Christensen J et al. – The slightly slower metabolism of lamotrigine in patients receiving lamotrigine with sertraline compared with those receiving lamotrigine alone is not believed to be of clinical significance. However, due to the limited power, the authors may have overlooked a difference that could be clinically relevant.

• The authors identified patients with at least 1 measurement of trough lamotrigine plasma concentration (at steady-state) during lamotrigine therapy and compared dose and plasma concentrations between patients who received lamotrigine with sertraline and patients who received lamotrigine without sertraline.

• The dose corrected concentration of lamotrigine in patients receiving lamotrigine in combination with sertraline was 60.4 μmol/L×1 000/mg/day (SD: 31.1) (N=7) compared to 51.1 μmol/L×1 000/mg/day (SD: 27.6) (N=44) in patients using lamotrigine without sertraline (p=0.42).