Massive creatine kinase elevations with quetiapine: report of two cases.

Massive elevations of serum creatine kinase (CK) can occur in a significant number of patients treated with neuroleptics in the absence of neuroleptic malignant syndrome (NMS). We report two cases of CK-elevations associated with quetiapine treatment, which disappeared after drug discontinuation. To our knowledge, case number one is the first case of quetiapine-induced CK elevation in a neuroleptic-naïve patient. We thus suggest CK assessment when myalgia occurs with neuroleptic treatment.