According to the Centers for Disease Control and Prevention, 70,630 Americans died from a drug overdose in 2019.1 The Food and Drug Administration (FDA) has now approved another injectable form of naloxone in an effort to prevent deaths from opioids. Zimhi is a single-dose prefilled syringe containing 5 mg/0.5 mL of naloxone administered subcutaneously or intramuscularly.

All naloxone products are opioid antagonists and reverse the effects of opioids. Patients given Zimhi or any other naloxone product still need to be taken to the ED because the drug's half-life is shorter than the half-life of many opioids, and a recurrence of respiratory and central nervous system depression from the overdose is possible. Reversal of respiratory depression may be incomplete if the drug that induced the overdose was a partial agonist or mixed agonist/antagonist. For patients who are opioid dependent, the administration of Zimhi or another naloxone product may induce severe opioid withdrawal. If the drug is given postoperatively, a too-rapid administration may produce cardiovascular effects.

Several other naloxone products are available. The FDA previously approved an injectable 2-mg/mL dose of naloxone under the trade name Narcan. Injectable forms of generic naloxone are frequently available in hospitals in 0.4 mg/mL vials. There are also naloxone nasal sprays. One is 4 mg per spray and one, under the trade name Kloxxado, provides 8 mg per spray. A 2-mg spray is no longer marketed, but this is not because of safety or efficacy concerns.

According to the FDA, Zimhi was approved through the 505(b)(2) approval pathway under the Food, Drug, and Cosmetic Act. A new drug application submitted via this pathway may rely on the FDA's finding that a previously approved drug is safe and effective or on published literature to support the safety and/or effectiveness of the proposed product if such reliance is scientifically justified. In this case, the manufacturer submitted a 505(b)(2) application that relied, in part, on the FDA's finding of safety and effectiveness for Narcan.

Nurses should educate patients receiving opioids and their families on how to use Zimhi or other prescribed naloxone products. Because the needle is exposed after use until the safety guard is activated, it is important to teach caregivers how to avoid a needlestick injury from the Zimhi syringe.

For complete prescribing information for Zimhi, go to http://www.accessdata.fda.gov/drugsatfda_docs/label/2021/212854s000lbl.pdf.

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