The Food and Drug Administration (FDA) has approved Zimhi™ (naloxone hydrochloride) injection for the emergency treatment of known or suspected opioid overdose, as manifested by respiratory and/or central nervous system depression.

Zimhi is an opioid antagonist that delivers 5mg/0.5mL naloxone hydrochloride solution in a single-dose, prefilled syringe for intramuscular or subcutaneous use. The product is intended for immediate administration as emergency therapy in settings where opioids may be present.

The application was submitted under the FDA’s 505(b)(2) approval pathway which relied, in part, on the safety and efficacy of injectable naloxone hydrochloride to support approval. The approval was also supported by pharmacokinetic data that established the safety and efficacy of the product.

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In a pharmacokinetic study of 14 healthy adults, a single intramuscular injection of Zimhi 5mg provided significantly higher Cmax and AUC compared with a single intramuscular injection of naloxone HCl 2mg.

“We are very excited by this approval and are working with our commercial partner, US WorldMeds, to make this much-needed, lifesaving product readily available to the market,” said Dr Dennis J. Carlo, President and CEO of Adamis. “Zimhi provides the highest systemic levels of naloxone compared to any of the nasal or intramuscular products currently available.”

Zimhi is expected to be available in the first quarter of 2022.


  1. FDA approves naloxone injection to counteract opioid overdoses. News release. US Food and Drug Administration. Accessed October 18, 2021.
  2. Adamis receives FDA approval for Zimhi. News release. Adamis Pharmaceuticals Corporation. Accessed October 18, 2021.
  3. Zimhi. Package insert. COMPANY; 2021. Accessed September 3, 2021.

This article originally appeared on MPR