Healthy , White , male volunteers ( n = 36 ) who were not poor metabolizers of CYP2C19 were randomized to treatment A ( single-dose 40 mg omeprazole on days 1 and 8 together with 6 days of multiple-dose lacosamide [ 200-600 mg/day ] on days 3-8 ) and treatment B ( single doses of 300 mg lacosamide on days 1 and 8 with 7 days of 40 mg/day omeprazole on days 3-9 ) in pseudorandom order , separated by a 7-day washout period .