United States National Institute of Mental Health. Retrieved 10 November 2013. 
  19. ^ a b Bymaster, FP; Katner, JS; Nelson, DL; Hemrick-Luecke, SK; Threlkeld, PG; Heiligenstein, JH; Morin, SM; Gehlert, DR; Perry, KW (November 2002). "Atomoxetine Increases Extracellular Levels of Norepinephrine and Dopamine in Prefrontal Cortex of Rat: A Potential Mechanism for Efficacy in Attention Deficit/Hyperactivity Disorder" (PDF). Neuropsychopharmacology 27 (5): 699–711. doi:10.1016/S0893-133X(02)00346-9. PMID 12431845. 
  20. ^ Ludolph, AG; Udvardi, PT; Schaz, U; Henes, C; Adolph, O; Weigt, HU; Fegert, JM; Boeckers, TM; Föhr, KJ (May 2010). "Atomoxetine acts as an NMDA receptor blocker in clinically relevant concentrations" (PDF). British Journal of Pharmacology 160 (2): 283–291. doi:10.1111/j.1476-5381.2010.00707.x. PMC 2874851. PMID 20423340. 
  21. ^ Lesch, KP; Merker, S; Reif, A; Novak, M (June 2013). "Dances with black widow spiders: dysregulation of glutamate signalling enters centre stage in ADHD". European Neuropsychopharmacology 23 (6): 479–491. doi:10.1016/j.euroneuro.2012.07.013. PMID 22939004. 
  22. ^ Children's Hospital of Philadelphia: New gene study of ADHD points to defects in brain signaling pathways
  23. ^ a b Creighton, CJ; Ramabadran, K; Ciccone, PE; Liu, J; Orsini, MJ; Reitz, AB (2 August 2004). "Synthesis and biological evaluation of the major metabolite of atomoxetine: elucidation of a partial kappa-opioid agonist effect.". Bioorganic & medicinal chemistry letters 14 (15): 4083–5. PMID 15225731. 
  24. ^ Kobayashi, T; Washiyama, K; Ikeda, K (Jun 2010). "Inhibition of G-protein-activated inwardly rectifying K+ channels by the selective norepinephrine reuptake inhibitors atomoxetine and reboxetine.". Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 35 (7): 1560–9. PMID 20393461. 
  25. ^ Bymaster, FP; Katner, JS; Nelson, DL; Hemrick-Luecke, SK; Threlkeld, PG; Heiligenstein, JH; Morin, SM; Gehlert, DR; Perry, KW (November 2002). "Atomoxetine increases extracellular levels of norepinephrine and dopamine in prefrontal cortex of rat: a potential mechanism for efficacy in attention deficit/hyperactivity disorder". Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 27 (5): 699–711. doi:10.1016/S0893-133X(02)00346-9. PMID 12431845. 
  26. ^ "Patent and Exclusivity Search Results". Electronic Orange Book. US Food and Drug Administration. Retrieved 26 April 2009. 
  27. ^ "Drugmaker Eli Lilly loses patent case over ADHD drug, lowers revenue outlook". Chicago Tribune. 
  28. ^ "Sun Pharma receives USFDA approval for generic Strattera capsules". International Business Times. 
  29. ^ "Sun Pharma Q1 2011-12 Earnings Call Transcript 10.00 am, July 29, 2011". 

External links[edit]