Comparing Opioid Overdose Treatments: 4 Differences Between Zimhi and Narcan

While opioids can be effective at treating pain, they have major risks: physical dependence, misuse, and overdose. If you or a loved one is prescribed opioids, it’s a good idea to carry naloxone, a medication that can reverse the effects of an opioid overdose.

Naloxone is part of a group of medications called opioid antagonists, also known as opioid blockers. It’s available as a nasal spray and injection under several brand names. Many people know it as Narcan. But another naloxone product, Zimhi, is also available.

Here, we’ll compare Zimhi and Narcan and discuss four major differences between them.

1. Zimhi is an injection, and Narcan is a nasal spray

Zimhi and Narcan come in different forms. Zimhi is an injection that comes in a syringe (called an autoinjector). Each syringe can be used once. Zimhi can be injected into the muscle or beneath the skin. You can give the injection through clothing if needed.

Like Zimhi, Narcan comes as an injection that can be injected into the muscle or beneath the skin. Unlike Zimhi, a Narcan injection comes in a vial. You have to draw up the medication yourself using a needle and syringe. Narcan also comes as a nasal spray. You can spray it into one nostril of the person experiencing the overdose (while they’re lying on their back). Each nasal spray is for one-time use only.

If you think you’ve witnessed an opioid overdose, give a dose of Zimhi or Narcan right away if you have it. Then call 911 and request emergency help. The person will need medical care, even if Zimhi or Narcan works. This is because naloxone lasts a maximum of 90 minutes in the body. Many opioids last longer than this. So someone may continue to feel the effects of an opioid overdose after Narcan wears off.

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If a person doesn’t respond within 2 to 3 minutes after giving a dose of naloxone, give a second dose. Repeat this process every 2 to 3 minutes until the person resumes breathing or emergency medical personnel arrive. If you’re using a Zimhi or Narcan injection, change the area where you inject it with each dose. If you’re using Narcan nasal spray, alternate nostrils with each dose.

2. Zimhi contains more naloxone than Narcan products

Zimhi contains 5 mg of naloxone, while Narcan nasal spray contains 4 mg of naloxone. Injectable Narcan is available in 0.4 mg/mL and 1 mg/mL vials.

Research shows that most opioid overdoses that occur where naloxone is available require multiple doses of naloxone. In these overdoses, the higher dose of naloxone in Zimhi may be beneficial — especially those overdoses involving potent synthetic opioids like fentanyl. However, it’s not clear whether one type of naloxone leads to better outcomes. So we don’t know if using Zimhi reduces the need for additional doses of naloxone. More research is needed to determine this.

3. Zimhi and Narcan may be harder to administer in certain situations

The package labeling for Zimhi indicates that only people who are at least 12 years old should administer it. Narcan doesn’t have a minimum age requirement for administration. Even so, a child may have trouble administering injectable Narcan.

It may be hard to inject Zimhi and Narcan if you have weak or limited hand strength. The plunger on the Zimhi syringe must be pressed while keeping the needle in place. It may also be harder to give someone an injection than it is to administer a nasal spray.

Both Narcan and Zimhi need to be administered by someone other than the person experiencing an overdose. In other words, if you’re having an opioid overdose, you can’t give either medication to yourself.

4. Narcan is available over the counter but Zimhi isn’t

Narcan nasal spray is available over the counter (OTC) as of September 2023. So you don’t need a prescription for it. You also don’t need to talk to a pharmacist to get it.

Zimhi and injectable Narcan aren’t OTC. But they can be purchased in most pharmacies in all 50 states and in the District of Columbia. A prescription usually isn’t required for purchase, but policies may depend on the pharmacy.

There are also various ways to get naloxone products for free, including through various state programs and nonprofit organizations. If you have health insurance, it may cover the cost of your naloxone product as well.

What are the side effects of Zimhi and Narcan? [Side effects]

Zimhi and Narcan contain the same medication, so they may have similar side effects. This includes nausea, dizziness, and increased blood pressure. Narcan nasal spray can also cause certain side effects that are related to your nose, like dry nose or congestion. 

Keep in mind that some side effects — like nausea, high blood pressure, and headache — are also symptoms of opioid withdrawal. Zimhi and Narcan can lead to opioid withdrawal after you use them because they reverse the effects of opioids. While opioid withdrawal can be uncomfortable, it isn’t life-threatening.

Other symptoms of opioid withdrawal include:

• Body aches

• Runny nose

• Sneezing

• Nervousness

• Sweating

• Diarrhea

Both Zimhi and Narcan have a low risk of serious side effects. Even if they’re given to someone who’s not experiencing an opioid overdose, they aren’t known to cause harm.

If you suspect someone is experiencing an overdose, it’s best to give a dose of whatever naloxone product you have, even if you’re not sure opioids are involved. If opioids are involved, naloxone could save a life.

So is Zimhi or Narcan a better option?

When comparing Zimhi versus Narcan, one isn’t necessarily preferred over the other. It depends on your situation and preferences. For example, if you prefer to use a nasal spray, you may prefer Narcan. And Narcan nasal spray likely costs less and is available OTC. But if you want to have a higher dose of naloxone, you may prefer Zimhi.

Talk to your healthcare provider or pharmacist about your preferences and concerns. They can help you choose the best product for you.

How to save on Zimhi and Narcan

Zimhi is only available as a brand-name medication. If you have commercial insurance, you may be eligible to receive Zimhi for free using a copay savings card from the manufacturer.

Narcan is available as both a brand-name and generic medication. You don’t need a prescription for Narcan nasal spray, and it’s available OTC for about $45. But GoodRx can help you save up to 75% off the average retail price if you obtain a prescription for it. A pack of two generic Narcan nasal sprays at certain pharmacies may be as low as $37.65 with a free GoodRx discount.

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Written by:

Abe Amos, PharmD

Abe Amos, PharmD, is a clinical advisor for health plans and has experience working with large national government-funded programs. He is a postgraduate year 1 (PGY-1) managed care residency coordinator and also has community retail pharmacy experience.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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