Regarding the metabolic and neurological side effects of typical antipsychotics, all of the following are true EXCEPT:

## Typical Antipsychotic Adverse Effects: Comparative Analysis ### Movement Disorders Associated with Typical Antipsychotics **Key Point:** Typical antipsychotics cause dose-dependent D₂ blockade in the nigrostriatal pathway, leading to a spectrum of extrapyramidal side effects (EPS). | EPS Type | Onset | Mechanism | Management | |---|---|---|---| | **Acute dystonia** | Minutes to hours | D₂ blockade + relative cholinergic excess | Anticholinergics (benztropine IV/IM) — rapid relief | | **Akathisia** | Days to weeks | D₂ blockade in limbic regions | β-blockers, benzodiazepines | | **Parkinsonism** | Days to weeks | Nigrostriatal D₂ blockade | Anticholinergics, amantadine | | **Tardive dyskinesia** | Months to years | Denervation supersensitivity, D₂ upregulation | Prevention key; late recognition | ### Tardive Dyskinesia: Risk Factors **High-Yield:** Tardive dyskinesia risk correlates with: - **Duration of exposure** (cumulative risk ~5% per year) - **Total cumulative dose** - **Age** (higher risk in elderly) - **Female sex** - **Presence of mood disorder** Option 1 is **TRUE** — both duration and dose are independent risk factors. ### Neuroleptic Malignant Syndrome (NMS) **Clinical Pearl:** NMS is a rare but life-threatening emergency with: - **Mortality:** 5–10% if untreated; <1% with early recognition and ICU management - **Classic tetrad:** Hyperthermia, rigidity, altered mental status, autonomic instability - **Pathophysiology:** Acute D₂ blockade in hypothalamus and basal ganglia - **Management:** Immediate drug discontinuation, supportive care, dantrolene or bromocriptine Option 2 is **TRUE** — NMS mortality is indeed up to 10% if untreated. ### Acute Dystonia: Rapid Response to Anticholinergics **Mnemonic:** ABCD of acute dystonia — **A**cute onset, **B**enztropine (anticholinergic), **C**omplete relief, **D**ose-dependent. Benztropine 1–2 mg IV/IM produces relief within **5–15 minutes** because acute dystonia results from relative cholinergic excess in the basal ganglia following acute D₂ blockade. Option 3 is **TRUE** — anticholinergics provide rapid, dramatic relief. ### Metabolic Side Effects: Typical vs. Atypical Antipsychotics **Warning:** This is the key distinction. **Atypical antipsychotics** (olanzapine, clozapine, risperidone) are associated with **greater weight gain, hyperglycemia, and dyslipidemia** than typical antipsychotics. | Antipsychotic Class | Weight Gain Risk | Metabolic Syndrome Risk | |---|---|---| | **Typical** (haloperidol, chlorpromazine) | Low to moderate | Low | | **Atypical** (olanzapine, clozapine) | **High** | **High** | | **Atypical** (aripiprazole, ziprasidone) | Low | Low | **High-Yield:** Option 4 is **FALSE** — the reverse is true. Atypical antipsychotics carry a **greater metabolic burden** than typical antipsychotics, making this the correct answer for an "EXCEPT" question.