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New Study Reveals Many Patients at Risk for Dangerous Alcohol-Drug Interactions

Worst Pills, Best Pills Newsletter article July, 2015

Most U.S. adults drink alcohol at least occasionally.[1] Many also take prescription or over-the-counter alcohol-interactive drugs, which are medications that have the potential to interact adversely with alcohol. Combining alcohol with these drugs can seriously affect individual and public health.

A new study published in the February issue of Alcoholism: Clinical and Experimental Research sheds light on the potential scope of this problem. The research, conducted by the National...

Most U.S. adults drink alcohol at least occasionally.[1] Many also take prescription or over-the-counter alcohol-interactive drugs, which are medications that have the potential to interact adversely with alcohol. Combining alcohol with these drugs can seriously affect individual and public health.

A new study published in the February issue of Alcoholism: Clinical and Experimental Research sheds light on the potential scope of this problem. The research, conducted by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), suggests that substantial numbers of adults — particularly those 65 and older — may be putting themselves at risk by consuming alcohol when taking alcohol-interactive prescription drugs.

The NIAAA study highlights the need for patients to protect themselves by understanding the various ways alcohol interacts with many commonly used drugs and by always talking to their physicians or pharmacists before consuming alcohol while taking any drug.

The NIAA study[2]

The study researchers analyzed data on self-reported alcohol consumption and prescription medication use for nearly 27,000 adults ages 20 and older who participated in the National Health and Nutrition Examination Survey from 1999 to 2010. Conducted by the Centers for Disease Control and Prevention using in-person interviews, this large, national survey targets a representative sample of the U.S. population living in the community (as opposed to those living in hospitals, nursing homes or other long-term-care facilities).

The researchers first classified the drinking status of each survey participant as “never,” “former” or “current.” Participants were considered to be current drinkers if they reported consuming at least 12 alcohol-containing drinks during their lifetime and drank at least one day during the past year. Sixty-four percent of adults 20 and older and 47 percent of adults 65 and older were classified as current drinkers.

The NIAAA researchers then examined whether the participants had taken any alcohol- interactive prescription drugs during the previous month. The researchers found that 42 percent of current adult drinkers took at least one alcohol-interactive prescription drug. Among adults 65 and older, 78 percent used such drugs, a finding likely related to the increased use of prescription drugs by the elderly.

Commenting on the importance of their study findings, the investigators emphasized the need for physicians to discuss with patients the risks of dangerous alcohol-drug combinations. They wrote, “A recent report found that only 15.7% of U.S. adults had ever discussed alcohol use with a health professional; among current drinkers, the [rate] was 17.4%.”

How alcohol interacts with medication

Alcohol is itself a drug, and like any drug, it can interact with other medications in several ways. Some medications may interact with alcohol in more than one of the following ways.

A medication may increase blood alcohol levels or the intoxicating effects of alcohol. Several drugs can impair alcohol metabolism (breakdown), thus causing higher blood alcohol levels. For example, three commonly used medications for treating gastrointestinal ulcers and heartburn (see table, page 5) — available both by prescription and over the counter — block the stomach’s ability to metabolize alcohol.[3] Also, the FDA recently warned that the smoking cessation drug varenicline (CHANTIX) can decrease alcohol tolerance (increasing drunkenness) and increase susceptibility to intoxication.[4]

Alcohol may amplify a desired or intended drug effect. One of the best-known alcohol-drug interactions occurs when alcohol, a depressant, is taken with other sedative medications, such as barbiturates, benzodiazepines or nonbenzodiazepine sedative and sleep-inducing drugs.[5] The combination can result in excessive sedation or impaired breathing. Depending on the dose of the sedative and the amount of alcohol, these interactions can be life-threatening or fatal. For instance, people combining alcohol and sedatives can experience falls or other serious accidents, or suffer respiratory arrest.

Alcohol may magnify an adverse drug effect. Alcohol can exacerbate the toxicity of many drugs. For example, nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (ADVIL, IBUPROHM, IBU-TAB, MIDOL LIQUID GELS, MOTRIN IB, PROFEN, TAB-PROFEN) and naproxen (ALEVE, ANAPROX, NAPRELAN, NAPROSYN) increase the risk of gastrointestinal ulcers and bleeding. Alcohol may exacerbate this risk by enhancing the ability of NSAIDs to damage the inner lining of the stomach.[6]

Similarly, both acetaminophen (TYLENOL) and alcohol can damage the liver when used separately, and combining the two magnifies this risk. In particular, alcohol increases the conversion of acetaminophen to a chemical byproduct that is directly toxic to the liver. In people who drink heavily, as little as 2 to 4 grams per day of acetaminophen (equal to four to eight extra-strength pills) can cause liver injury.[7]

A third example is the combination of alcohol with the sleeping drug zolpidem (AMBIEN, EDLUAR, INTERMEZZO, ZOLPIMIST), which can increase the risk of “sleep driving” and other complex behaviors when not fully awake.[8]

Alcohol may increase medication blood levels. Just as many drugs can impair the metabolism of alcohol, so too can alcohol impair the metabolism of many drugs. As a result, consuming alcohol can cause increased blood levels of these drugs, raising the risk of an overdose and adverse drug side effects. For example, consumption of even small amounts of alcohol by a patient who rarely drinks may block the metabolism of the anticoagulant (blood thinner) warfarin (COUMADIN, JANTOVEN).[9] This may cause excessive anticoagulation, increasing the risk of bleeding.

Alcohol may reduce medication blood levels. For other drugs and circumstances (for example, differences in duration of alcohol use), alcohol can accelerate drug metabolism, leading to decreased blood levels of these drugs and inadequate treatment. In many cases, this is more likely to occur in people who chronically ingest moderate to large amounts of alcohol. For example, long-term alcohol consumption can increase the metabolism of warfarin, potentially resulting in inadequate anticoagulation and an increased risk of life-threatening blood clots.[10] Chronic alcohol use also enhances the breakdown of the seizure drug phenytoin (DILANTIN), increasing the risk for seizures.[11]

Alcohol may exacerbate the symptoms of an underlying disease. Alcohol may interact with medications indirectly by adversely affecting the symptoms of the disease for which the medication is being used or by directly changing the effectiveness of drugs being used to treat the disease. For example, excessive alcohol use can be detrimental for patients with psychiatric disorders such as depression, bipolar disorder and schizophrenia and also may reduce the effectiveness of medications used to treat these disorders. Other diseases adversely affected by alcohol include hypertension, diabetes, upper gastrointestinal conditions, gout, insomnia and cognitive impairment, such as Alzheimer’s disease.

For additional examples of important alcohol-medication interactions, see the table below.

Many of the same factors that make older people more susceptible to adverse drug reactions also make them more likely to experience harmful alcohol-drug interactions. For example, because of age-related decreases in liver function, older people break down alcohol (and many drugs) more slowly. Second, because older adults generally weigh less and have a smaller amount of total body water and a higher proportion of body fat than younger people, they achieve higher blood alcohol levels per amount of alcohol consumed. Older people also use significantly more drugs, on average, than younger people, increasing the likelihood of harmful alcohol-drug interactions.

What You Can Do

With reasonable precautions and common sense, it is possible to substantially reduce the risk of alcohol-medication interactions. The easiest and best way to avoid the problem is simply to abstain from drinking alcohol while you are taking medications, especially if the use of the medication is short-term.

Sometimes people are unaware of a warning against using alcohol until they already have taken a medication for a week or two, and they have seen no problems with their glass of wine at dinner. This may cause them to wonder if the alcohol warning is overkill. The truth is that for most medications, a limited amount of alcohol, such as a small glass of wine with dinner, is not likely to cause problems.

It is better to be safe than sorry, however, so if you are considering drinking alcohol while taking medications, you should follow these guidelines:

  • Always check with your prescribing health care professional or pharmacist before taking alcohol with any prescription or over-the-counter drug.
  • Read all the information you receive from your health care professional or pharmacist about your prescription medications. If alcohol is a problem, it will usually be mentioned.
  • Read the warning labels on the medication bottle or package. If it says not to drink alcohol, don’t. But the absence of an alcohol warning sticker on the bottle is not an absolute guarantee that it is safe to drink alcohol.

Examples of Drugs That Interact With Alcohol

Drug class or drug* Potential interaction
acetaminophen (TYLENOL)
  • Alcohol increases risk of liver damage due to increased formation of chemical byproduct of acetaminophen that is directly toxic to the liver.
  • griseofulvin (GRIS-PEG, GRIVULVIN V), metronidazole (FLAGYL; PYLERA)**
  • Griseofulvin and metronidazole can cause flushing, nausea, vomiting and headache with alcohol use.
  • Chronic ingestion of excessive amounts of alcohol may reduce doxycycline blood levels.
  • Alcohol increases the risk of isoniazid-induced liver disease.
  • warfarin (COUMADIN, JANTOVEN)
  • Acute alcohol intake may increase warfarin levels, causing excessive anticoagulation, increasing the risk of bleeding.
  • Chronic alcohol intake may decrease warfarin levels, leading to inadequate anticoagulation and increasing the risk of blood clots.
Antidepressants, tricyclic
  • amitriptyline,*** doxepin (SILENOR, ZONALON),*** nortriptyline (PAMELOR)**
  • Alcohol increases the risk of sedation and of orthostatic hypotension (sudden drop in blood pressure upon standing).
  • Alcohol itself can worsen depression, potentially rendering any antidepressant less effective.
Antihistamines, sedating
  • cetirizine (XYZAL, ZYRTEC),** diphenhydramine, hydroxyzine (VISTARIL)
  • Alcohol increases the risk of sedation, particularly in the elderly; especially dangerous with driving and other tasks requiring alertness.
Anti-seizure drugs
  • phenytoin (DILANTIN)
  • Acute alcohol intake may increase phenytoin levels, increasing the risk of drug toxicity.
  • Chronic alcohol intake may decrease phenytoin levels, leading to inadequate seizure control.
Diabetes drugs
  • chlorpropamide (DIABINESE),*** glyburide (DIABETA, GLUCOVANCE, GLYNASE),** tolbutamide**
  • Excessive alcohol consumption may result in hypoglycemia (low blood sugar) when combined with many diabetes drugs.
  • The three listed drugs can cause flushing, nausea, vomiting and headache if alcohol is consumed.
Histamine H2 receptor blockers (for ulcers and heartburn)
  • cimetidine (TAGAMET), nizatidine (AXID), ranitidine (ZANTAC)
  • Excessive alcohol intake may worsen ulcers.
  • The three listed drugs can block alcohol metabolism by the stomach, increasing blood alcohol levels.
High blood pressure drugs
  • Angiotensin-converting enzyme inhibitors
  • Angiotensin receptor blockers
  • Beta blockers
  • Calcium channel blockers
  • Others: clonidine (CATAPRES, CLORPRES, KAPVAY),**** doxazosin (CARDURA),**** hydralazine** (BIDIL, HYDRA-ZIDE), methyldopa, prazosin (MINIPRESS),*** terazosin****
  • Alcohol may increase the risk of dangerous hypotension (low blood pressure).
  • Alcohol can increase the sedative effects of clonidine.
Nonsteroidal anti-inflammatory drugs
  • celecoxib (CELEBREX),*** ibuprofen (ADVIL, CALDOLOR, IBUPROHM, IBU-TAB, TAB-PROFEN), indomethacin (INDOCIN, TIVORBEX),*** naproxen (ALEVE, ANAPROX, NAPROSYN)
  • Alcohol increases the risk of gastritis (inflammation of the inner lining of the stomach) and gastrointestinal ulcers and bleeding.
Opioid analgesics
  • Alcohol increases the risk of sedation and depressed or impaired breathing, which can be life-threatening; especially dangerous with driving and other tasks requiring alertness.
Sedatives, hypnotics, sleeping medications, tranquilizers
  • Benzodiazepines: alprazolam (XANAX),*** diazepam (DIASTAT, VALIUM),*** lorazepam (ATIVAN)***
  • Nonbenzodiazepine sleeping drugs: eszopiclone (LUNESTA),*** suvorexant (BELSOMRA),*** zolpidem (AMBIEN, EDLUAR, INTERMEZZO, ZOLPIMIST)***
  • Alcohol increases the risk of sedation/sleepiness; especially dangerous with driving and other tasks requiring alertness.
Smoking cessation drugs
  • varenicline (CHANTIX)**
  • Varenicline can cause decreased alcohol tolerance and increased susceptibility to intoxication.

*The list of drug classes, as well as the lists of specific drugs, that interact with alcohol are not exhaustive.
**Limited Use
*** Do Not Use
**** Do Not Use for high blood pressure; doxazosin and terazosin are Limited Use for prostate enlargement.



[1] Public Citizen. Letter to FDA on the off-label promotion of several diabetes drugs. March 31, 2015. http://www.citizen.org/documents/2250.pdf. Accessed April 21, 2015.

[2] Breslow RA, Dong C, White A. Prevalence of alcohol-interactive prescription medication use among current drinkers: United States, 1999 to 2010. Alcohol Clin Exp Res. 2015;39(2):371-379.

[3] Weathermon R, Crabb DW. Alcohol and medication interactions. Alcohol Res Health. 1999;23(1):40-54.

[4] Food and Drug Administration. FDA Drug Safety Communication: FDA updates label for stop smoking drug Chantix (varenicline) to include potential alcohol interaction, rare risk of seizures, and studies of side effects on mood, behavior, or thinking. March 9, 2015. http://www.fda.gov/Drugs/DrugSafety/ucm436494.htm?source=govdelivery&utm_medium=email&utm_source=govdelivery. Accessed April 21, 2015.

[5] Weathermon R, Crabb DW. Alcohol and medication interactions. Alcohol Res Health. 1999;23(1):40-54.

[6] Weathermon R, Crabb DW. Alcohol and medication interactions. Alcohol Res Health. 1999;23(1):40-54.

[7] Ibid.

[8] Sanofi-aventis. Drug label for AMBIEN – zolpidem tartrate tablet, film coated. Revised October 2014. http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c36cadf4-65a4-4466-b409-c82020b42452. Accessed April 21, 2015.

[9] Ibid.

[10] Ibid.

[11] Ibid.