Dangers of Mixing Fentanyl With Other Substances

Mixing fentanyl with other substances can be a dangerous practice that can result in negative health effects.¹ Although polysubstance use can have a devastating impact on a person’s life and the lives of those around them, evidence-based addiction treatment can lead to positive outcomes for a person’s health and overall wellbeing.^{1, 2}

What is Polysubstance Misuse?

Polysubstance abuse means that a person uses more than one substance at a time.¹ This can occur intentionally, meaning the person is aware that they are using more than one substance, or unintentionally, meaning the person is not aware that they are using other substances. In the case of fentanyl, many individuals in the US may purchase illicit street drugs such as cocaine and heroin that are contaminated with fentanyl, leading to unintentional polysubstance misuse.¹

Whether it’s intentional or unintentional, polysubstance misuse can be very dangerous due to potential interactions between substances, which may lead to unpredictable and negative health outcomes, including fatal overdose.^{2, 3}

Mixing Fentanyl With Other Substances

Fentanyl is a substance with a high potential for misuse, addiction, and overdose, regardless of whether you use it with other substances or use it as a prescription medication.⁴ It is a potent synthetic opioid that is 50-100 times more powerful than morphine.⁴ Synthetic opioids like fentanyl are the most commonly found drugs in overdoses in the U.S.⁴

Illicit fentanyl is often added to other illicit substances because it is low-cost and can increase the high of those drugs, but fentanyl interactions with other substances can be dangerous and potentially lethal.⁴ Mixing fentanyl with any of the drug categories mentioned below has the potential to cause a number of detrimental side effects.⁴

Mixing Fentanyl and Depressants

The dangers of mixing fentanyl with other substances that have the potential to depress respiration, such as alcohol, other opioids like heroin, or benzodiazepines, can result in serious side effects.⁵  According to the U.S. Food and Drug Administration (FDA), mixing these substances with fentanyl can lead to dangerous effects such as severely slowed breathing, difficulty breathing, decreased heart rate and blood pressure and death.⁵

People who mix these substances should seek immediate medical attention if they or someone else experience symptoms such as unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness.⁵

Fentanyl and Alcohol

One of the primary dangers of mixing fentanyl and alcohol is that they can both cause respiratory depression.⁵ Alcohol can also increase the sedating effects of opioids like fentanyl.⁶ Some other common risks and effects of mixing alcohol and fentanyl or other opioids can also include:

• An increased risk of overdose.⁷
• Increased drowsiness.⁶
• Sedation.
• Decreased motor skills.⁶
• Death.⁵

Fentanyl and Heroin

Illicit drug deals may mix fentanyl and heroin because it is inexpensive and can increase the user’s high.⁴ Fentanyl works in a similar way to heroin, but it is much stronger, so it can easily overwhelm the bodies of people who are using contaminated heroin but think they are just using heroin alone.⁴

Using heroin with fentanyl can significantly increase the risk of non-fatal and fatal overdose.¹ Additionally, heroin and fentanyl can both increase the risk of slowed breathing, breathing difficulties, sedation, and loss of consciousness, which can lead to coma and permanent brain damage.^{3, 4, 8}

Mixing Fentanyl and Benzodiazepines

Benzodiazepines are sedative drugs that may be prescribed to treat anxiety or insomnia, but they are also increasingly found in the illicit drug market.^{9, 10} Mixing fentanyl (and other opioids) with benzodiazepines has been associated with higher risks of drug-related emergency room visits, hospitalizations, and overdose deaths.^{9, 10}

While the unpredictability of the effects of mixing fentanyl and benzodiazepines make them a dangerous combination, a few common side effects of the mixture may include:¹⁰

• Sedation.
• Dizziness or lightheadedness.⁵
• Extreme sleepiness.⁵
• Slowed or difficult breathing.⁵
• Unresponsiveness.⁵

Mixing Fentanyl and Stimulants

People may intentionally mix fentanyl with stimulants, such as cocaine, methamphetamine, or prescription stimulants, to experience euphoria or other desirable effects.¹¹ Some may also use stimulants to offset withdrawal effects associated with fentanyl.¹¹ However, mixing stimulants and fentanyl can increase the risk of negative health effects.¹¹ While there have not been many studies on humans regarding the exact effects, researchers know that the combinations can be potentially lethal.¹²

Fentanyl and Cocaine

Mixing opioids like fentanyl with cocaine, a practice known as speedballing, can be very risky and lead to detrimental and unpredictable consequences, including overdose.^{11, 12} While early studies suggest the combination to be dangerous, more research is needed to determine the full range of effects of mixing fentanyl and cocaine. ^{11, 12} One report indicates that the increased risk of overdose from mixing fentanyl and cocaine may occur because cocaine causes severe vasoconstriction, or narrowing of blood vessels, which causes the body to require increased oxygen, while fentanyl can cause slow breathing and respiratory failure.¹¹ Another study reports that the risk of overdose due to fentanyl may particularly increase once the stimulating effects of cocaine subside.¹³

Additional negative effects associated with the combination of fentanyl and cocaine may also include:

• Constricted arteries.¹²
• Hyperkinetic cardiac arrhythmias.¹²
• An increased risk of addiction.¹⁴

Fentanyl and Meth

Mixing meth and opioids like fentanyl, a practice known as goofballing, may produce similar effects to the combination of fentanyl and other stimulants, but as with cocaine, there have not been many human studies on these effects.^{12, 15} However, researchers know that polysubstance use involving stimulants is associated with poor physical and mental health, increased hospitalizations for complications due to infections, and increased overdose risk and mortality.¹⁵ Additionally, rates of overdose and fatalities involving meth and opioids like fentanyl have increased in recent years, suggesting a larger problem of polysubstance misuse emerging around meth and fentnayl.¹¹

Finding Polysubstance Misuse Rehabs

If you or someone you care about use fentanyl and other substances, or street drugs that might be contaminated with fentanyl, you should understand the dangers and know how to seek help. Effective treatment for polysubstance misuse involving fentanyl can help people safely stop using these substances, start the path to recovery, and resume productive lives.²

Additionally, those who are not yet ready to seek addiction treatment can still take steps to reduce their risk. For example, carrying fentanyl test strips can be a good way to reduce the risk of fentanyl overdose. These tools can help you test a substance to determine if it has been contaminated with fentanyl, allowing you to make informed decisions. Carrying Naloxone with you can also increase safety. Naloxone, also known by its brand name Narcan, is a powerful medication that can reverse the effects of an opioid overdose. As such, it can be a life-saving tool if you or a loved one is experiencing a fentanyl overdose.

When you’re ready to start the recovery process, you might first consult your doctor to have an evaluation, discuss your unique circumstances and needs, and ask for referrals to rehabs. You can also use the fentanyl support treatment directory to search through thousands of rehabs across the country. Or call American Addiction Centers free and confidential helpline at to speak to a caring and knowledgeable admissions navigator, who can help you learn more about your rehab options and verify your insurance.