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Antidepressant Toxicity Nursing Guide

Content reviewed by Ann Dietrich, MD, FAAP, FACEP.

Antidepressant Toxicity Etiology and epidemiology 

Antidepressant toxicity arises from the overdose or adverse reaction to medications prescribed to treat depression, a common yet serious mental health condition. Antidepressants work by altering brain chemicals known as neurotransmitters, such as serotonin, norepinephrine, and dopamine. The three main classes of antidepressants include: 

  • Selective serotonin reuptake inhibitors (SSRIs): These are the most prescribed antidepressants and are generally safer than other classes. SSRIs increase serotonin levels in the brain and are used for depression, anxiety disorders, obsessive-compulsive disorder (OCD), panic disorders, and eating disorders. Examples include: 
    • Citalopram (Celexa®) 
    • Escitalopram (Lexapro®) 
    • Paroxetine (Paxil®) 
    • Sertraline (Zoloft®) 
  • Tricyclic antidepressants (TCAs): Older antidepressants that inhibit the reuptake of norepinephrine and serotonin. They’re less commonly used today due to the availability of safer alternatives. Examples include: 
    • Amitriptyline (Elavil®) 
    • Doxepin (Silenor®) 
    • Clomipramine (Anafranil®) 
    • Imipramine (Tofranil®) 
  • Monoamine oxidase inhibitors (MAOIs): These antidepressants work by inhibiting the breakdown of neurotransmitters like norepinephrine, dopamine, and serotonin. MAOIs require dietary restrictions and are less commonly prescribed due to the risk of severe interactions. Examples include: 
    • Isocarboxazid (Marplan®) 
    • Phenelzine (Nardil®) 

Incidence 

  • SSRI toxicity: Relatively common due to the widespread use of SSRIs, with over 50,000 overdose cases reported in 2016, including 102 fatalities (Bruggeman & O’Day, 2021). 
  • TCA toxicity: Less common but associated with a higher hospitalization rate compared to SSRIs (Khalid & Waseem, 2021). 
  • MAOI toxicity: Rare, with fewer than 300 cases reported in 2015, but potentially fatal due to severe interactions with certain foods and medications (Garcia & Santos, 2021). 

Antidepressant Toxicity Diagnosis 

Diagnosing antidepressant toxicity involves taking a detailed medical history, assessing the type and amount of antidepressant ingested, and evaluating for specific symptoms: 

  • History intake: 
    • Specific antidepressant and dose ingested 
    • Time of ingestion 
    • Co-ingestion of other substances, including alcohol 
    • Medical and mental health history 
    • Current medications, including herbal supplements 
  • Diagnostic criteria: 
    • Serotonin syndrome (SS): Diagnosed using the Hunter Serotonin Toxicity criteria, which includes symptoms like spontaneous clonus, inducible clonus with agitation or diaphoresis, and ocular clonus with hypertonicity and fever. 
    • TCA toxicity: Symptoms typically appear within two hours and include mental status changes, tachycardia, hypotension, and mydriasis. 
    • MAOI toxicity: Symptoms range from mild (agitation) to severe (hyperthermia, seizures, cardiorespiratory depression). 
  • Diagnostic tests: 
    • Comprehensive metabolic panel 
    • Complete blood count (CBC) 
    • Liver function tests 
    • Serum levels and urine toxicology screen 

Antidepressant Toxicity Management 

Management of antidepressant toxicity is tailored to the specific medication ingested and its severity: 

  • Airway, breathing, circulation (ABCs): Immediate management focuses on maintaining vital functions. 
  • Medication discontinuation: Cease the offending drug immediately. 
  • Cardiac monitoring: Regular monitoring of heart rate and rhythm. 
  • Behavioral control: Manage agitation and restlessness, often with sedatives. 
  • Fever management: Use antipyretics and cooling measures. 
  • Hydration: Maintain adequate fluid intake to prevent dehydration. 
  • Quiet environment: Reduce stimuli to help manage symptoms. 
  • Suicide precautions: Initiate if the overdose was intentional. 
  • Psychological evaluation: Necessary for individuals with intentional overdoses. 

Antidepressant Toxicity Nursing Care Plan

Nursing considerations 

Assessment 

Monitor for the following signs and symptoms: 

  • Altered mental status: Confusion, delirium, or decreased consciousness 
  • Autonomic instability: Diaphoresis, tachycardia, and hyperthermia 
  • Neuromuscular abnormalities: Myoclonus, rigidity, and ataxia 
  • Gastrointestinal symptoms: Nausea, vomiting, and decreased bowel sounds 

Nursing diagnoses 

  • Ineffective airway clearance: Related to neuromuscular impairment and risk of aspiration. 
  • Situational low self-esteem: Related to the stigma of mental illness and the effects of toxicity. 
  • Deficient knowledge: Related to a lack of understanding about the risks of antidepressants and overdose. 

Interventions 

  • Monitor respiratory status: Ensure airway patency and administer oxygen as needed. 
  • Institute seizure precautions 
  • Cardiac monitoring: Watch for arrhythmias and manage accordingly. 
  • Monitor neurological status: Regular assessment for changes in mental state or development of seizures. 
  • Fall precautions: Implement to prevent injury due to altered mental status or motor function. 
  • Provide emotional support: Offer reassurance and support to the individual and their family. 
  • Self-harm protocol: Initiate if there is a risk of further self-harm. 

Expected outcomes 

  • Maintains patent airway: No airway obstruction or respiratory compromise. 
  • Verbalizes increased self-esteem: Positive self-expression and decreased feelings of helplessness. 
  • Demonstrates effective coping: Uses appropriate coping mechanisms for stress and anxiety. 
  • Maintains safety: No falls or injuries during hospitalization. 
  • Expresses fears and anxieties: Open communication about feelings and concerns. 

Individual/caregiver education 

  • Understanding condition and treatment: Educate on the condition, treatment plan, and expected outcomes. 
  • Recognizing toxicity symptoms: Teach the signs of antidepressant toxicity and the importance of seeking immediate medical care. 
  • Medication safety: Discuss the risks of overdose and the importance of adhering to prescribed dosages. 
  • Follow-up care: Encourage regular follow-ups with a healthcare provider and psychiatric evaluation if necessary. 
  • Emergency contact: Advise on when to contact healthcare providers, particularly if symptoms worsen or suicidal thoughts occur. 

ICD-10 code for antidepressant toxicity 

  • T43.205A — Adverse effect of unspecified antidepressants, initial encounter 

FAQs

Additional Information

Content Release Date 

4/1/2022

Content Expiration

12/31/2028

References 

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