Major Toxidromes

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Major Toxidromes
Priya Mital, MD IMRP Ambi Morning Report 2007
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Selective Serotonin Reuptake Inhibitors (SSRI)
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SSRIs

• Fluoxetine (Prozac)
• Sertraline (Zoloft)
• Paroxetine (Paxil)
• Fluvoxamine (Luvox)
• Citalopram (Celexa)
• Escitalopram (Lexapro)

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Case Burden

• In 2004, 48,204 reported exposures to US poison
  centers with 103 fatalities
• Fatalities usually associated with coingestants
• Generally much safer than TCAs and MAOIs
• SNRIs greater risk of toxicity and mortality in
  overdose (e.g. cymbalta, effexor)

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Wide therapeutic window

• 30 x daily dose minor or no symptoms
• 50-75 x daily dose vomiting, mild CNS
• depression, tremor
• 150 X daily dose
• presence of co-ingestants
• - Usually fatal

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Features of SSRI overdose

• Neurotoxic Seizures (1-2) dose-dependent
• Cardiotoxic QTc prolongation, Torsades
  (citalopram)
• Hyponatremia (SIADH)
• Serotonin syndrome

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Important history

• Which drugs were ingested?
  
• - all coingestants (ethanol, BZD, TCA)
• - drug formulations (-SR)
• What amount was ingested?
• When were the drugs ingested?
• Accidental vs. intentional?

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ABCs overdose

• Airway
• Breathing
• Circulation
• Look for toxidromes
  (vitals, pupils, skin, mental status, bowel
  sounds)
• Look for serotonin syndrome

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Lab evaluation for SSRI overdose

• Fingerstick glucose
• Acetaminophen/salicylate levels
• Ethanol level
• EKG (QRS/QTc intervals)
• Serum bicarbonate

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Management

• Supportive care
• Single dose of activated charcoal (50gm,
  1mg/kg) within 1-2 hrs of ingestion
• BZD for seizures (lorazepam/diazepam)
• Wide QRS tachycardia NaHCO3 bolus/drip
• Observe for 6-24 hrs for serotonin syndrome

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Serotonin Syndrome

• Excess stimulation of 5-HT1A/2A receptors
• Can happen with therapeutic medication dose, drug
  interactions, intentional overdose
• Presentation 6-24 hrs
• Classic triad mental status changes
• autonomic hyperactivity
• neuromuscular abnormalities

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Diagnosis of Serotonin Syndrome

• Hunter criteria (84 sensitive, 97 specific)
• Spontaneous clonus
• Inducible clonus plus agitation/diaphoresis
• Ocular clonus plus agitation/diaphoresis
• Tremor and hyperreflexia
• Hypertonia
• Temperature gt 380C plus ocular/inducible clonus

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Labs(to monitor for complications only)

• CBC
• Chem7
• LFTs
• Coagulation profile (PT, INR, aPTT)
• CK, UA
• CXR, ABG
• Head CT, LP

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Management

• 5 principles
• d/c all serotonergic agents
• Supportive care (O2, IVF, monitor vitals)
• Sedation with BZD
• Serotonin antagonists (cyproheptadine)
• Need to resume use of causative agents

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Risk of serotonin syndrome

• Sertraline 20
• Paroxetine 18
• Fluvoxamine 17
• Citalopram 9
• Fluoxetine 1

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Our patient

• Ingested 60 pills of 50 mg sertraline
• Presented within 30 minutes of drug ingestion
• Got one dose of activated charcoal
• No major features of toxicity at presentation
• Observed for 6-8 hours
• EKG no QTc prolongation
• No signs of serotonin syndrome
• Transferred to psychiatric facility for control
  of depression and suicidal ideation