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4 Facts About Combined Drug Intoxication

By Manjari Bansal
Pursuing a high by taking two or more drugs simultaneously can cause serious and fatal side effects. Here are four important facts about combined drug intoxication.

Combined drug intoxication, also known as multiple drug intake (MDI) or polysubstance use, is when a person misuses more than one drug at the same time. Although people usually combine medications to augment desired effects, this practice may cause serious side effects and life-threatening consequences. Read on for four vital facts about combined drug intoxication. 

Combining drugs may change their effects.

People may intentionally misuse multiple drugs in an attempt to enhance the desired effects. “Typically, opioids, alcohol, and benzos are depressants and cause people to feel more sedated. Cocaine and methamphetamines are considered stimulants and as such, tend to cause people to be more alert, conscious, and agitated,” Monty Ghosh, M.D. and addiction specialist at the University of Alberta Hospital in Edmonton, tells WebMD Connect to Care. 

“Many substances, when mixed, can cause different outcomes,” Ghosh adds. 

In fact, a 2020 review article published by Frontiers in Neuroscience notes that there is scientific evidence for the following:

  • Opioids may increase the rewarding and motivational effects of psychostimulants like cocaine and methamphetamine—especially when these two types of drugs are taken simultaneously.
  • The simultaneous use of cocaine and nicotine is widely reported to have addictive and synergistic effects. 
  • Cocaine and cannabis, when used together, can produce a longer-lasting high than when each drug is used alone. 

Side effects of combined drugs can be dangerous.

Every drug has its own short-term and long-term side effects. But when someone combines drugs with other drugs or alcohol, it can lead to significantly harmful side effects, states Mayo Clinic.

For example, the common "club drugs" GHB (gamma-hydroxybutyric acid) and flunitrazepam may cause confusion, sedation, and memory loss when taken together. The danger increases when these drugs are taken in high doses or with alcohol, which can result in seizures, coma, and death.

“Adverse outcomes can be made worse when combining substances. For example, when mixing cannabis and methamphetamines, the risk of psychosis increases drastically. We do see this with other substances as well, such as mixing fentanyl and methamphetamines,” Ghosh adds.

Risk of overdose is heightened with multiple drug intake.

According to a 2019 study published in Tidsskr Nor Legeforen, The Journal of the Norwegian Medical Association, combining drugs is a leading cause of lethal overdose. Also, multiple drug use is typically associated with greater treatment needs.

The study was conducted to investigate 194 deaths due to overdose in Norway. It found that taking multiple drugs in combination (especially opioids and benzodiazepines) was the main cause of death due to overdose. In fact, mono-intoxication with heroin was not found in any of the 194 overdose deaths.

Overdose due to polysubstance use is more difficult to treat.

According to the 2020 study published in Frontiers in Neuroscience, the misuse of multiple drugs is associated with worse treatment outcomes, including:

  • Higher incidences of relapse
  • Reduced treatment retention
  • A three-times higher mortality rate when compared to single substance abuse

“It is often difficult to treat one particular substance toxicity, and as such, one needs to target the most dominant and overused substance as the primary substance before attempting to control the others,” Ghosh says.

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