Two cases of neuroleptic-induced prolonged extrapyramidal symptoms

Neuroleptic-induced extrapyramidal symptoms (EPS) are generally categorized as acute, withdrawal and tardive EPS. Here, we report two cases of a unique late-onset, long-lasting EPS (e.g., prolonged EPS); in those cases, EPS appeared a few months following initiation of haloperidol and lasted for a few months after significant reduction or complete withdrawal of neuroleptics. Case 1, a 41-year-old female, began to exhibit EPS such as bradykinesia, rigidity and parkinsonian gait 4 months after the haloperidol treatment. Her rigidity was ameliorated by a reduction of haloperidol; however, reduction of neuroleptics made it difficult for her to maintain a seated posture because of an imbalance of muscle tonus. Her EPS continued for 9 months even after haloperidol was switched to very low doses of thioridazine (10 mg/day). Case 2 is a 42-year-old female. She exhibited EPS including dysphagia and a difficulty in opening her mouth 3 months after the haloperidol treatment began. Her EPS lasted for 45 days, even after complete withdrawal of neuroleptics. The EPS observed in these two cases occurred even after prolactin levels became normal. "Prolonged EPS" is a unique subclass of neuroleptic-induced reversible EPS that might involve the coexistence of hypo- and hyper-dopaminergic transmission, especially in patients who show very low tolerance to neuroleptics.