Desvenlafaxine (Pristiq), also known as O-desmethy- venlafaxine (ODV), is an active metabolite of venlafaxine (Effexor). Pristiq was introduced to the US market in 2007, thirteen years after the release of Effexor. The European Union did not approve Pristiq because it is probably less effective than Effexor and has no clear advantage over Effexor.
Pristiq is one of the few antidepressants visualized in a bubble, to signify that kinetic interactions are highly unlikely. Pristiq is subject to fewer kinetic interactions than Effexor, but Effexor has relatively low potential for clinically significant interactions anyhow (visualized in a box).
All desvenlafaxine (Pristiq) tablets are extended release (ER), so you don’t have to write “ER” on a desvenlafaxine script. To get ER venlafaxine you must specify “Effexor XR” or “venlafaxine ER”.
Dosing: 50 mg QD is the only recommended dose. The 100 mg dose adds no benefit and is more likely to cause nausea. FDA max is 400 mg QD, which is higher than recommended.
Desvenlafaxine is also available as the brand name Khedezla (released 2014) which is equivalent to Pristiq (2007). Both Pristiq and Khedezla are extended release (ER) formulations of desvenlafaxine, both indicated for major depressive disorder, both dosed once daily. Pristiq is a succinate salt with a half-life of 10.4 hours, while Khedezla is a base with a half-life of 10.6 hours.
The approval of Khedezla was based on the original Pristiq efficacy studies.
Studies have found desvenlafaxine to be ineffective for children with depression (Weihs et al, 2017). “Kid’s desk ain’t for kids.”
Desvenlafaxine has been available generically since 2017.
Dosing: Same as Pristiq