> Western Medicines > Naloxone


Used for: Opioid overdose
Chinese name:

What is Naloxone for?

Naloxone belongs to a class of medications called opioid antagonists. It works by competing with opioid’s action site to reverse its effects. It can be used to treat acute opioid overdose.

How to use it?

Naloxone can be administered intravenously, intramuscularly or subcutaneously. The usual dose is 0.4-2 mg, and may repeat 2-3 minutes as needed, up to 10 mg.


After reversal, may need to re-administer dose(s) at a later interval (e.g. 20-60 minutes) depending on type or duration of opioid and monitor closely.


If no response is observed after 10 mg total, reconfirm the diagnosis of opioid toxicity.

What are the side effects of Naloxone?

Common side effects of Naloxone include injection site erythema, dizziness, flushing, and injection site pain and swelling.

Who should not take Naloxone?

People who are allergic to Naloxone or any component of the formulation.

Pharmacist Tips:

  • Talk to your doctor if you are pregnant or plan to become pregnant after using this medication.
  • Withdrawal symptoms may occur, such as nausea and vomiting, increased heart rate, sweating, fever, muscle spasms.

Common dosing schedule:


This schedule is for reference only, adjustments may be made according to individual needs.


Some common medications Naloxone may interact with:

  • No known significant interactions.

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Naloxone in Hong Kong?

In Hong Kong, Naloxone is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.


For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Naloxone in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

Brands in Hong Kong
Available dosage
  • 0.4mg/mL (Injections)
Drug class
Sub class
Opioid Antagonists
Other drugs in same class
Used for: Opioid dependence, Alcoholism
Chinese name: