According to data provided by the Substance Abuse and Mental Health Services Administration (SAMHSA), alcohol is commonly used and abused with over-the-counter medications, prescription medications, and illicit drugs.

When taken with over-the-counter drugs and prescription medications, alcohol can reduce the effectiveness of these medications and lead to significant interaction effects that can be potentially dangerous. When mixing alcohol with illicit drugs, the effects will vary depending on the major action of the drug.

Per various sources, such as the books Drug-Drug Interactions, The Complete Guide to Prescription and Nonprescription Drugs 2016/2017, Drugs Facts and Comparisons 2017, as well as SAMHSA and the National Institute on Drug Abuse (NIDA), the effect alcohol has on drugs will vary depending on the type or class of drugs alcohol is taken in conjunction with. A brief description of the general effects that result when one mixes alcohol with various classes of drugs follows.

Using Alcohol in Conjunction with Antidepressant Drugs

Antidepressant drugs are medications that are specifically developed to treat clinical depression. These drugs belong to several different classes of drugs, and the use of alcohol has a differential effect on the drug depending on the class of drugs. One of the most common reasons for using alcohol in conjunction with antidepressant drugs is to achieve some sort of enhanced psychoactive effects from the drug itself; however, these drugs do not produce feelings of elation or euphoria in most people.
mixing alcohol antidepressant
The major effects of using alcohol in conjunction with most antidepressant drugs include:

Inhibiting the medicinal effect of the antidepressant drug
Issues with drowsiness, dizziness, and even an increase in one’s level of depression
An increase in the effects of the alcohol, particularly in one’s motor functioning, such as coordination and a reduction in reaction time
An increased potential for damage to organs, such as the liver

Certain classes of antidepressant drugs may be deferentially affected by the use of alcohol. For example, drinking certain brands of beer or red wine may result in an increase of one’s intake of tyramine, an amino acid, which when consumed with drugs in the class known as monoamine oxidase inhibitors can lead to an increased potential for a stroke or heart attack as a result of a significant rise in blood pressure. Fortunately, drugs of this class, such as Nardil (phenelzine) and Parnate (tranylcypromine), are rarely prescribed for the treatment of depression these days.

Mixing Alcohol and Anticonvulsant Drugs

Anticonvulsant drugs include several classes of drugs that are prescribed to control seizure activity or as mood stabilizers. In some cases, benzodiazepines and even barbiturates may be prescribed for seizure control; however, the effects of alcohol with these two classes of drugs will be explained below. Instead, antiepileptic drugs that are not benzodiazepines and barbiturates include drugs like Topamax (topiramate), Neurontin (gabapentin), Lamictal (lamotrigine), and Tegretol (carbamazepine). Drinking alcohol while taking these drugs can result in:

A decrease in the drug’s ability to control seizure activity, resulting in an increased risk that one will have seizures
Generalize effects that can include dizziness, lethargy, and issues with motor functioning, including coordination and reaction time
Increases in depression and suicidality

The Use of Alcohol with Medications to Control High Blood Pressure

Mixing Alcohol Medications Control High Blood Pressure
Medications designed to control high blood pressure are referred to as antihypertensive medications. There are numerous drugs on the market that are prescribed for the control of high blood pressure, including Lopressor (HCT hydrochlorothiazide), Norvasc (amlodipine besylate), and Accupril (quinapril).

When an individual mixes alcohol with antihypertensive medications, they may experience:

Increased high blood pressure due to the antihypertensive medication being less effective when taken with alcohol
Other cardiovascular issues, such as an irregular heartbeat
Dizziness and even fainting spells

Alcohol Use and Medications to Control Diabetes

There are numerous prescription medications that are used to control diabetes, including insulin for type I diabetes and Glucophage (metformin) to control issues associated with type II diabetes. When an individual with diabetes drinks alcohol, this alone can result in a potentially serious situation due to the high sugar content of many alcoholic beverages.

The effect of alcohol on medications to control diabetes can include:

Serious issues with rapid heartbeat and increased blood pressure
Fatigue, weakness, dizziness, headache, nausea, and/or vomiting
Dangerous alterations in blood sugar levels

Alcohol Use and Central Nervous System Depressant Drugs

The central nervous system (CNS) consists of the brain and spinal cord. Numerous prescription medications, over-the-counter medications, and illicit drugs have CNS depressant effects. The CNS depressant slows the functioning of the brain and spinal cord.

Alcohol itself is a major CNS depressant. Some of the major CNS depressant drugs include:

Prescription drugs used to treat issues with anxiety, including benzodiazepines and barbiturates: Benzodiazepines consist of well-known drugs such as Xanax (alprazolam) and Valium (diazepam) and numerous other drugs. The class of barbiturates consists of drugs like phenobarbital and Seconal (secobarbital). These drugs are also notorious drugs of abuse and often used to enhance the effects of alcohol.
All drugs that have a sedative or hypnotic effect, or that act as muscle relaxants: This includes Ambien (zolpidem), Flexeril (cyclobenzaprine), etc. This category includes drugs that are designed to induce or maintain sleep.
A large number of drugs that are classified as pain relievers: This class includes prescription opiate or narcotic medications, such as morphine, OxyContin (oxycodone), Vicodin (acetaminophen and hydrocodone), Norco (acetaminophen and hydrocodone), etc. This class also includes a number of illicit drugs, including heroin. Many over-the-counter pain relievers like acetaminophen (e.g., Tylenol), ibuprofen (e.g., Advil), and aspirin also suppress functions of the central nervous system.

Alcohol Use and Central Nervous System Depressant Drugs
Numerous effects can occur when one mixes CNS depressants. The danger associated with mixing CNS depressants is that the effects of both drugs are enhanced. This can result in an increased potential for overdose on either drug, dangerously reduced functioning in areas of the brain that control life-sustaining functions like breathing and heart rate (which can lead to potential organ damage or fatalities), significantly decreased judgment, and substantial issues with motor functioning, including response time, motor coordination, etc.

Individuals can also experience significant issues with:

Potential liver damage as a result of chronically mixing alcohol and central nervous system depressants, which can even occur with over-the-counter drugs like acetaminophen and ibuprofen products
Potential cardiovascular damage as a result of mixing these drugs
A decrease in breathing rate produced by both drugs, which can leave one open to serious respiratory damage and/or disease (far more likely with prescription and illicit drugs in this category)
The development of significant issues with emotional functioning, including depression, anxiety, and other issues

Alcohol and CNS Stimulants

While alcohol suppresses the functions of the CNS, there are numerous drugs that speed up CNS functions. Several different classes of drugs have this effect, including:

Amphetamines that are used as dietary aids or to treat conditions that result in lethargy or sleepiness
Prescription medications for the treatment of ADHD (attention deficit hyperactivity disorder), such as Ritalin and Concerta (methylphenidate) or Adderall (amphetamine and dextroamphetamine)
Caffeine and several drugs classified as antihistamines or decongestants
Numerous illicit drugs, particularly cocaine and methamphetamine (crystal meth)

When individuals use alcohol with CNS stimulants, they typically are attempting to deaden the effect of the stimulant as opposed to suppressing the effects of the alcohol. The use of alcohol and stimulants is a very common practice among college students who abuse medications designed to treat ADHD in an effort to help them study. Individuals who use illicit stimulant drugs, such as cocaine, commonly use alcohol to “take the edge off” the stimulant drug.

Combining alcohol and central nervous stimulants results in the potential for several serious issues.

When stimulants are used for medicinal reasons, the effect of the stimulant is negated by alcohol.
Taking stimulants and alcohol in combination leads to a significant reduction in the overall effects of both drugs that can result in an individual overdosing on one or both drugs.
There are serious potential neurological issues that can develop when one combines alcohol with stimulants, including increased development of seizures and/or an increased potential to develop psychotic behavior, such as hallucinations or delusions.
Serious effects occur in numerous organ systems, including the central nervous system, cardiovascular system, liver, and gastrointestinal system as a result of chronic abuse of alcohol and central nervous system stimulants.
When an individual combines cocaine with alcohol, this produces a toxic substance known as cocaethylene. This substance can increase the potential for damage to numerous organ systems.
Numerous other emotional issues can occur as a result of chronically mixing alcohol and stimulant drugs, including increased issues with depression, anxiety, loss of motivation, etc.

Mixing alcohol and caffeine is typically not problematic unless one uses extreme amounts of both drugs. Individuals who drink several cups of coffee after using alcohol may experience nausea, jitteriness, sweating, etc.; however, in most instances, this is not going to be a serious issue.

The Development of a Substance Use Disorder and Issues with Polysubstance Abuse

When a person abuses more than one drug on a regular basis, the individual is prone to developing issues with polysubstance abuse. In some cases, individuals who chronically combine different drugs of abuse may accelerate issues with the development of physical dependence on one or both drugs (the development of both tolerance and withdrawal syndromes) and issues that lead to a diagnosis of a substance use disorder.
Polysubstance Abuse
In the latter case, this can include the development of physical dependence as well as issues with:

Controlling use of one or both drugs
Impairment in important areas of functioning, including issues with personal relationships, occupation, school, or other responsibilities
Potentially using drugs in situations where it is dangerous to do so
A failure to fulfill obligations as a result of use of one or both drugs, including issues with parenting, being responsible to others, being responsible at work, etc.

Polysubstance abuse can be particularly complicated to treat for numerous reasons. Clinicians may unintentionally miss or overlook one’s use of alcohol in favor of concentrating on one’s use of some other drug, such as opiates, stimulants, etc. Because individuals in treatment for an alcohol use disorder who have issues with polysubstance abuse need to have all of their issues addressed at the same time, whenever treatment is focused on only one substance of abuse, the treatment outcome will not be successful. Thus, it is essential that all of the issues that occur as a result of an individual’s use of multiple substances be identified and treated. Moreover, as can be gleaned from the information above, chronic polysubstance abuse issues often result in significant issues with emotional, cognitive, and physical functioning compared to the abuse of alcohol alone.

The Effects of Mixing Alcohol & Drugs