NACCT Platform Abstracts 2012 - The American Academy of Clinical ...

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Effectiveness of low dose naloxone to reverse respiratory depression in opioid intoxication
Hong K Kim 1 , Lewis S Nelson 1
1 New York University School of Medicine, New York NY USA
Background: Although naloxone reverses the respiratory and CNS effects of opioids, care must be utilized to avoid
precipitating acute opioid withdrawal syndrome (OWS). The commonly recommended initial naloxone dose of 0.4 mg is
based on studies in a non-opioid-dependent population undergoing anesthetic reversal. However, in opioid-dependent
patients, this dose predictably results in acute withdrawal. Despite limited data demonstrating the efficacy of a lower dose of
naloxone, 0.04 mg is often recommended in medical toxicology and anesthesia texts as safe and effective. The objective of this
study was to evaluate the clinical effects of naloxone 0.04 mg (with titration) on the respiratory depression noted in ED patients
with acute opioid overdose.
Methods: A prospective observational study of the current ED practice of naloxone use in opioid intoxicated patients was
conducted. Thirty consecutive ED patients, 18 years and older, with clinical findings of opioid intoxication (e.g., history, CNS
depression, pinpoint pupils, RR < 8/ minute) requiring naloxone were included. The primary outcome was improved RR.
Secondary outcomes were end-tidal CO2 level (CO2), pulse oximetry (O2 sat) on room air, Richmond Agitation Sedation
Scale (RASS), and OWS.
Results: Preliminary results involving five ED patients are summarized in the table. All five patients experienced coma with
hypoventilation due to methadone use. On average, patients required two naloxone doses of 0.04 mg. One patient (patient D)
experienced acute OWS with a total naloxone dose of 0.08 mg.
Table
Patient A
Patient B
Patient C
Patient D
Patient E
Drug history Clinical findings Naloxone (mg) Clinical response
Methadone
Methadone
Benzodiazepine
Methadone
Methadone
Methadone
RR: 6/min
RASS: -4
O 2 sat: 87%
CO 2 : 50 mmHg
RR: 7/min
RASS: -4
O 2 sat: 95%
CO 2 : NR
RR: 6/min
RASS: -5
O 2 sat: 80%
CO 2 : NR
RR: NR
RASS: -5
O 2 sat: 40%
CO 2 : 60 mmHg
RR: 3/min
RASS: -4
O 2 sat: 92%
CO 2 : 55 mmHg
IV: 0.04 x 2
IV: 0.04 x 3
Infusion: 0.04 mg/hr
IV: 0.04
Infusion: 0.05 mg/hr
IV: 0.04 x 2
Infusion: 0.1 mg/hr
IV: 0.04 x 2
Infusion: 0.05 mg/hr
RR: 14/min
RASS: 2
O 2 sat: 95%
CO 2 : 42 mmHg
RR: 9/min
RASS: -1
O2 sat: 99%
CO 2 : NR
RR: 12/min
RASS: 0
O 2 sat: 92%
CO 2 : 29 mmHg
RR: 13/min
RASS: 2
O 2 sat: 99%
CO 2 : NR
OWS: vomitting
RR: 6/min
RASS: -2
O 2 sat: 94%
CO 2 : 50 mmHg
NR: not reported
Conclusion: A naloxone dose of 0.04 mg with appropriate dose titration can effectively reverse both respiratory and CNS
depression. A total dose of 0.08 mg may be required, but titration would limit the risk of acute OWS. Initial results indicate the
commonly recommended initial dose of 0.4 mg may be excessive.