Paroxetine-d₆is intended for use as an internal standard for the quantification of paroxetine by GC- or LC-MS. Paroxetine is a selective serotonin reuptake inhibitor (SSRI; K_i= 0.04 nM).¹It is selective for the serotonin transporter (SERT) over the dopamine and norepinephrine transporters (K_is = 400 and 90 nM, respectively) as well as the serotonin (5-HT) receptor subtypes 5-HT_1Aand 5-HT_2A, the histamine H₁receptor, α₁- and α₂-adrenergic receptors (α₂-ARs), and muscarinic acetylcholine receptors (mAChRs; K_is = 21,168, 6,320, 13,746, 995, 3,915, and 42 nM, respectively).^1,2Paroxetine (5 mg/kg) decreases immobility time in the forced swim test in mice.³Formulations containing paroxetine have been used in the treatment of depression, obsessive-compulsive disorder (OCD), panic disorder, social and generalized anxiety disorders, and post-traumatic stress disorder (PTSD).

1.Mattson, R.J., Catt, J.D., Denhart, D.J., et al.Conformationally restricted homotryptamines. 2. Indole cyclopropylmethylamines as selective serotonin reuptake inhibitorsJ. Med. Chem.48(19)6023-6034(2005) 2.Owens, M.J., Neal, W., Plott, S.J., et al.Neurotransmitter receptor and transporter binding profile of antidepressants and their metabolitesJ. Pharmacol. Exp. Ther.283(3)1305-1322(1997) 3.Sugimoto, Y., Tagawa, N., Kobayashi, Y., et al.Involvement of the sigma1 receptor in the antidepressant-like effects of fluvoxamine in the forced swimming test in comparison with the effects elicited by paroxetineEur. J. Pharmacol.696(1-3)96-100(2012)