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Adverse Reactions of Mixing Drugs or Alcohol

If you have taken any prescription medication, you have probably been warned about mixing your medicine with certain types of drugs and/or alcohol. Every drug, no matter what type it is, can interact with other substances and produce severe side effects. If you mix drugs recreationally, particularly drugs that you are using illicitly, the risk can be even greater.

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Why Mixing Drugs Is a Bad Idea

There are numerous reasons why you should not mix drugs at all unless you are instructed to do so by your doctor.
  • When drugs have similar mechanisms of action, the effects of both drugs are enhanced. This means that less of the drug is required to get the type of effects that you would normally get from the drug, including potentially dangerous side effects and the potential to overdose on the drug.
  • When drugs have opposing mechanisms of action and you mix them, they can negate the effects of one another, meaning that you would need to take more of the drugs to actually feel the effects. The drugs are still present in your body, and this means that you could risk overdosing on one or both of them by taking too much.
  • When different drugs are mixed in your body, they can produce potentially toxic substances (such as cocaine and alcohol, outlined below), which can lead to unpredictable side effects and organ damage.
  • Mixing different drugs can produce erratic results that can present as serious complications.
  • In some cases, combinations of drugs can be beneficial and are recommended to treat certain conditions. These combinations should only be taken under the supervision of your physician.

Mixing Alcohol & Other Drugs

Recreational drug users combine alcohol with other drugs at a higher rate than any other combination. This is because alcohol is legal and readily available to most people.

Alcohol is a CNS depressant, so it reduces the functioning of neurons in the brain.

The effects of combinations with alcohol will differ depending on the drug used.

Combining alcohol with other central nervous system depressants (like benzodiazepines, opioids, or other sedatives) enhances the effects of both drugs and increases the possibility that you may overdose on one of them.


If alcohol is combined with central nervous system stimulants like amphetamines or cocaine, each drug cancels out some of the effects of the other drug. This makes it very likely that you will take too much of one of them (most often the stimulant).

Other Prescription Drugs

When combined with antidepressant medications and other prescription medications that are typically not drugs of abuse, alcohol can reduce the medication’s effectiveness. The combination can also produce different side effects that can be very distressing.

Over-the-Counter Medications

Chronically combining alcohol with over-the-counter analgesics, such as acetaminophen (Tylenol), ibuprofen (Advil or Motrin), or naproxen (Aleve), can lead to an increased risk for liver damage, ulcers, and cardiovascular issues.


The chronic effects of combining alcohol and tobacco products can lead to numerous long-term health issues, especially an increased risk for many different forms of cancer. This risk is significantly higher than the risk of getting cancer as a result of using either drug alone.

Whenever you drink alcohol, your liver gives priority to metabolizing the alcohol in your system over all other substances.

This means that other potentially toxic substances, like other drugs, are not metabolized until your liver has eliminated the alcohol from your system.

As a result, combining alcohol with other drugs places a significant burden on the liver and the rest of your system. Unless instructed to do so by your physician, you should never combine alcohol with any drug of abuse, prescription medication, or over-the-counter medication.

Other CNS Depressant Combinations

Other central nervous system (CNS) depressant combinations are popular among abusers of this class of drugs. These include:

  • Combining benzodiazepines (Valium, Xanax, and others) and prescription opioids (Vicodin, OxyContin, codeine, and others).
  • Combining different benzodiazepines.
  • Combining different opioid medications or illicit opioids with other opioids. Heroin and fentanyl is a particularly dangerous combination that leads to numerous overdose deaths.
  • Using mild sedatives in conjunction with benzodiazepines or opioids.

Any of these combinations can lead to an enhancement of the effects of the drugs, resulting in potentially dangerous issues. The most serious risk is a severe or even fatal overdose on either drug.

CNS Stimulant Combinations

Stimulant drugs speed up the central nervous system. Combining stimulant medications can enhance their effects. This can result in potentially dangerous issues, such as dramatically increased blood pressure, cardiac issues, stroke, seizures, and psychosis.

The following stimulant medications are commonly abused and may be combined with one another:
  • Methamphetamine (crystal meth or meth)
  • Cocaine in all its forms
  • Prescription drugs to treat ADHD like Adderall or Ritalin
  • Ecstasy (MDMA)
  • Over-the-counter diet medications
  • Antihistamines
  • Other amphetamines (like diet aids)
The same principles regarding enhanced effects and overdose apply to these combinations.

Mixing Stimulants & Depressants

Mixing central nervous system stimulants with central nervous system depressants is not uncommon among people who abuse drugs. Alcohol is the most common central nervous system depressant mixed with stimulant drugs, but other combinations occur, including mixing stimulants with benzodiazepines, opioids, and sedatives.

Typically, people who engage in this practice are trying to “cut” the effects of the stimulant. In some cases, such as the speedball (typically a mixture of cocaine and an opioid like heroin), users are seeking to experience the unique effects of combining the two drugs.

There is a significant risk of overdose in these cases.

Aside from the cancellation of the effects of both drugs that occurs and the potential for overdose on one or both by taking too much of either, there are many potentially dangerous interactions that might occur. For instance, a common combination is cocaine and alcohol, which produces a toxic substance in your liver known as cocaethylene that can result in significant liver damage.

Mixing Over-the-Counter Medications & Prescription Medications

Because of potential untoward interactions that can occur between prescription drugs and medications that you can purchase over the counter, you should never engage in this practice unless you are instructed to do so by your physician.

There are literally thousands of different potential interactions that can occur as a result of this process, many of which produce dangerous side effects.

Cognitive & Emotional Effects

The effects of combining different types of drugs also affect your ability to think clearly, control emotions, or inhibit impulsive behaviors.

If you combine central nervous system depressants, you are more likely to have decreased reaction times, slow rates of thinking, be irrational, and have problems controlling your emotions, leading to emotional outbursts of anger, depression, and even aggression.

Combining stimulant medications often leads to feelings of invulnerability that can lead to significant problems with judgment. It can also result in psychotic-like states due to high levels of excitatory neurotransmitters like dopamine being released in your brain.

Combining drugs with opposite actions nearly always reduces your ability to make quick decisions, think clearly, and control your emotions and impulses. This can lead to numerous issues, including accidents, legal entanglements, and other serious problems.

Using Drugs to Eliminate Cravings

In many cases, there are medicinal effects associated with mixing certain types of prescription medications or in using combinations of medications that you can get over the counter with prescription drugs. For instance, if you mix the opioid antagonist ReVia (naltrexone) with other opioid drugs, you may find that your cravings to use these drugs are reduced, and you use less of them. Using naltrexone to eliminate cravings and cut down on opioid abuse is a common practice.

Obviously, your physician may prescribe you different combinations of medications to treat different conditions. But in these cases, the physician is aware of the potential interactions that may occur and engages in a cost-benefit analysis based on their expertise to determine the treatment that can best address your situation. You should never combine medications or illicit drugs without consulting with your physician.


There are thousands of potential interactions that can occur when you combine different types of drugs. People who abuse drugs will very often combine alcohol with their drug of choice, or they may seek to enhance or decrease the effects of one drug by combining it with another drug. This can be a dangerous practice.

When you combine controlled substances with other drugs without consulting with your physician, you are literally taking your life into your own hands.

There are certain combinations of medications that are beneficial, but all combinations of drugs have potential side effects and risks. You can find more details on the side effects associated with different drug combinations from The Complete Guide to Prescription and Nonprescription Drugs.

You should only combine prescription medications with other drugs if you are instructed to do so by your physician. Never combine illicit drugs of any type.

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