Naloxone in Colorado: What to Know Before You Need It

Naloxone in Colorado is available over the counter, so you can buy the nasal spray without a prescription. It is a medicine that can reverse an opioid overdose, and federal health agencies say people without medical training can use it. Knowing what it does, how to spot an overdose and what those agencies advise can help you act quickly in an emergency. It also helps to know how Colorado law treats people who call 911 about an overdose.

What is naloxone and how does it work?

Naloxone is a medicine that rapidly reverses an opioid overdose. NIDA explains that it "attaches to opioid receptors and reverses and blocks the effects of other opioids". [Source: NIDA 2022]

The FDA calls it "a life-saving drug that, when sprayed into the nose or injected, quickly reverses the powerful effects of opioids during an overdose". [Source: FDA 2026] The FDA also notes that naloxone has no abuse potential and is not a controlled substance. [Source: FDA 2024]

CDC describes two forms that anyone can use without medical training: a prefilled nasal spray and an injectable. [Source: CDC 2025] Many people call every version Narcan, which NIDA notes was the brand name when naloxone was first approved to reverse opioid overdoses. [Source: NIDA 2022]

Naloxone also has limits. NIDA says it "has no effect on someone who does not have opioids in their system". It is also "not a treatment for opioid use disorder". [Source: NIDA 2022] Treating the disorder is a separate step, and NIDA notes that opioid treatment programs "provide evidence-based care for opioid use disorder". [Source: NIDA 2025]

Can you buy naloxone without a prescription in Colorado?

Yes. CDC states that "Naloxone is available in all 50 states over the counter" and that "You don't need a prescription to purchase naloxone". [Source: CDC 2025]

The first over-the-counter approval came in 2023. On March 29 of that year, the FDA approved a nasal spray as "the first naloxone product approved for use without a prescription". It also said that "Other formulations and dosages of naloxone will remain available by prescription only". [Source: FDA 2023]

The FDA approved a second over-the-counter nasal spray in July 2023 and another in June 2026. [Source: FDA 2023] [Source: FDA 2026] If cost is a worry, CDC suggests checking whether your insurance plan covers naloxone. It adds that "Community-based organizations and local health departments may offer naloxone at little to no cost". [Source: CDC 2024]

What are the signs of an opioid overdose?

CDC lists four signs to look for: no response, trouble breathing, discolored skin and tiny pupils. It also notes that it "may be hard to tell whether a person is high or experiencing an overdose". If you aren't sure, CDC's advice is to "treat it like an overdose". [Source: CDC 2024]

The FDA and NIDA lists overlap with CDC's and add a slow, faint or irregular heartbeat. [Source: FDA 2026] [Source: NIDA 2022]

What should you do if you think someone is overdosing?

CDC's advice starts with two actions: give naloxone if it is available, and call 911. NIDA says people "should still call 911 immediately in the event of an overdose". [Source: NIDA 2022]

Here are CDC's four steps, quoted from its overdose response page. [Source: CDC 2024]

• Administer an overdose reversal medication like naloxone (if available) and call 911.
• Try to keep the person awake and breathing.
• Lay the person on their side to prevent choking.
• Stay with the person until emergency assistance arrives.

The call to 911 matters even if naloxone works. The FDA explains that "naloxone is a temporary treatment, and its effects do not last long". It says to stay with the person, even if they are conscious, until emergency medical help arrives. [Source: FDA 2026] NIDA adds that naloxone works in the body for only 30 to 90 minutes, and "many opioids remain in the body longer than that". [Source: NIDA 2022]

More than one dose may be needed. CDC notes that "More than one dose of naloxone may be required when stronger opioids like fentanyl are involved". [Source: CDC 2025] Each product has its own directions, and NIDA says you "should also read the product instructions and check the expiration date". It also notes that families can ask their pharmacists or health care provider how to use the devices. [Source: NIDA 2022]

Does Colorado protect people who call 911 about an overdose?

Yes, within limits. Colorado lawmakers addressed this in a 2016 law, HB16-1390. Its summary says a person who reports an emergency drug or alcohol overdose event is immune from arrest and criminal prosecution for certain drug-related offenses. That protection applies "if certain conditions are satisfied". [Source: Colorado General Assembly 2016]

A 2023 law, HB23-1167, extended that immunity. Its summary says the protection now reaches a person who "aids or seeks aid for the person suffering the overdose". That holds even if they did not report it to an emergency responder, as long as they meet additional requirements. [Source: Colorado General Assembly 2023]

CDC notes that most states have Good Samaritan laws that protect people who are overdosing and those helping them "from criminal penalties". [Source: CDC 2025] Colorado's protections come with conditions and cover only certain offenses, so this is general information, not legal advice.

Who should carry naloxone, and where can you get it in Colorado?

The FDA recommends that several groups carry naloxone. They include "People who are prescribed medicines to treat opioid use disorder" and "Caregivers of people who are at risk of an opioid overdose". [Source: FDA 2026]

CDC gives a practical reason to tell others you have it: "you can't use naloxone on yourself". [Source: CDC 2025] NIDA says families with loved ones who struggle with opioid addiction "should have naloxone nearby" and let friends know where it is. [Source: NIDA 2022]

To buy it, CDC suggests checking your local pharmacy, convenience store, grocery store or gas station. [Source: CDC 2025] Colorado law also helps get naloxone into communities. A 2025 law, SB25-164, "permits a standing order allowing all eligible entities to distribute opioid antagonists", the class of medicine naloxone belongs to. [Source: Colorado General Assembly 2025]

How Mile High Treatment & Recovery can help

Naloxone can reverse an overdose, but it does not treat opioid use disorder. If you or someone you love is looking for treatment, we are a CARF-accredited opioid treatment program that provides methadone, at 6310 E. Exposition Ave in Denver.

• Hours. We are open Monday to Friday from 5:30 AM to 12:30 PM, and Saturday from 9 to 11 AM.
• Your first visit. Walk-ins are welcome before 11:30 AM, and every new patient has an assessment before treatment begins. See what to expect at your first visit.
• Treatment and support. Alongside methadone therapy, our services include counseling, group counseling, recovery support services and care coordination.
• Coverage. We accept Medicaid and Medicare, including Health First Colorado, Colorado Access, Colorado Community Health Alliance and Rocky Mountain Health Plans. We also offer a sliding scale if you are paying for yourself. See the plans we accept.

Naloxone in Colorado: common questions

Can naloxone hurt someone who is not having an opioid overdose?

The FDA says it generally will not. Its examples of other emergencies include a diabetic coma or cardiac arrest. In those cases, the FDA says naloxone "will generally not have any effect or cause them additional harm". [Source: FDA 2026] CDC says naloxone won't harm someone who is overdosing on drugs other than opioids. FDA official Marta Sokolowska said: "Don't hesitate to administer naloxone in an emergency even if you're not sure if the person is experiencing an opioid overdose". CDC's steps pair naloxone with a call to 911.

Can naloxone cause withdrawal in someone who takes methadone?

It can. NIDA says people with physical dependence on opioids "may have withdrawal symptoms within minutes after they are given naloxone". [Source: NIDA 2022] It also notes that methadone, like many medications, produces dependence. [Source: NIDA 2025] CDC lists possible symptoms including fever, anxiety, irritability, a rapid heart rate, sweating, nausea, vomiting and tremors. [Source: CDC 2024] NIDA calls this uncomfortable but "usually not life threatening". It also says the risk of death from an opioid overdose is worse than the risk of a bad reaction to naloxone. If you take methadone and have questions about naloxone, your care team is the right place to ask.

Does naloxone expire?

Yes. The FDA advises patients and caregivers to go by the expiration date printed on each product's packaging and in its labeling. [Source: FDA 2024] NIDA also recommends checking that date, along with reading the product instructions. If you already have naloxone at home, in a car or in a bag, it is worth checking the date. Because you can't use naloxone on yourself, CDC suggests letting others know you have it. That way, someone nearby knows where to find it in an emergency.

Where to go from here

Naloxone in Colorado is available without a prescription. Knowing the signs of an overdose and the steps CDC describes can help you act quickly. In any emergency, keep 911 and the product's own instructions at the center of what you do. This article is general information, not medical advice.

If you or someone you love wants to talk about treatment for opioid use disorder, call us at 720-756-7162 or get in touch. Our guide to methadone clinics in Colorado explains how to check a program and what to ask.