Both heroin and alcohol have the same overall effects, as they are central nervous system depressant drugs. Heroin is an opiate drug that primarily affects the endogenous opioid receptors in the brain, whereas alcohol affects the release of the inhibitory neurotransmitter gamma aminobutyric acid (GABA) and the excitatory neurotransmitter N-methyl-d-aspartate (NMDA). Alcohol increases the effects of inhibitory neurotransmitters and decreases the effect of excitatory neurotransmitters.

Regular use of both of these drugs affects other neurotransmitters, such as dopamine, by increasing its availability when reinforcing experiences are repeated. Because alcohol and heroin have similar overall effects, but primarily work on different neurotransmitter systems, using both drugs together enhances the effects of each drug and at the same time results in different sensations and experiences than using either drug alone.

According to the books Alcohol and Opiates: Neurochemical and Behavioral Mechanisms and Drug and Alcohol Abuse: A Clinical Guide to Diagnosis and Treatment, the effects of combining alcohol and heroin are many.

An increase in the physical effects of both drugs will occur, such as a significant decrease in the firing of the neurons in the brain, a significant decrease in breathing rate, a significant decrease in heart rate and blood pressure, and substantial issues with balance and motor coordination. This will lead to extreme lethargy.
An increase in the cognitive effects from both drugs will occur, including significantly slow rates of thinking, loss of inhibitions, loss of rational thinking abilities, issues with attention and concentration that can be serious, issues with developing new memories, and issues with problem-solving that can be very severe.
There will be an increase in the emotional effects that occur with both drugs, including loss of emotional inhibition (inability to control spontaneous feelings). At high doses, there may be an increase in negative emotional states, such as depression, sadness, and anxiety, and potential psychosis (hallucinations and/or delusions).
There is a significant increase in the potential to overdose on either drug. Most likely, individuals using heroin and alcohol will take significantly larger amounts of alcohol than heroin, and issues associated with high levels of alcohol use can include alcohol poisoning and alcohol overdose. Heroin overdose is also possible because using both drugs together lowers the threshold at which an individual can overdose on either drug.
Unpredictable side effects or drug interactions can occur when individuals use these drugs in combination.
Because of the detrimental effects on an individual’s thinking abilities and their motivation to engage in self-care, they also become more likely to engage in risky behaviors that can be potentially damaging. This can include needle sharing, operating machinery, engaging in criminal activities, becoming victims of crimes, and even developing suicidal ideations that can lead to self-harm.
Opiates like heroin often have the effect of inhibiting the vomiting reflex when individuals become nauseous. This can increase the potential for one to overdose on alcohol or experience alcohol poisoning.

There are also various long-term effects.

There is an increased potential to develop damage in numerous organ systems. This occurs as both a direct effect of these drugs, and the effect of suppressing heart rate and breathing rate. Chronic issues with hypoxia (decreased oxygen) can result in significant tissue damage to all major organs, but the brain is particularly vulnerable to this.
There is the potential to develop liver damage as a result of cirrhosis and overburden the liver when these drugs are combined.
Significantly decreased efficiency of the immune system can occur, which can result in increased susceptibility to infectious disease.
There is increased potential to develop other chronic conditions, including all forms of cancer, gastrointestinal issues (e.g., ulcers), issues with the kidneys, and cardiovascular issues.
Physical dependence on one or both drugs is likely in chronic users.
The development of a substance use disorder to one or both drugs is significantly increased in chronic users.

These potential risks can result in numerous issues with the individual’s level of functioning. For instance, an overdose on either drug can be fatal; overdose on either drug while under the influence of the other drug is much more likely, and more likely to result in serious physical and cognitive issues as a result of anoxia (a complete cutoff of oxygen to the brain and other organs). The brain is particularly vulnerable to decreased oxygen or a lack of oxygen, and important areas of the brain begin to die within only a few minutes of oxygen deprivation. Even if an individual is revived, they may suffer long-term cognitive effects that can be quite severe. Obviously, the potential for fatality exists as a result of an overdose.

Concerns of Mixing Alcohol with Other Opiates

Other Ramifications

In addition to the other risks mentioned above, individuals who chronically abuse any substance are far more likely to experience:

Significant dissatisfaction with life, which is often paradoxical because individuals use drugs in an attempt to improve their subjective outlook or feelings
Significant involvement in the legal system, such as being charged with criminal activities, incarceration, etc.
Increased risk for physical, cognitive, or emotional injury as a result of being a victim of a crime or abuse
Dysfunction or impairments with one’s career or education
Significant problems with personal relationships that may often not resolve fully
Financial difficulties
Being diagnosed with some other form of mental illness
The need for extensive and long-term treatment of one’s physical, psychological, and social situation

When individuals combine powerful drugs of abuse, the risks of suffering any of the issues mentioned above are increased. Individuals with polysubstance use disorders have significant complications that further affect their recovery.

The Road to Recovery

The National Institute on Drug Abuse (NIDA) has outlined the principles of effective treatment programs for substance use disorders that apply to any individual who has chronically abused heroin and alcohol. The program of recovery for these individuals should include certain factors.

A comprehensive assessment of the person’s situation should be performed by licensed medical and mental health professionals.
Initial placement in a physician-assisted withdrawal management program (a medical detox program) is needed. Withdrawal from alcohol can be potentially fatal; withdrawal from heroin is extremely uncomfortable and may lead to issues with suicidality and increased potential to overdose during a relapse. Inpatient admission is required.
During the withdrawal management process, behavioral interventions should be initiated, including therapy and peer support group participation.
Support from the individual’s family members is a crucial factor. Family involvement should be instituted as soon as possible.
Following the withdrawal management program, the person should:
- Continue to receive medical management of psychiatric and physical issues
- Continue to be involved in therapy (individual, group, or a combination of these)
- Continued to be involved in peer support groups (e.g., 12-Step groups)
- Become involved in other interventions as identified in the assessment
- Be monitored for abstinence (often via random drug and alcohol screenings)
It is important that any identified co-occurring mental health conditions be treated concurrently with the individual’s substance use disorders in order to ensure a successful overall recovery process. This intervention for co-occurring disorders should be initiated immediately and continue throughout the treatment process.
The general approach to treatment for substance use disorders remains the same for all individuals and for different types of substances of abuse; however, each program should be individualized to suit the needs of the person in treatment.
Treatment is not a short-term consideration. Recovery is a lifelong venture.

Mixing Heroin & Alcohol

Concerns of Mixing Alcohol with Other Opiates

Other Ramifications

The Road to Recovery