Procedural Sedation and Analgesia

Rarely, one may need to administer reversal agents in the event that the patient has been deeply sedated to the state of general anesthesia.

Although most agents are rapidly metabolized, and no additional medication is necessary, the midazolam and fentanyl regimen could last for 20–30 minutes. Narcan is more commonly given for opioid overdose, and flumazenil is indicated for benzodiazepine overdose. Although naloxone (Narcan) is relatively benign (symptoms of withdrawal excluded), flumazenil can potentially be dangerous in patients dependent on benzodiazepines, and precipitate a refractory seizure.

NALOXONE

Naloxone is an opioid antagonist that competes directly with systemic narcotics. It binds all the opiate receptors, but appears to have a higher affinity for the mu receptor. Naloxone may be given through the endotracheal (ET) tube, IM, IV, IO, or subcutaneously. It is not recommended to administer Narcan via ET tube in newborn infants. Narcan is dosed at 0.4–2 mg IV for adults, and it is recommended to give smaller amounts for patients chronically on opioids in order to avoid overt withdrawal. Abrupt reversal in patients chronically administered narcotics may result in seizures, cardiac arrhythmias, pulmonary edema, or profound agitation. Age-appropriate dosing is as follows:

• Newborns: 0.1 mg/kg IV/IM

• Pediatric < 5 years or < 20 kg: 0.1 mg/kg IV/IM/IO/SQ

• Pediatric > 5 years or > 20 kg: 2 mg IV/IM/IO/SQ

FLUMAZENIL

Flumazenil directly competes for the benzodiazepine binding site on the GABA receptor effectively reversing some aspects of the CNS depression (ie, respiratory depression). It does not facilitate the metabolism of benzodiazepines, and resedation can occur once the flumazenil wears off. It is given IV, undergoes hepatic metabolism, and is excreted renally. The systemic half-life for adults is 40–70 minutes, and in pediatric patients it may range from 20 to 75 minutes. The initial dosing in adults is 0.2 mg IV over 30 seconds with additional doses of 0.3–0.5 mg given IV for a total maximum dose of 3 mg. Pediatric patients are dosed at 0.01 mg/kg up to 0.2 mg IV over 15 seconds. Repeat doses may be given in increments of 0.01 mg/kg up to a maximum dose of 0.05 mg/kg total or 1 mg total. Flumazenil can cause refractory seizures in patients on chronic benzodiazepines, or patients with cyclic antidepressant overdoses. Should a patient develop seizure activity following flumazenil administration, benzodiazepines are unlikely to work despite large doses for competitive binding. Alternative adjuncts to mitigate the seizures include propofol or barbiturates.