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Adams chap 16 Antipsychotics (1)

Drugs for Psychosis

Overview

  • Psychosis involves losing contact with reality, leading to disorganized thoughts, incoherence, and distortion of reality.

  • Symptoms can include delusions, hallucinations, catatonia, and aggressive or violent behavior.

Key Drugs to Know

  • Chlorpromazine

  • Fluphenazine

  • Clozapine

  • Haloperidol

  • Ziprasidone

  • Dantrolene

Schizophrenia

Characteristics

  • A chronic psychotic disorder that usually manifests in adolescence or early adulthood.

  • Symptoms categorized into three types: cognitive, positive, and negative.

Symptoms

  • Cognitive Symptoms:

    • Disorganized thought

    • Memory difficulty

    • Decreased ability to focus attention

  • Positive Symptoms:

    • Exaggerated behavior (such as agitation)

    • Incoherent speech

    • Hallucinations

    • Delusions and paranoia

  • Negative Symptoms:

    • Decreased/loss of function and motivation

    • Social withdrawal and poor self-care

    • Poverty of speech content

    • Usually more chronic and persistent.

Pathophysiology

  • Symptoms believed to stem from an imbalance in dopamine in the brain.

  • Antipsychotics work by blocking dopamine receptors intended to improve thought processes and behavior.

  • Some antipsychotics may also block the vomiting center in the brain.

Extrapyramidal Symptoms (EPS)

Overview

  • Result from blocking dopamine and may start 5-30 days after the first dose.

  • Symptoms include:

    • Pseudo-parkinsonism (tremors, rigidity, shuffling gait, bradykinesia)

    • "Frozen" appearance.

Side Effects of Antipsychotics

Early Side Effects

  • Acute Dystonia:

    • Muscle spasms affecting face, neck, tongue, back.

    • Features include facial grimace, up gazing eyes, laryngeal spasm.

    • Treated with antiparkinsonian medications like benztropine.

  • Akathisia:

    • Symptoms include restlessness and uncontrollable pacing.

    • Treatment options include benzodiazepines or beta blockers.

Late Side Effects

  • Tardive Dyskinesia:

    • Develops after one year of treatment.

    • Symptoms include protrusion and rolling of the tongue, lip smacking, and involuntary movements.

    • Most severe in the elderly and is NOT reversible; requires stopping the drug.

    • Treatment options include benzodiazepines, beta blockers, calcium channel blockers, or Vitamin E.

Neuroleptic Malignant Syndrome

  • Rare but life-threatening condition characterized by:

    • Muscle rigidity, sudden high fever, altered mental state.

    • Other symptoms include tachycardia, unstable BP, seizures, respiratory and renal failure, coma.

  • Treatment involves stopping the medication, supporting vital signs, and administering benzodiazepines and muscle relaxants like dantrolene.

Types of Antipsychotics

Typical Antipsychotics (Older Drugs)

  • Phenothiazines:

    • Block norepinephrine, often accompanied by sedation and hypotensive effects.

  • Non-phenothiazines:

    • Primarily block dopamine.

Atypical Antipsychotics (Newer Drugs)

  • Target both positive and negative symptoms with fewer side effects.

  • Often prescribed as first-line therapy for conditions like schizophrenia, Tourette's syndrome, and Huntington’s chorea.

Specific Medications

Chlorpromazine

  • Notable for strong sedative effects and used in various conditions, including intractable hiccups.

Haloperidol

  • Very potent antipsychotic used in treating psychoses and schizophrenia.

  • Common side effects include sedation, extrapyramidal symptoms, and orthostatic hypotension.

  • Long-acting formulations are available (Haldol decanoate).

Care Implications

  • Monitor for unique side effects, such as pink/red urine.

  • Antipsychotic therapy can take 7-8 weeks to show full effects.

  • Strongly protein-bound; use with caution in patients with liver disease.

  • Non-adherence is frequent; consider alternative administration methods such as parenteral forms.

Adherence to Therapy

  • Non-adherence is common; educational and supportive approaches are essential.

  • Involve family, provide professional yet empathetic support, and assure that medication use does not lead to addiction.

Drug Interactions and Toxicity

Important Considerations

  • Sedatives: May cause increased sedation and risk of falls.

  • Levodopa/carbidopa: Can counteract the effects of antipsychotics.

  • Toxicity: Generally safe with rare fatal overdoses; however, discontinuation should be monitored to avoid withdrawal symptoms.