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Antipsychotics: Nursing Pharmacology

Notes

Notes

ANTIPSYCHOTICS
DRUG NAME
-idol; e.g., haloperidol (Haldol)
-azine; e.g., thioridazine

-idone; e.g., risperidone (Perseris, RisperDAL)
-apine; e.g., clozapine (Clozaril)

CLASS
Typical antipsychotics
(1st generation)
Atypical antipsychotics
(2nd generation)
MECHANISM OF ACTION
  • D2 blockade in the mesolimbic pathway
  • D2 blockade in the mesolimbic pathway
  • 5-HT2A blockade
INDICATIONS
  • Schizophrenia
  • Psychosis
  • Acute mania
  • Delirium
  • Bipolar disorders
  • Obsessive-compulsive disorders
ROUTE(S) OF ADMINISTRATION
  • PO
  • IM
  • IV
  • SUBQ (risperidone)
  • Sublingual, topical (asenapine)
SIDE EFFECTS
  • Galactorrhea
  • Extrapyramidal side effects
    • Dystonia (hours–days)
    • Akathisia, pseudoparkinsonism (days–month)
    • Tardive dyskinesia (months–years)
  • Neuroleptic malignant syndrome (typical > atypical)
  • Anticholinergic side effects 
    • Dry mouth, blurred vision, urinary retention, constipation
  • Orthostatic hypotension
  • QT prolongation
  • Sedation (atypical > typical)
  • Metabolic syndrome (atypical)
CONTRAINDICATIONS AND CAUTIONS
  • QT prolongation
  • CNA depression
  • Alcohol
  • Boxed warning (all antipsychotics): increased risk of death in elderly clients with dementia-related psychosis
  • Clozapine: black box warning for severe neutropenia, seizures, fatal myocarditis, bradycardia, & cardiac arrest
NURSING CONSIDERATIONS: ANTIPSYCHOTICS
DRUG NAME-idol; e.g., haloperidol (Haldol)
-azine; e.g., thioridazine

-idone; e.g., risperidone (Perseris, RisperDAL)
-apine; e.g., clozapine (Clozaril)

ASSESSMENTS AND MONITORING
  • Mental and behavioral status
  • LOC
  • Weight
  • Vital signs
    • Assess for orthostatic hypotension
  • Laboratory: CBC, electrolytes, glucose, lipid profile, hepatic and renal function
  • Current medications
  • Side effects
    • Report adverse side effects to health care provider; intervene as ordered
CLIENT EDUCATION
  • Teach clients to recognize and manage side effects
    • Sedation: avoid hazardous activities; take medication in evening
    • Orthostatic hypotension: make position changes slowly
    • Anticholinergic effects: sugar-free hard candy or chewing gum, and frequent drinks of water; increase dietary fiber, fluids, and physical activity
    • For some antipsychotics: regular monitoring of lipid profile and CBC; avoid infection; recognize symptoms of hyperglycemia
  • Promptly report report flu-like symptoms or other signs of infections such as: fever and sore throat; symptoms of hyperglycemia; possible extrapyramidal symptoms
Memory Anchors and Partner Content
Transcript

Antipsychotics are medications mainly used to treat schizophrenia and other psychotic disorders, such as psychosis, acute mania, delirium, bipolar disorders, and obsessive-compulsive disorders.

Antipsychotics are most often administered orally, but some can also be sublingual or transdermal, or injected intramuscularly, intravenously, or subcutaneously.

Once administered, they travel to the brain and block dopamine D2 receptors in the mesolimbic pathway, thereby helping alleviate some psychotic symptoms.

Now, there are two main groups of antipsychotics: the first generation or typical antipsychotics, and the second generation or atypical antipsychotics.

Typical antipsychotics can be further classified as high-potency or low-potency medications. High-potency antipsychotics include medications such as haloperidol, trifluoperazine, and fluphenazine.

These medications have a high affinity for dopamine receptors, meaning they require lower doses to achieve their therapeutic effect.

On the flip side, low-potency antipsychotics include medications such as thioridazine, chlorpromazine, and thiothixene.

These medications have less affinity for dopamine receptors, therefore they require larger doses to achieve the same therapeutic effect as high-potency antipsychotics.

On the other hand, second generation, or atypical antipsychotics, include medications such as clozapine, olanzapine, quetiapine, risperidone, and ziprasidone.

In addition to blocking dopamine D2 receptors, atypical antipsychotics also work by blocking serotonin 5-HT2A receptors in the mesocortical pathway.

Another atypical antipsychotic is asenapine, which is administered sublingually or transdermally, to prevent clients from “cheeking” their medication; that’s when a client pretends to swallow their medication, but instead keeps it hidden between the teeth and the cheek.

Now, antipsychotics are not selective to the dopamine receptors in the mesolimbic pathway, meaning that they can also block dopamine receptors in other parts of the brain.

In addition, dopamine normally inhibits prolactin release, so by blocking dopamine receptors, antipsychotics subsequently increase the secretion of prolactin, causing galactorrhea, or a milk-like nipple discharge.

On the flip side, the blockade of dopamine receptors in the nigrostriatal pathway results in extrapyramidal symptoms, which usually involve abnormal movements like dystonia, which can occur within a few hours to days of treatment, and includes muscle spasms of the tongue, face, neck, and back.

This side effect is also associated with oculogyric crisis, which is a spasm of the extraocular muscles, causing an upward and outward position of the eyes.

After a few days to a month, a client can develop akathisia, characterized by restlessness and an urge to move the limbs, as well as, pseudoparkinsonism, characterized by muscle rigidity, usually in the facial muscles, and symptoms, such as bradykinesia or slow movements, and tremors.

Finally, clients may develop tardive dyskinesia after several months or even years, characterized by constant involuntary, rhythmic movements.

This usually affects the perioral muscles causing the person to repeatedly smack, or purse their lips. Unlike the rest of extrapyramidal symptoms, which usually disappear once the medication is stopped, tardive dyskinesia can be irreversible, so it’s important to discontinue the medication at the first sign of tardive dyskinesia.

Now, the most dangerous extrapyramidal side effect is neuroleptic malignant syndrome or NMS for short, which typically starts days to weeks after starting the medications.

It’s characterized by confusion, muscle rigidity, agitation, hyperthermia, seizures, and even coma. Finally, it’s important to note that typical antipsychotics are more likely to cause extrapyramidal side effects compared to atypical antipsychotics.

Now, besides dopamine receptors, antipsychotics can also block other receptors. Other side effects caused by blockade of muscarinic receptors include anticholinergic side effects such as dry mouth, blurred vision, urinary retention, and constipation.

On the other hand, blockade of alpha-1 adrenergic receptors may cause orthostatic hypotension. Blockade of histamine receptors may result in sedation.

Sources
  1. "Mosby's 2021 Nursing Drug Reference" Mosby (2020)
  2. "Pharmacology 8th Edition: A Patient-Centered Nursing Process Approach" Elsevier Health Sciences (2014)
  3. "Focus on Nursing Pharmacology" LWW (2019)
  4. "Saunders Comprehensive Review for the NCLEX-RN Examination" Saunders (2019)
  5. "The effect of the medicine administration route on health-related quality of life: Results from a time trade-off survey in patients with bipolar disorder or schizophrenia in 2 Nordic countries" BMC (2016)