Typical Antipsychotics and EPS

First-generation agents like haloperidol and chlorpromazine block dopamine receptors, effectively treating positive symptoms but causing extrapyramidal symptoms (EPS): acute dystonia (sudden muscle spasm, often laryngeal — a medical emergency treated with IM diphenhydramine or benztropine), akathisia (restlessness), pseudoparkinsonism (tremor, rigidity, shuffling gait), and tardive dyskinesia (involuntary lip-smacking, tongue movements) after long-term use, which may be irreversible. Assess regularly with the AIMS scale. Anticholinergic effects (dry mouth, constipation, urinary retention, blurred vision) are also common with these agents.

Atypical Antipsychotics and Metabolic Syndrome

Second-generation agents (olanzapine, risperidone, quetiapine, clozapine) have lower EPS risk but carry significant metabolic risk: weight gain, hyperglycemia, and dyslipidemia, requiring baseline and periodic monitoring of weight, fasting glucose, and lipid panels. Clozapine uniquely causes agranulocytosis, requiring weekly to biweekly absolute neutrophil count monitoring — a sore throat or fever in a clozapine patient demands immediate ANC testing before continuing the drug. Risperidone can still cause EPS at higher doses despite being atypical, a common NCLEX distractor.

Neuroleptic Malignant Syndrome

NMS is a rare but life-threatening emergency presenting with muscle rigidity, hyperthermia (often over 104°F), autonomic instability (fluctuating BP, tachycardia), and altered mental status, typically within the first two weeks of starting or increasing an antipsychotic dose. The priority action is to immediately stop the antipsychotic, provide supportive cooling and IV fluids, and administer dantrolene or bromocriptine as ordered. NMS is distinguished from serotonin syndrome by the presence of 'lead-pipe' rigidity and slower onset; both require prompt recognition to prevent rhabdomyolysis and renal failure.