Comprehensive Study Notes on Typical Antipsychotics

Overview of Typical Antipsychotics

• Classification: Antipsychotics are categorized into two primary types: typical and atypical.

• Terminology: Typical antipsychotics are also referred to as first-generation antipsychotics because they are the older class of these medications.

• Indications: Typical antipsychotics are used for the following clinical purposes:

  • Treatment of acute psychosis.

  • Management of psychotic disorders, specifically schizophrenia.

• Clinical Efficacy in Schizophrenia:

  • Positive Symptoms: Typical antipsychotics are effective in treating positive symptoms (e.g., hallucinations, delusions).

  • Negative Symptoms: They are not effective in treating the negative symptoms of schizophrenia (e.g., social withdrawal, lack of motivation).

Mechanism of Action

• The Dopamine Hypothesis: Psychosis and psychotic disorders are believed to be caused by an increased amount of the neurotransmitter dopamine within the brain.

• Dopamine Receptors: There are two main types of dopamine receptors in the brain:

  • Type One ($D_1$).

  • Type Two ($D_2$).

  • Both types include various subtypes.

• Pharmacodynamics: Typical antipsychotics work by antagonizing postsynaptic dopamine two ($D_2$) receptor sites.

  • This mechanism blocks dopamine transmission.

  • It decreases the total amount of dopamine activity in the brain, thereby eliminating or reducing the symptoms of psychosis.

Examples and Administration Routes

• Specific Medications: Representative examples of typical antipsychotics include:

  • Haloperidol

  • Chlorpromazine

  • Thioridazine

  • Flupentazole

• Routes of Administration:

  • Oral: Typical antipsychotics can be taken by mouth.

  • Intramuscular (IM) Injection: Some forms can be administered as an injection.

• Depot Antipsychotics:

  • Definition: A depot is a long-acting, sustained-release formulation of an antipsychotic given as an intramuscular injection.

  • Frequency: These are typically administered every $2$ or $4$ weeks (fortnightly or monthly).

  • Indications for Depot Use:

  • Prescribed for individuals on a treatment order to ensure they receive their medication.

  • Chosen by patients who prefer not to take daily oral medication to improve adherence.

• Pharmacokinetic and Pharmacodynamic Considerations for Depots:

  • Absorption, distribution, metabolism, and elimination ($ADME$) are significantly slower compared to the oral route.

  • Clinical Implication: Adverse effects will take a longer time to appear and a correspondingly longer time to resolve once the medication is stopped.

Ethical and Clinical Nursing Considerations

• Medication Administration Ethics: Nurses must recognize that IM injections are invasive and potentially traumatic, especially when administered without consent under a treatment order.

• Standards of Care:

  • Uphold dignity, respect, and privacy at all times.

  • Prioritize clear communication and patient education.

Serious Adverse Effects: Extrapyramidal Effects

• Cause: Typical antipsychotics have additional effects at the synapse that result in movement disorders, collectively known as extrapyramidal effects ($EPSEs$).

• Types of Extrapyramidal Effects:

  • Tardive Dyskinesia: Characterized by involuntary muscle movements, such as lip smacking or rolling of the tongue.

  • Akathisia: Characterized by internal restlessness and physical agitation.

  • Acute Dystonias: Sudden and often painful muscle spasms of the head, neck, and torso.

  • Parkinsonism: The presentation of symptoms similar to Parkinson's disease (e.g., tremors, rigidity).

• Impact on Treatment: These effects significantly impair quality of life and are poorly tolerated, often leading to non-adherence (patients choosing to stop medication against medical advice).

Life-Threatening Complication: Neuroleptic Malignant Syndrome (NMS)

• Nature: NMS is a life-threatening medical emergency if not identified and treated promptly.

• Symptom Clusters for Identification: To assist in learning, the signs and symptoms are categorized into four areas:

  1. Hyperthermia (High fever).

  2. Mental Status Changes.

  3. Muscle Rigidity.

  4. Autonomic Instability.

• Nursing Management of NMS:

  • Frequent assessment for signs and symptoms.

  • Escalation and initiation of immediate care upon detection.

  • Cessation of the antipsychotic medication in consultation with a medical officer.

  • Provision of supportive therapy.

  • Close monitoring of the patient.

  • Arrangement of transfer to an Intensive Care Unit ($ICU$) if the patient is severely unwell.

Other Adverse Effects

• Less Severe Side Effects:

  • Sedation.

  • Photosensitivity.

  • Weight gain.

  • Anticholinergic effects (e.g., dry mouth, blurred vision).

Comprehensive Patient Education

• Safety Education: Patients must be taught the signs and symptoms of extrapyramidal effects and NMS so they can seek medical help early to prevent deterioration.

• Medication Adherence Instructions:

  • Take medication exactly as prescribed.

  • Seek medical advice if side effects become intolerable or concerning.

  • Warning: Do not suddenly stop taking the medication.

  • Continue the medication regimen even if the symptoms of psychosis have improved and the person feels better.