A 38-year-old man with schizophrenia has been on risperidone 6 mg/day for 8 months. He presents with involuntary orofacial movements, tongue protrusion, and lip smacking that began 2 weeks ago. Vital signs are normal, temperature is 37.2°C, and creatine kinase is 180 U/L. What is the most appropriate next step in management?

Explanation

## Clinical Presentation & Diagnosis The patient presents with **tardive dyskinesia (TD)** — involuntary orofacial movements (tongue protrusion, lip smacking) that emerged after prolonged antipsychotic exposure (8 months on risperidone). Normal temperature and CK exclude neuroleptic malignant syndrome (NMS). **Key Point:** Tardive dyskinesia is a late-onset extrapyramidal side effect (typically after 3–6 months of antipsychotic use) caused by dopamine receptor supersensitivity in the basal ganglia. Unlike acute dystonia or akathisia, it does NOT respond to anticholinergics and may worsen with them. ## Management Algorithm for Tardive Dyskinesia ```mermaid flowchart TD A[Tardive dyskinesia diagnosed]:::outcome --> B{Can antipsychotic be discontinued?}:::decision B -->|Yes, stable psychosis| C[Discontinue antipsychotic]:::action B -->|No, active psychosis| D[Switch to atypical with lower TD risk]:::action C --> E[Observe for 2-3 months]:::action D --> F[Consider clozapine or quetiapine]:::action E --> G[TD may resolve spontaneously]:::outcome G --> H{Persistent TD?}:::decision H -->|Yes| I[Add tetrabenazine or valbenazine]:::action ``` ## Why NOT Anticholinergics? **Warning:** Benztropine and trihexyphenidyl are **contraindicated** in tardive dyskinesia. Anticholinergics: - Do NOT treat TD (it is not an acute dystonia) - May **worsen** involuntary movements by increasing dopamine activity - Are appropriate only for acute dystonia or parkinsonism, not late-onset dyskinesia ## Correct Management Strategy **High-Yield:** The gold standard for TD management is **antipsychotic discontinuation** if the clinical situation permits (stable psychosis, no acute relapse risk). This allows: 1. Reversal of dopamine supersensitivity 2. Spontaneous resolution in 30–50% of cases over 2–3 months 3. Prevention of further worsening If discontinuation is not possible (active psychosis), switch to **clozapine** (lowest TD risk among antipsychotics) or a low-potency atypical agent. ## Why NOT Dose Reduction or Propranolol? Dose reduction alone is insufficient; the underlying pathology (receptor supersensitivity) persists. Propranolol has limited evidence in TD. ## Why NOT Immediate Switch to Clozapine? This patient's psychosis appears stable (no mention of relapse or acute symptoms). Discontinuation with observation is the first-line approach; clozapine is reserved for cases where antipsychotic continuation is mandatory. [cite:Stahl's Essential Psychopharmacology 6e Ch 8; Kaplan & Sadock 21e Ch 29]