Schizophrenia

Most common psychotic disorder with a lifetime worldwide prevalence of 1%

Increased risk of suicide (5–10%)

Marked by deterioration of function and self-care

Exacerbation of psychosis with abrupt discontinuation of medications

Pt being uncooperative, combative, or catatonic.

Increased morbidity and mortality due to poorly controlled coexisting systemic disease and increased incidence of alcohol and substance abuse.

Drug interactions and side effects:

• Cardiogenic side effects include hypotension, tachycardia, prolonged QT interval, VFIB, and torsades-de-pointes.

• EPS include muscle rigidity and laryngospasm.

• Use of metoclopramide may worsen schizophrenic symptoms.

Schizophrenia is a psychiatric disorder that may be characterized by thought disorders, hallucinations, and fixed false beliefs.

Antipsychotic medications are the mainstay treatment for schizophrenia.

Antipsychotics have anticholinergic effects (dry mouth, blurry vision, urinary retention, constipation, tachycardia), histamine antagonism (sedation), and α1 antagonism (orthostatic hypotension).

First-generation antipsychotics have strong dopamine antagonism leading to EPS, such as tardive dyskinesia.

Second-generation or atypical antipsychotics have serotonin antagonism and less dopamine antagonism leading to less EPS.

EPS can be treated with anticholinergics such as benztropine 2 mg or diphenhydramine 50–100 mg.

NMS is a rare but potentially fatal syndrome occurring after an increase in dosage of antipsychotic medications or abrupt D/C of dopamine agonist. The syndrome is marked by muscle rigidity, hyperthermia, altered consciousness, and autonomic instability. It is clinically similar to malignant hyperthermia and may be related to dopamine blockade.

Autonomic instability presents as labile blood pressure, tachycardia, diaphoresis, incontinence, and flushing.

Treatment of NMS includes hydration and cooling measures, IV dantrolene, and dopamine agonists such as bromocriptine.

• Bromocriptine reduces mortality by 50% and is only available orally; thus NGT may be required.

• Dantrolene is a skeletal muscle relaxant and will reduce heat production.

• Benzodiazepines may also be used to alleviate catatonic symptoms.

Avoid dopamine antagonists, such as metoclopramide, if NMS is suspected.

Functional hyperactivity of dopamine transmission may play a role.

Genetic and environmental factors are unclear and controversial.