OBJECTIVES: To perform a cost-utility analysis of lacosamide as add-on therapy to standard antiepileptic drugs (AEDs) compared to standard AEDs alone based on individual patients data derived from actual clinical practice in the Czech Republic METHODS: Based on retrospective data collection of 409 patients with epilepsy treated with lacosamide for 6 months in actual clinical practice, we developed a cost-utility Markov cohort model. The model has 4 basic health states defined by number of seizures within 3 months plus 1 state represented by occurrence of severe side effects and 1 absorption state; death. Each health state was described by utility levels derived from literature. Transition probabilities for the first cycle were derived from observational study data and subsequently published literature. The model time-horizon was 20 years, 1 cycle length covered 3 months, and a 3% discount rate was used for costs and outcomes (Quality adjusted life years (QALYs)). Only costs attributed to drug acquisition were calculated, dosing of each AED was derived from the retrospective study. We performed probabilistic sensitivity analysis (PSA) with 3000 iterations using a willingness to pay (WTP) threshold equal to 3 times GDP per capita (43,000 EUR) in the Czech Republic. RESULTS: Over a 20 year time-horizon, add-on lacosamide generated 11.47 QALYs and costs 33,439 EUR (per patient), whereas standard AEDs alone provided 11.09 QALYs and costs 22,916 EUR (per patient), respectively. The base-case ICER was calculated as 27,692 EUR/QALY. Based on the PSA and its cost-effectiveness acceptability curve (CEAC) we calculated that add-on lacosamide has a probability of cost-effectiveness at 43,000 EUR per QALY gained of 80.2% compared to standard AEDs alone. CONCLUSIONS: Based on data from clinical practice lacosamide as add-on treatment in patients with partial-onset seizures is cost-effective under the WTP threshold implicitly applied in the Czech Republic.