Signage is seen outside of FDA headquarters in White Oak, Maryland
Signage is seen outside of the Food and Drug Administration (FDA) headquarters in White Oak, Maryland, U.S., August 29, 2020. Reuters

Emergent BioSolutions Inc's over-the-counter version of opioid overdose reversing drug received unanimous support from U.S. Food and Drug Administration's panel of advisers, sending shares of the contract drugmaker up nearly 16% after market.

The vote puts the naloxone-based treatment Narcan on track to potentially become the first opioid overdose drug to be sold OTC nationwide. Naloxone rapidly reverses or blocks the effects of an overdose, restoring normal respiration.

While some experts believe an eventual approval by the U.S. health regulator could make an impact on the overdose crisis, others have cautioned against prescription-free use of naloxone, citing the need for professional oversight.

However, most panelists emphasized that OTC use of the nasal spray was safe and proposed ways to improve its labeling, to avoid using the drug wrong.

Panelist Brian Bateman said there was room for improving the labeling, "but I think the evidence we saw today provides clear indications that the drug can be used without direction of the healthcare provider."

Advisers suggested that all five steps of administering the drug should be printed only on the back panel instead of across the back and side panels of the drug's packaging, which has led to confusion among consumers about the order of the steps to be followed.

Other suggestions were around including a separate 'quick-start' user guide and including pictograms for easier identification of different parts of the spray.

"The current prescription version has a little paper flap that gives the instructions..which the proposed over-the-counter version won't have. It would just be very clear on the box about the steps to use (the drug) and so I think that would be helpful," said Scott Weiner, an emergency medicine physician at Brigham and Women's Hospital ahead of the panel meeting.

An approval for OTC Narcan could increase its availability and align the federal government's stance with that of various states that have provisions to offer the drug without prescriptions through a pharmacist.

In support of the favorable vote, the American Medical Association said it believes "greater access will occur when naloxone for overdose risk is just as easily accessible in a pharmacy, grocery store and other common locations as a decongestant for a stuffy nose."

The FDA, which usually follows the recommendations of its expert panel but is not obligated to do so, is expected to make its final decision by March 29 on prescription-free sale of Narcan.