We’ve all gone out to drink after popping some ibuprofen or other over-the-counter drugs, and overall we’ve been fine. But what happens when you consistently mix alcohol and prescription, or even over-the-counter, meds? A new study shows that the consequences can be far from safe, and also points out that up to 42 percent of American drinkers have, at some point, mixed booze with pills.

The study, which will be published in the journal Alcoholism: Clinical & Experimental Research, is a national-level report showing that many American adults use a “wide range of prescription medications that can interact with alcohol to cause numerous harms ranging from nausea, headaches, and loss of coordination to internal bleeding, heart problems, and difficulties in breathing,” said study author Rosalind Breslow, an epidemiologist at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), in the press release.

The NIAAA has always warned against mixing alcohol with medication, though no full study has ever shown how many people actually do it. In an online PDF, they list numerous commonly used medications that interact with alcohol in some way, including basic sinus medication like Sudafed and Tylenol. Many times, these meds, when taken with booze, can cause dizziness, drowsiness, stomach bleeding, and other pains.

The researchers wanted to understand the proportion of American adults who mixed alcohol with meds, in order to better target this population to prevent them from doing so and ultimately causing more problems for themselves — or even overdosing. To do so, they examined data on 26,657 adults in the National Health and Nutrition Examination Survey.

Breslow assumed that older people would be the most likely to mix booze with prescription meds, simply because older people are more likely to be on a cocktail of drugs for various aches and pains that happen with age. “People develop more chronic diseases as they age,” Breslow said, “so older people are more likely to be taking medications, many of which can interact harmfully with alcohol. They also may be taking multiple medications to treat multiple diseases. In addition, older people are at a particularly high risk for harmful alcohol-medication interactions.”

She points out that as we get older, our bodies are less able to metabolize alcohol effectively. This is why, at age 20, our hangovers dissipate once we’ve scarfed down an egg sandwich and some caffeine. And why at age 30, we’re unable to get out of bed, becoming too familiar with the hellish two-day hangover. “For instance, diazepam — known as Valium — hangs around in the body about three times longer in a 60-year-old than a 20-year-old, thereby creating a much longer window for potential interactions with alcohol,” Breslow said.

Indeed, older people had the highest prevalence — the proportion of those older than 65 was at 78 percent, compared to the overall adult rate of 42 percent. But among everyone, the most common drugs used included cardiovascular meds like blood pressure drugs, as well as sleeping pills, pain meds, muscle relaxers, metabolic agents for diabetes and cholesterol, and antidepressants.

In short, the authors point out that the potential complications from mixing any type of medicine with alcohol are seemingly endless, simply because alcohol has its own complicated effects on the body, which in turn interact with the drug’s effects, making each scenario a unique cocktail of chemical reactions. “Alcohol can increase blood pressure, which could be counterproductive if one is taking medications to control blood pressure,” said Aaron White, a neuroscientist at NIAAA and an author of the study, in the press release. “Mixing diuretic medications with alcohol, which is also a diuretic, could contribute to dehydration. Mixing alcohol and other sedatives, like sleeping pills or narcotic pain medications, can cause sleepiness, problems with coordination, and potentially suppress brain stem areas tasked with controlling vital reflexes like breathing, heart rate, and gagging to clear the airway.”

Perhaps this large study is the first step in better educating the public about the risks of mixing booze with pills. Though we may be aware of vague potential “risks,” we often disregard them because we assume it will be fine to drink a bit while taking drugs. But learning about the complications is important; read more about what can happen to you if you take certain drugs with alcohol here.

Source: White A, Dong C, Breslow R. Prevalence of Alcohol-Interactive Prescription Medication Use Among Current Drinkers: United States, 1999 to 2010. Alcoholism: Clinical & Experimental Research. 2015.