Switching carbamazepine to lacosamide improves gamma-glutamyl transpeptidase levels

Carbamazepine (CBZ) use has been limited by multiple adverse reactions. Lacosamide (LCM) is a functional amino acid anti-seizure medication (ASM), approved for focal seizure patients more than 4 years old. It is non-inferior in terms of efficacy to controlled release CBZ and was proven to have better tolerability. This study examines the effect of abruptly changing CBZ to LCM in epilepsy patients with elevated gamma-glutamyl transpeptidase (GGT). Consenting adult patients aged 18 years old and above, with controlled focal seizure disorder for more than 2 years, who were consistently taking CBZ and who had elevated GGT were included in this study. Out of 1526 patients screened, only 12 satisfied the inclusion criteria. After abruptly changing CBZ to LCM, the GGT level significantly dropped from a median of 141.5 to 63.5 IU/L (z = 3.06, p = 0.0005). Moreover, there was significantly lower proportion of patients with abnormal GGT levels after the switch in medications was done (100% vs. 66.7%, McNemar χ² = 8, p = 0.008). Moderate to high levels of GGT in patients with focal epilepsy can be decreased by changing CBZ to LCM. Moreover, abruptly changing CBZ to LCM without cross-titration may be safe and effective in preventing seizure incidence within a 1-month period. PLAIN LANGUAGE SUMMARY: Although carbamazepine (CBZ) is the standard drug for focal seizures, its numerous side effects, especially in the liver, limits its use in a lot of patients with epilepsy. Gamma-glutamyl transferase (GGT), which is elevated in liver disease of whatever cause including intake of CBZ, is associated with increased mortality. In this study, we found that abruptly changing CBZ to Lacosamide (LCM) can significantly decrease the GGT level in 1 month without apparent increase in seizure recurrence and side effects. Therefore, we conclude that high levels of GGT may be decreased by abruptly changing CBZ to LCM.