Skip to main content

Zimhi Dosage

Generic name: NALOXONE HYDROCHLORIDE 5mg in 0.5mL
Dosage form: injection, solution
Drug class: Antidotes

Medically reviewed by Last updated on Sep 29, 2022.

Important Administration Instructions

ZIMHI is for intramuscular and subcutaneous use only.

Because treatment of known or suspected opioid overdose must be performed by someone other than the patient, instruct the prescription recipient to inform those around them about the presence of ZIMHI and the Instructions for Use.

ZIMHI is intended to be administered by individuals 12 years of age or older. Younger individuals or those with limited hand strength may find the device difficult to use.

ZIMHI is light sensitive. Store ZIMHI in the outer case provided to protect it from light.

Prior to a medical emergency (during storage), periodically visually inspect ZIMHI™ through the viewing window on the device. If the solution is discolored yellow or brown color, cloudy, or contains particles, replace ZIMHI™ with a new one [see How Supplied/Storage and Handling (16.2)].

Do not attempt to reuse ZIMHI. Each ZIMHI contains a single dose of naloxone hydrochloride for single-dose injection.


Instruct the patient or caregiver to read the Instructions for Use at the time they receive a prescription for ZIMHI™. Emphasize the following instructions to the patient or caregiver:

  • Seek emergency medical care immediately after use. Because the duration of action of most opioids exceeds that of naloxone hydrochloride and the suspected opioid overdose may occur outside of supervised medical settings, seek immediate emergency medical assistance, keep the patient under continued surveillance until emergency personnel arrive, and administer repeated doses of ZIMHI as necessary. Always seek emergency medical assistance in the event of a suspected potentially life-threatening opioid emergency after administration of the first dose of ZIMHI.
  • Additional doses of ZIMHI may be required until emergency medical assistance becomes available [see Dosage and Administration (2.2)].
  • Administer ZIMHI according to the Instructions for Use and the printed instructions on the device label:
    Place the patient in the supine position.
    Inject ZIMHI intramuscularly or subcutaneously into the anterolateral aspect of the thigh with the needle facing downwards. Inject through clothing if necessary [see Instructions for Use].
    Embed the needle completely before transferring the thumb to the syringe plunger.
    Immediately after injection, using one hand with fingers behind the needle, slide the safety guard over the needle. Do not use two hands to activate the safety guard.
    Never put thumb, fingers, or hand over the exposed needle. Failure to follow these instructions may result in a needlestick injury. If an accidental needlestick occurs, get medical help immediately [see Warnings and Precautions (5.4)].
    Do NOT attempt to re-cap the needle with the needle cap once it has been removed [see Warnings and Precautions (5.4)].
    Place the patient in the lateral recumbent position (recovery position).
    ZIMHI must be used and/or properly disposed of as described below once the protective cap covering the needle is removed.
    Put the used syringe into the blue case, close the case, and give your used ZIMHI syringe to the healthcare provider for inspection and proper disposal.
    Tell the healthcare provider that you have received or administered an injection of naloxone HCl. Show the healthcare provider where the injection was administered.

Dosing Information

Initial Dosing

Administer the initial dose of ZIMHI™ to adult or pediatric patients intramuscularly or subcutaneously into the anterolateral aspect of the thigh, through clothing if necessary, and seek emergency medical assistance. Administer ZIMHI™ as quickly as possible because prolonged respiratory depression may result in damage to the central nervous system or death.

Repeat Dosing

The requirement for repeat doses of ZIMHI depends upon the amount, type, and route of administration of the opioid being antagonized.

If the desired response is not obtained after 2 or 3 minutes, an additional dose of ZIMHI may be administered. If there is still no response and additional doses are available, additional doses of ZIMHI may be administered every 2 to 3 minutes until emergency medical assistance arrives.

Additional supportive and/or resuscitative measures may be helpful while awaiting emergency medical assistance.

If the patient responds to ZIMHI and relapses back into respiratory depression before emergency assistance arrives, administer an additional dose of ZIMHI and continue surveillance of the patient after administering an additional dose.

Reversal of respiratory depression by partial agonists or mixed agonist/antagonists, such as buprenorphine and pentazocine, may be incomplete and may require higher doses of naloxone hydrochloride or repeated administration of ZIMHI.

Dosing in Adults and Pediatric Patients

Instruct patients or their caregivers to administer ZIMHI according to the Instructions for Use, intramuscularly or subcutaneously.

Dosing in Pediatric Patients under Age One Year

In pediatric patients under the age of one year, the caregiver should pinch the thigh muscle while administering ZIMHI. Carefully observe the administration site for signs of infection following resolution of the opioid emergency.

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.