By William Elliott, MD, FACP, and James Chan, PharmD, PhD
Dr. Elliott is Medical Director, Pharmacy, Northern California Kaiser Permanente, Assistant Clinical Professor of Medicine, University of California, San Francisco. Dr. Chan is Pharmacy Quality and Outcomes Manager, Kaiser Permanente, Oakland, CA
Drs. Elliott and Chan report no financial relationships relevant to this field of study.
The FDA has approved naloxone in the form of a nasal spray as a life-saving medication to reverse the effects of an opioid overdose. Naloxone has been available previously in an injectable form administered by syringe or auto-injector. The nasal spray was granted fast-track designation and priority review by the FDA. It is marketed by Adapt Pharma, Inc. as Narcan.
INDICATIONS
Naloxone spray is indicated as an opioid antagonist for the emergency treatment of known or suspected opioid overdose as manifested by respiratory and/or central nervous system depression.1
DOSAGE
Naloxone nasal spray is dosed as a single spray into one nostril. Additional doses may be given using a new spray with each dose. If there is no response or if the patient relapses, additional doses may be given every 2 to 3 minutes until emergency medical assistances arrives.1 Each spray delivers 4 mg (0.1 mL) of naloxone hydrochloride.
POTENTIAL ADVANTAGES
The nasal spray provides an easier-to-administer form of naloxone but still delivers the drug as quickly and effectively as an injection.
POTENTIAL DISADVANTAGES
Naloxone has limited activity against partial agonists or mixed agonist/antagonists (e.g., buprenorphine, pentazocine). Larger and repeat doses may be required.1 Naloxone may precipitate opioid withdrawal in patients who are opioid-dependent. Altered nasal physiology or anatomy may affect the absorption of naloxone.2
COMMENTS
The approval of naloxone nasal spray was based on relative bioavailability to naloxone administrated intramuscularly. The relative bioavailability is approximately 47%. However, the nasal dose is 10 times higher (4 mg vs 0.4 mg).1 This provides a peak plasma concentration of 4.8 ng/mL compared to 0.88 ng/mL for the injectable form. The median (minimum, maximum) time to peak concentration is 0.5 hr (0.17, 1.00) for the nasal spray and 0.18 (0.08, 2.05) for IM administration.
CLINICAL IMPLICATIONS
Opioid overdose is a worldwide public health crisis. Naloxone is the drug of choice to reverse the respiratory and central nervous system depression caused by overdose. Naloxone nasal spray is the first available, non-injectable form of naloxone. Many first responders and primary caregivers felt that the nasal spray is easier to administer. Therefore, the nasal spray provides an important dosage form for the emergency reversal of opioid overdose, which may save lives. The wholesale cost is $62.50 per unit (spray).
REFERENCES
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Narcan Prescribing Information. Adapt Pharma, Inc. November 2015.
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Wermeling DP. A response to the opioid overdose epidemic: Naloxone nasal spray. Drug Deliv Transl Res 2013;3:63-74.
