A client with schizophrenia receives a prescription for fluphenazine. Which instruction is most important for the nurse to include when teaching the client about this drug?

Fluphenazine is a first-generation (typical) antipsychotic, and a serious, potentially irreversible side effect is tardive dyskinesia, which is characterized by involuntary movements of the tongue, face, and limbs. Early identification and reporting are critical as discontinuation of the medication may prevent the condition from becoming permanent. While increased thirst (A), photosensitivity (B), and orthostatic hypotension (which would cause a decrease, not an increase, in blood pressure) (D) are possible side effects, they are not as serious or irreversible as tardive dyskinesia.