Norepinephrine–dopamine disinhibitor explained

Norepinephrine and dopamine disinhibitors (NDDIs) are a class of drugs which act at specific sites to disinhibit downstream norepinephrine and dopamine release in the brain.^[1]

Agomelatine, an antidepressant which disinhibits norepinephrine and dopamine release in the frontal cortex by antagonizing 5-HT_2C receptors,^[2] was the first drug to be described as an NDDI.^[3] While many other drugs also antagonize 5-HT_2C receptors to some degree or another, they tend to be very non-specific in their actions, and as a result, the term "NDDI" has generally, though not always (for instance, fluoxetine has been called an NDDI in addition to SSRI due to its (weak) blockade of 5-HT_2C),^[4] been reserved for describing newer, more selective agents in which disinhibition of norepinephrine and dopamine release is their primary mechanism of action.

Another drug that has been referred to as an NDDI in the medical literature is flibanserin,^[5] which is approved as a treatment for hypoactive sexual desire disorder in premenopausal women.^[6] Flibanserin disinhibits norepinephrine and dopamine release in the prefrontal cortex by activating 5-HT_1A receptors in this area.^[7]

Aside from agomelatine, fluoxetine, flibanserin and mirtazapine, as of present, no other drugs have been described as NDDIs in the medical literature, despite the fact that many other existing drugs possess effects consistent with those of the definition of an NDDI. In any case, more drugs labeled specifically as NDDIs may be seen in the future.

See also

• Noradrenergic and specific serotonergic antidepressant (NaSSA)
• Serotonin antagonist and reuptake inhibitor (SARI)
• Serotonin modulator and stimulator (SMS)

Notes and References

1. Book: Ian P. Stolerman . Encyclopedia of Psychopharmacology . 23 April 2012 . 30 August 2010 . Springer . 978-3-540-68698-9 . 105.
2. Millan MJ, Gobert A, Lejeune F, etal . The novel melatonin agonist agomelatine (S20098) is an antagonist at 5-hydroxytryptamine2C receptors, blockade of which enhances the activity of frontocortical dopaminergic and adrenergic pathways . The Journal of Pharmacology and Experimental Therapeutics . 306 . 3 . 954–64 . September 2003 . 12750432 . 10.1124/jpet.103.051797 . 18753440 . subscription .
3. Stahl SM . Novel mechanism of antidepressant action: norepinephrine and dopamine disinhibition (NDDI) plus melatonergic agonism . The International Journal of Neuropsychopharmacology . 10 . 5 . 575–8 . October 2007 . 17681087 . 10.1017/S1461145707008000 . 15836774 . free .
4. Book: Stephen M. Stahl . Depression and Bipolar Disorder: Stahl's Essential Psychopharmacology . 23 April 2012 . 27 March 2008 . Cambridge University Press . 978-0-521-88663-5 . 80.
5. Book: Stephen M. Stahl . S. M. Stahl . Stahl's Essential Psychopharmacology: Neuroscientific Basis and Practical Applications . registration . 23 April 2012 . 17 March 2008 . Cambridge University Press . 978-0-521-67376-1 . 658.
6. Thorp J, Simon J, Dattani D, etal . Treatment of hypoactive sexual desire disorder in premenopausal women: efficacy of flibanserin in the DAISY study . The Journal of Sexual Medicine . 9 . 3 . 793–804 . March 2012 . 22239862 . 10.1111/j.1743-6109.2011.02595.x .
7. Stahl SM, Sommer B, Allers KA . Multifunctional pharmacology of flibanserin: possible mechanism of therapeutic action in hypoactive sexual desire disorder . The Journal of Sexual Medicine . 8 . 1 . 15–27 . January 2011 . 20840530 . 10.1111/j.1743-6109.2010.02032.x .