Chapter 56. Antidotes

• Indication: reversal of nondepolarizing muscle relaxants for patients with residual neuromuscular block (TOF ratio <0.9)
• Mechanism of action: reversibly inhibits acetylcholinesterase and thus potentiates the nicotinic and muscarinic effects of acetylcholine
• Only use if ≥1 response on TOF
• Dose: 50–70 μg/kg
• Glycopyrrolate 10–15 μg/kg associated to prevent adverse parasympathetic side effects of neostigmine (muscarinic effects: bradycardia, bronchospasm, increased secretions, etc)
• Atropine possible too (20 μg/kg), but more tachycardia and less antisialagogue action than glycopyrrolate. Also, atropine crosses the BBB and can cause CNS side effects
• Onset time: 10 minutes
• Goal: TOF ratio >0.9
• Contraindications: unstable asthma, Parkinson disease, deep NMB with no response on TOF, succinylcholine
• In children, edrophonium 500 μg/kg paired with atropine 20 μg/kg is often used instead of neostigmine. The onset time is shorter, although the difference is probably not clinically significant

• Currently not approved by the FDA, not available in the United States
• Indication: reversal of NMB by selective biding of nondepolarizing steroidal muscle relaxants (aminosteroids)—rocuronium, vecuronium, and pancuronium
• Dose: reversal of rocuronium or vecuronium:
  • With 4/4 on TOF: 2 mg/kg (onset time: 1 minute)
  • With 2/4 on TOF: 4 mg/kg (onset time: 2 minutes)
  • No response on TOF: 16 mg/kg (onset time: 2 minutes)

• Morphine antagonist (mu-opioid receptor competitive antagonist)
• Indicated for:
  • Opioid overdose
  • Treatment for side effects of IV or neuraxial morphine: respiratory depression, CNS depression, urinary retention
• Contraindications: allergy, caution in patients at risk for myocardial ischemia because it can result in increased sympathetic activity
• Dose: one vial IV (400 μg in 1 mL) diluted in 9 mL normal saline, titration milliliter per milliliter until respiratory rate >12/min. Avoid giving more than needed because of severe pain, difficult to treat, and agitation
• Onset time: 1 minute, and effects may last up to 45 minutes (shorter than duration of action of most opioids)—risk of “remorphinization”
• Maintain by continuous infusion, adjusted to clinical response (e.g., two vials [800 μg] over 3 hours)

• Indicated for: reversal of sedative and hypnotic effects of benzodiazepines
• Contraindications: allergy to benzodiazepines, chronic treatment with benzodiazepines (withdrawal syndrome with risk of seizure), intoxication with medications that can cause seizures (e.g., tricyclic antidepressants), inability to monitor (duration of action of flumazenil is shorter than that of most benzodiazepines)
• Dose: bolus 0.3 mg, and then titration 0.2 mg/min (maximum 2 mg); maintain by IV infusion 0.1–0.4 mg/h

See Chapter 119.

• Indication: rescue for cardiac toxicity associated with local anesthetics, especially bupivacaine and ropivacaine—arrhythmia, severe hypotension, or asystole
• Contraindications of Intralipid administration for nutrition: severe disorders of fat metabolism such as severe liver damage, acute myocardial infarction, shock, dyslipidemia, hemostatic abnormalities, hypersensitivity to Intralipid; none of these contraindications apply when used for LA toxicity
• Recommended dose: 1.5 mL/kg of 20% Intralipid IV bolus (can be repeated once if persistent asystole) followed by a continuous infusion of 0.25 mL/(kg min) for 30 minutes (the rate of the infusion ...