The most common adverse events in these groups were dyskinesia ( seven [ 8 % ] of 84 patients in the placebo group , 13 [ 16 % ] of 82 in the 120 mg twice-daily group , and 17 [ 20 % ] of 85 in the 180 mg twice-daily group ) , nausea ( three [ 4 % ] , 9 [ 11 % ] , and ten [ 12 % ] ) , and dizziness ( one [ 1 % ] , four [ 5 % ] , and 11 [ 13 % ] ) .