For the treatment of refractory focal seizures (RFS), the antileptic drug, Levetiracetam has manifested good efficacy and tolerability. The anti-epileptic effect of the drug is most likely due to its binding to synaptic vesicle protein 2a (SV2A), located in presynaptic membranes, modulating the calcium-dependent exocytosis of neurotransmitters into the synaptic gap. 

In contrast, Brivaracetam is a highly selective and reversible SV2A ligand having a 15- to 30-fold higher affinity compared to the affinity of Levetiracetam in the human brain. Studies have indicated that Brivaracetam can also be effective and well tolerated as adjunctive therapy in patients with RFS.

• A clinical study was conducted to evaluate the efficacy and tolerability of Levetiracetam and Brivaracetam in adults with RFS. The study revealed that both Levetiracetam and Brivaracetam, at various doses, were effective for treating patients with RFS. The maximum efficacy of both drugs seemed to be restricted at the middle dose because the high dose of both drugs (3000 mg Levetiracetam and 200 mg Brivaracetam) did not show higher efficacy than the middle dose. 
• Furthermore, the majority of statistical differences for adverse effects and the withdrawal of Levetiracetam and Brivaracetam were found at the middle-dose levels, suggesting a dose of more than 2000 mg/d Levetiracetam and 100 mg/d Brivaracetam should be administered cautiously. 

The study thus inferred that Levetiracetam might be slightly more effective with a lower probability of dizziness compared with Brivaracetam for patients with RFS.