Neuroleptic malignant syndrome after haloperidol and fentanyl infusion in a patient with cancer with severe mineral imbalance

This case report describes a terminally ill patient with cancer with severe hypophosphataemia, hypocalcemia, and hypomagnesemia who developed neuroleptic malignant syndrome after administration of a combination of haloperidol and fentanyl. The chief etiology of neuroleptic malignant syndrome in this patient was administration of haloperidol, but fentanyl and coexisting mineral imbalance could have contributed to development of the syndrome. Palliative care clinicians should be aware that neuroleptic malignant syndrome can occur in their patients receiving haloperidol.