Pitch perception shift: a rare side-effect of carbamazepine.

Carbamazepine-induced pitch perception shifts have rarely been described. Two cases of shifted pitch perception developing during medication with carbamazepine are described. Case 1 possessed absolute pitch. Her pitch perception shift disappeared with the discontinuance of carbamazepine. Case 2 did not have absolute pitch. Even though he experienced a pitch perception shift, he developed a tolerance to the shift. We concluded that carbamazepine was the cause of the pitch perception shift in the first case, while the second case probably became attuned to the change in pitch perception because he did not possess absolute pitch.