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How long does naloxone block opiates?

Medically reviewed by Leigh Ann Anderson, PharmD Last updated on Jun 11, 2020.

Official Answer

by Drugs.com

Key Points

  • In general, the duration of action of naloxone (brand examples: Narcan, Narcan Nasal, Evzio, generics) ranges from 30 to 120 minutes, depending upon the dose and how it is given. However, some patients may need repeat doses of naloxone.
  • The duration of action of naloxone may not be as long as the duration of action of most opioids (narcotics) involved in an overdose. This can increase the risk for further problems with breathing, extreme sedation or inability to respond when the naloxone starts to wear off.
  • Seek immediate emergency medical assistance (call 911) after giving the first dose of naloxone and keep the person under surveillance until emergency help arrives. Repeat doses of naloxone may be needed.

What is naloxone?

Naloxone is a treatment often used to reverse the effects of an opioid overdose.

Prescription opioids are narcotic drugs often used for moderate-to-severe pain and include medicines such as hydrocodone, oxycodone, fentanyl and morphine. Heroin, an illegal drug of abuse, is also an opiate.

Naloxone is classified as an opioid antagonist which means that it blocks opiate receptors in the brain and other areas of the body. Naloxone and opioids compete for the same receptor sites. By occupying the receptor and blocking the action of the opioid, naloxone can help to reverse the dangerous effects of an opioid overdose.

Evidence suggests that naloxone reverses opioid effects by competing for the opiate receptor sites in the central nervous system (CNS), with the greatest affinity for the mu receptor.

Does naloxone work for buprenorphine?

The effects of naloxone on slowed or stopped breathing by partial agonists or mixed agonist/antagonists, such as buprenorphine and pentazocine, may be incomplete and may require repeat doses or higher doses of naloxone.

For example, buprenorphine has a long duration of action in the body and is more slowly displaced from the opioid receptor. Larger or repeat doses of naloxone hydrochloride may be needed to block buprenorphine effects and to reverse prolonged respiratory depression.

Where can I get naloxone?

Naloxone is now available at most major U.S. pharmacies without a prescription. If you or anyone in your family takes opioid medications, you should strongly consider having naloxone on hand for an emergency situation. Overdoses can occur by accident or intentionally.

Patients and family members or caregivers, once they get their naloxone product, should read the FDA-approved patient labeling before an emergency occurs. In those that elect to carry the devices or store these medications in their home, learning how to use them ahead of time can save important time.

Naloxone comes in different forms and can be given either as an injection or a nasal spray. Some forms of naloxone are more user-friendly and can be given by the lay public, family members, caregivers or friends until emergency medical help arrives. These agents include naloxone nasal sprays (brand name example: Narcan Nasal) and an auto-injector (brand name example: Evzio).

How much does naloxone cost?

Narcan Nasal Spray

  • Narcan Nasal Spray is available from your pharmacist in every U.S. state. You do not need a prescription from your doctor.
  • Narcan Nasal Spray, from Adapt Pharma, is covered by most insurance plans with an insurance copay of $20 or less. Government insurance plans also cover Narcan Nasal Spray.
  • If you are paying cash, Narcan Nasal Spray 4 mg averages about $130 to $140 for a carton of 2 sprays using an online discount coupon.

Evzio Auto-injector

The Evzio auto-injector is another user-friendly option to rapidly administer naloxone in the setting of a known or suspected opioid overdose. From the manufacturer Kaleo, Evzio is an auto-injector that the user injects into the thigh of the person who has overdosed. It can even inject through clothes.

Evzio delivers a single naloxone dose via a hand-held auto-injector that can be carried in a pocket or stored at home. When Evzio is turned on, it provides verbal instructions to the user. Visual instructions are also available.

  • The cost for the brand name of Evzio injectable solution (2 mg/0.4 mL) is expensive if you are paying cash. However, an authorized generic option is now available and is much more affordable.
  • The authorized generic of Evzio (naloxone) 2 mg ranges from $150 to $200 for a carton of two auto-injectors. Again, this is for cash-paying customers using an online discount coupon. Insurance plans may cover the authorized generic for Evzio auto-injector, so be sure to check with them first.
  • The brand product Evzio 2 mg/0.4 mL costs around $4,300 to $5,000 for 2 auto-injectors, depending on the pharmacy you visit, but there’s no reason to pay this price now that the authorized generic is available.

Any form of naloxone is NOT a substitute for emergency medical care, and 911 or other emergency medical care should be contacted immediately after administering naloxone in any form.

Bottom Line

The action of naloxone can last from 30 to 120 minutes, depending upon the dose and how it is given. However, some patients may quickly need repeat doses of naloxone because the duration of action of naloxone is shorter than most opioids (narcotics). This can increase the risk for further problems with breathing, extreme sedation or inability to respond when the naloxone starts to wear off.

Always seek immediate emergency care (call 911) after giving the first dose of naloxone and keep the patient under surveillance until emergency help arrives.

User-friendly versions of naloxone are available in the U.S in a nasal spray form or as an auto-injector. These products are easily accessible from your pharmacist, are often covered under insurance plans, and have become more affordable for patients who need to pay cash. Anyone who uses an opioid should consider having naloxone available for an emergency.

This is not all the information you need to know about naloxone for safe and effective use in an emergency overdose. Review the full naloxone information here before an emergency situation, and discuss this information with your doctor or other health care provider.

References
  • Authorized Generic for Evzio. Naloxone HCL auto-injector [Package Insert]. Accessed June 10, 2020 at https://naloxoneautoinjector.com/
  • Narcan (naloxone) [Package Insert]. Revised March 2020. Adapt Pharma. Plymouth Meeting, PA Accessed June 10, 2020 at https://www.narcan.com/static/NARCAN-Prescribing-Information.pdf
  • Naloxone injection. [Package insert]. DailyMed. US National Library of Medicine. Accessed June 10, 2020 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=73c1bad3-6ac3-8682-e053-2a91aa0a176a
  • Naloxone hydrochloride. Injection. Drugs.com. Accessed June 10, 2020 at https://www.drugs.com/pro/naloxone.html

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