What Polysubstance Use Means and Why It Can Increase Overdose Risk 

Understand the risks of taking multiple drugs simultaneously and how it may result in overdose. 

Polysubstance use — taking two or more drugs, either intentionally to boost effects or unintentionally through a contaminated supply — significantly raises the risk of overdose because combined substances produce unpredictable, amplifying effects. Unintentional polysubstance use usually happens through illicit street drugs laced with fentanyl or other substances, and the effects can be especially damaging to the brain and organs, making it far more dangerous than using a single drug. 

How Common Is Polysubstance Use? 

Polysubstance use is currently a key factor driving the overdose crisis in the United States. The illicit drug market is highly unstable, and drugs are often contaminated or “cut” with other substances, exposing many people to multiple substances without their knowledge. This shift has made overdoses more complicated to reverse and more lethal than before. 

Current statistics indicate: 

In 2024, the U.S. experienced 79,384 drug overdose deaths, with an age-adjusted rate of 23.1 per 100,000. 

Provisional data for 2025 indicates a further decrease to around 69,973 deaths, marking a 13.9% reduction from the previous year. 

The percentage of overdose deaths involving 3 or more drugs rose from 51% in 2012 to 74% in 2023. 

The average number of drugs detected per death increased from 1.72 in 2012 to 2.29 in 2023. 

Key combinations driving deaths: 

Fentanyl + Stimulants (“Speedballs” or “Goofballs”): Fentanyl combined with methamphetamine or cocaine is very common in today’s illicit drug supply and significantly contributes to overdose deaths. 

Fentanyl + Xylazine (“Tranq Dope”): Xylazine, a veterinary tranquilizer not approved for human use, is often combined with fentanyl. This combination leads to intense sedation and serious skin wounds, and has become widespread across numerous regions in the U.S. 

Counterfeit Pills: Fake prescription pills, like Percocet, Xanax, or Adderall, often contain fentanyl or other potent substances. Many people unknowingly take these believing they are authentic medications. 

Opioids + Alcohol or Benzodiazepines: Using prescription pain pills, heroin, or fentanyl with alcohol, Xanax, or other sedatives significantly raises the risk of slowed breathing. 

Multiple Sedatives + Fentanyl: Combinations of fentanyl with new or potent benzodiazepines, like bromazolam, or other sedatives. 

Emerging Adulterants: In certain regions, medetomidine, a different veterinary sedative, is increasingly found alongside or replacing xylazine in fentanyl supplies. 

Although overall overdose deaths have decreased recently, the share involving multiple substances keeps increasing. This trend presents distinct challenges for harm reduction, emergency response, and treatment strategies. 

6 Dangers of Intentional Polysubstance Use 

Intentional polysubstance use involves deliberately combining two or more substances, either simultaneously or in quick succession, to achieve specific effects. This practice notably heightens health risks compared to using a single substance. The main dangers of mixing substances include: 

Amplified and Synergistic Effects: Mixing substances can lead to effects that multiply instead of just adding up. This is particularly dangerous with depressants such as opioids, alcohol, and benzodiazepines, which together cause severe slowing of breathing and heart rate, significantly increasing the risk of respiratory failure, unconsciousness, and death. 

Unpredictable and Masking Effects: These effects occur when one drug conceals or counteracts the effects of another. For instance, stimulants like methamphetamine or cocaine can temporarily hide the sedative effects of opioids or alcohol, which can cause someone to unknowingly consume more of the depressant and increase the risk of sudden overdose. The same combination might seem manageable at one moment and become life-threatening the next. 

Increased Overdose Risk: Intentional mixing increases the risk of overdose, even with smaller amounts of each substance. Naloxone (Narcan) can reverse opioid overdoses but is ineffective against stimulants, alcohol, xylazine, or most other drugs, so overdoses involving multiple substances often require more extensive medical treatment. 

Cardiovascular and Organ Damage: Combining stimulants with other substances places intense strain on the heart and blood vessels, increasing the risk of heart attack, stroke, irregular heartbeat, and high blood pressure. Prolonged use can also harm the liver, kidneys, and brain. 

Worsened Mental Health and Cognitive Effects: Using multiple substances together can heighten feelings of anxiety, paranoia, psychosis, and depression, and can impair judgment and decision-making, raising the risk of engaging in dangerous behaviors. 

More Severe Withdrawal and Dependence: Stopping multiple substances at the same time often results in more severe and complex withdrawal symptoms. Dependence develops more quickly and becomes more difficult to treat because the body adapts to several drugs at once. 

Even when substances are combined intentionally and with awareness of the risks, the interactions are often more dangerous than anticipated, due to individual differences in tolerance, substance purity, and other variables. It is never safe to mix substances, especially illicit drugs. 

Frequently Asked Questions 

What is polysubstance use? 

Polysubstance use means taking two or more drugs, either intentionally to combine effects or unintentionally through a contaminated drug supply. It significantly increases the risk of overdose because combined substances produce unpredictable, amplified effects. 

Why is fentanyl mixed with other drugs so dangerous? 

Fentanyl combined with stimulants, xylazine, or other sedatives can mask or amplify each drug’s effects, making overdose more likely and harder to reverse. Naloxone can reverse opioid overdoses but has no effect on stimulants, alcohol, or xylazine. 

Can naloxone reverse an overdose involving multiple substances? 

Naloxone can reverse the opioid component of an overdose, but it’s ineffective against stimulants, alcohol, xylazine, and most other non-opioid substances, so a polysubstance overdose often requires more extensive emergency care. 

How is polysubstance addiction treated? 

Treatment typically combines medication-assisted treatment (MAT) with counseling and behavioral therapies. Because no single medication treats all substances, care is usually part of a comprehensive, individualized treatment plan. 

Medication-Assisted Treatment for Polysubstance Addiction with Middlesex Recovery 

Because polysubstance addiction involves the use of multiple substances, it can be extremely difficult to overcome without professional medical help. At Middlesex Recovery, we understand the heightened risk of overdose for people dealing with multiple addictions, and we treat everyone who walks through our doors with the dignity and respect they deserve, free of judgment. 

Our medication-assisted treatment (MAT) programs combine FDA-approved medications with counseling and behavioral therapies to support addiction recovery. This office-based opioid treatment plays a key role in treating polysubstance addiction, especially when opioids are involved. Since no single medication can treat all substances, MAT is usually part of a comprehensive, individualized treatment plan. 

The highly specialized medical providers and staff at Middlesex Recovery work together to craft the most effective treatment for each patient. If you are struggling with polysubstance use and want to take the first step toward getting help, contact us today. We are ready to help you on a path toward long-lasting recovery and a healthier future.