Carfentanil vs. Fentanyl: Which Is More Dangerous?

While fentanyl has some legitimate medical uses, carfentanil is simply too potent to have any use for humans. It is used as a tranquilizer for elephants and other large mammals. In a human user, an extremely small amount can be fatal to the point where it’s fairly hard for a user to intentionally misuse the substance without overdosing.

This table can help you understand the differences and similarities between these two medications:[1,2,15]

Overview of Carfentanil

Carfentanil is an extremely potent synthetic opioid that is sometimes used as a tranquilizer for elephants and other large mammals. It has no legitimate medical uses for humans, as even an extremely small amount can trigger a life-threatening overdose. 

As is true of other synthetic opioids, one of the most immediate dangers of the drug is its ability to cause respiratory depression. Overdose is very likely if the drug is used.

If a person is exposed to carfentanil, naloxone should be immediately administered. Any exposure should be considered a medical emergency, even if the exposure seemed very small.

Carfentanil is a Schedule II substance under the Controlled Substances Act. It’s approved as a tranquilizing agent for elephants and other large animals. It’s not designed—or approved—for treating humans.[17]

Overview of Fentanyl

Fentanyl is a powerful synthetic opioid, although it is not as potent as carfentanil. Keep in mind that fentanyl is already 100 times more potent than morphine, so even though carfentanil is much stronger and more dangerous, fentanyl is already a very potent and dangerous drug. 

Fentanyl is an opioid painkiller with legitimate medical uses for humans, but it is very dangerous when misused. It is a primary driver behind a spike in opioid overdose deaths in the U.S. since it became more widespread on the black market. While other synthetic opioids have also contributed to this spike, it is fentanyl that is most commonly the cause of opioid-involved overdose deaths.

Fentanyl is a Schedule II narcotic under the United States Controlled Substances Act.[2] It’s approved for pain control in humans, and it’s legal to take it with a prescription. It’s illegal to take the drug without a prescription or to buy it from a dealer.

Dangers of Abusing Opioids Like Carfentanil & Fentanyl

Synthetic opioids are potent enough that a first-time abuser of these drugs can easily overdose, which can be fatal. These drugs can significantly weaken a person’s breathing to the point where it stops. This can lead to coma, brain damage (which may be permanent), and death. 

Opioids are very addictive substances. Their regular abuse has the potential to cause a destructive cycle of addiction, abuse, and a decline in physical and mental health as a result of that abuse. 

Opioids can cause physical dependence even with legitimate use. Even if a person isn’t addicted, trying to stop use of an opioid after a period of repeated use can result in unpleasant withdrawal symptoms that can make quitting use difficult. Because of this, medical supervision is always recommended when stopping any kind of sustained opioid use, but particularly opioid abuse.

Key Differences Between Fentanyl & Carfentanil

Neither drug is safe to abuse in any context, but carfentanil is much more dangerous than fentanyl. 

Carfentanil is about 10,000 times more potent than morphine, which makes it exponentially more potent than fentanyl. For context, the DEA states that 2 mg of fentanyl has the potential to be life-threatening to a user, depending on the route administered and certain other factors. 

Carfentanil is so powerful that it’s difficult to call it a drug of abuse in the way that fentanyl and other opioids can be. While there are cases of people intentionally misusing carfentanil, it is so dangerous and used in such small doses that it would be difficult to regularly misuse the drug and survive. Because of this, fentanyl abuse is much more common than carfentanil abuse.

This also means that many more people die of fentanyl overdose than carfentanil overdose. While carfentanil is more potent, fentanyl use is just much more widespread. 

Risk of Overdose

As discussed earlier, all opioids carry a risk of overdose, with fentanyl and carfentanil carrying an extremely high risk of overdose. These overdoses are not isolated incidents. Synthetic opioids have represented a massive spike in fatal overdoses that have contributed to the ongoing opioid abuse epidemic occurring in the United States and elsewhere. 

The reason opioids can be so dangerous is that they activate certain opioid receptors at specific sites in the central nervous system that are critical to how we breathe. Additionally, people often don’t realize just how potent synthetic opioids can be and take too much in an effort to achieve a powerful high. While this is true on some level of most overdoses, as most are accidental, it’s a bigger issue with especially powerful drugs where the margin for error on the part of the user is much lower.

The risk of an overdose being fatal or otherwise causing permanent harm can be reduced by making sure to have naloxone nearby when using opioids. This is a type of drug called an opioid receptor antagonist. It can reverse the effects of opioids in a person’s system, including quickly interfering to stop an opioid overdose. 

What to Do During an Overdose

An opioid overdose is a life-threatening emergency. Without quick treatment, people who experience an overdose can die during the experience. The steps you take can save a life.

An opioid overdose typically involves the following symptoms:[16]

• Extreme sedation
• Pale or clammy skin
• Blue-tinged fingernails or lips Vomiting or gurgling noise
• Coma
• Slow or absent heartbeat

If you think someone is overdosing, call 911 immediately and tell the operator what you’re seeing. While you wait for help to arrive, you can provide critical care.

Naloxone (sold as Narcan) is an over-the-counter medication typically provided as a nasal spray. Put the tip of the nozzle in the person’s nose, and depress the plunger. 

Since fentanyl and carfentanil can be so strong, you may need to give several doses for the best results. Keep administering doses every two to three minutes until the person is breathing independently for at least 15 minutes or help arrives.[1]

If you take any kind of opioid drug, or you spend time with people who do, keep naloxone on hand. Go to your pharmacy, tell the pharmacist you want doses, and you can walk out with them.