Eight RCTs (2,732 patients) were included in the review. All studies were considered to be at low risk of bias from incomplete reporting of outcome data and selective reporting. Allocation concealment was described in five trials. All studies were at unclear risk of bias due to blinding.
Eslicarbazepine acetate (four RCTs): Eslicarbazepine acetate was associated with increased dizziness at 800mg/day (RD 0.14, 95% CI 0.08 to 0.19; I²=13%; three RCTs) and at 1,200mg/day was associated with increased diplopia (RD 0.07, 95% CI 0.03 to 0.10; I²=57%; three RCTs), nausea (RD 0.08, 99% CI 0.02 to 0.14; I²=52%; three RCTs) and vertigo (RD 0.04, 95% CI 0.01 to 0.08; I²=0%; two RCTs). Conflicting results were reported for eslicarbazepine acetate 1,200mg/day and dizziness but it appeared that dizziness may have been increased at this dose (RD 0.17, 95% CI 0.02 to 0.32; I²=93%; four RCTs).
Lacosamide (three RCTs): Lacosamide 200mg/day was associated with increased dizziness (RD 0.09, 95% CI 0.04 to 0.14; I²=56%; two RCTs), vertigo (RD 0.05, 95% CI 0.01 to 0.09; one RCT) and diplopia (RD 0.05, 95% CI 0.02 to 0.08; I²=60%; two RCTs). Lacosamide 400mg/day was associated with increased dizziness (RD 0.19, 0.06 to 0.32; I²=86%; three RCTs), ataxia/abnormal co-ordination (RD 0.08, 95 %CI 0.05 to 0.11; I²=0%; three RCTs), diplopia (RD 0.08, 95% CI 0.05 to 0.12, I²=0%; three RCTs), nausea (RD 0.07, 99% CI 0.02 to 0.11; I²=0%; three RCTs) and vomiting (RD 0.06, 99% CI 0.02 to 0.10; I²=0%; three RCTs).
Oxcarbazepine (one RCT): Oxcarbazepine 600mg/day was associated with increased dizziness, diplopia and vomiting. Oxcarbazepine 1,200mg/day was associated with increased somnolence, dizziness, vertigo, ataxia/abnormal co-ordination, diplopia, nystagmus, nausea and vomiting.
Risk of withdrawals due to adverse events increased with higher doses of all antiepileptic drugs compared to placebo.
Indirect comparisons showed that adverse events were more frequently reported with oxcarbazepine than lacosamide or eslicarbazepine acetate. Numbers needed to harm were reported in the review.