Impact of CYP2D6 and CYP2C19 Genetic Variations on Venlafaxine Treatment Outcomes: Insights from Norwegian and UK Cohorts

Highlight

• Venlafaxine metabolism primarily involves CYP2D6, with CYP2C19 playing a secondary role.
• CYP2D6 poor metabolizers (PMs) consistently show increased odds of venlafaxine treatment failure in both Norwegian and UK cohorts.
• Dual CYP2D6 and CYP2C19 PM status drastically increases the risk of switching antidepressants, suggesting augmented treatment failure.
• Pre-emptive pharmacogenetic testing could optimize venlafaxine therapy and reduce treatment failure.