The main goal of this study is to determine if lacosamide can reduce the amount of opioids required in patient's undergoing a total hip arthroplasty. Lacosamide is a FDA approved medication for the treatment of partial-onset seizures and is a man-made amino acid (usually are used as the building blocks from which proteins are made in the body) which block special proteins inby a change in the electricity that a cell may feel (voltage-gated sodium channel). Lacosamide is a new antiepileptic drug apparently lacking any major pharmacokinetic interactions (how the body affects a specific drug after administration, as well as the chemical changes of the substance in the body, and the effects and routes of excretion of the metabolites of the drug).