Bariatric surgery can make your patients more susceptible to the effects of alcohol. Following Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), peak blood alcohol levels may double, according to a recent study published in the International Journal of Obesity.

The findings showed that surgical weight loss patients reached maximum ethanol concentration in half the time it took before surgery.

“This means that, for many patients, one drink after surgery is not physiologically equivalent to one drink before surgery. A practical way to explain it to patients is that the same amount of alcohol may produce at least twice the effect,” Magnus Strømmen, RN, PhD, study author, researcher at the Centre for Obesity Research at St. Olavs Hospital at Trondheim University Hospital, and an associate professor at the Norwegian University of Science and Technology, Trondheim, Norway, told Medscape Medical News in an email.

This was a small prospective, longitudinal, nonrandomized controlled study with 33 adults in Norway who had no history of alcohol use disorder. Ethanol tests were administered before surgery and at 3, 12, and 36 months post-surgery. The findings suggest that bariatric surgery may permanently alter how a patient’s body absorbs and processes ethanol.

While changes were seen after both types of bariatric surgery, the effect was stronger following RYGB. This procedure, compared with SG, led to:

1. 27% higher blood alcohol peak
2. 31% faster time to maximum concentration

“I think the message is not that bariatric surgery should be avoided. Bariatric surgery has substantial benefits for many patients,” Strømmen said. “Rather, our findings show that alcohol risk needs to be taken seriously as part of bariatric care. Patients need clear information before surgery. Clinicians need to consider alcohol-related risk factors much more thoroughly than they do today, and this may also have implications for procedure selection.”

Psych Evals Help Screen Patients at Higher Risk

Clinical practice guidelines recommend that patients undergo psychological evaluations before bariatric surgery to identify any risks and prepare for the major changes ahead. Patients identified as having a history of alcohol use disorder should undergo treatment before bariatric surgery because this could contribute to surgical complications.

Even if patients don’t have this history, discussing the risks is essential. Some bariatric surgery patients use alcohol as an alternative to overeating, and about 8% are at risk of developing new-onset alcohol use disorder after bariatric surgery.

“Your tolerance before surgery is not a reliable indicator of how you will react to alcohol afterward,” Albert Abayev, RD, a clinical dietician with Cedar-Sinai’s Bariatric and General Surgery programs, told Medscape Medical News.

Patients may transfer a compulsive eating addiction to alcohol, drugs, or gambling. As many as 30% of bariatric surgery patients experience this phenomenon, called “addiction transfer,” because they don’t get the same enjoyment from food as they did before the surgery.

“I would discuss it routinely without any judgment before surgery, not only after the problem develops. I would ask the patient about their current alcohol pattern and see if they understand what will change with the bariatric surgery,” Abayev said.

Can GLP-1s Cause Similar Problems?

In recent years, rates of medicated weight loss have risen, whereas bariatric surgery rates have dropped. With the sustained popularity of medications like Wegovy and Zepbound, it is important to consider how patients on these drugs respond to alcohol.

GLP-1s can blunt thirst and contribute to dehydration. Because alcohol also contributes to dehydration, this combination may lead to negative outcomes.

“We do not currently have evidence that weight-loss medicines increase blood alcohol levels in the same way bariatric surgery does. The anatomy is not altered, and these medications generally slow stomach emptying rather than allowing alcohol to reach the intestine more rapidly,” Vance L. Albaugh, MD, PhD, a metabolic and bariatric surgeon and researcher at Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana, and spokesperson for The Obesity Society, told Medscape Medical News in an email.

Some evidence even suggests that semaglutide may reduce alcohol cravings and the number of drinks consumed per day.

“However, this research is still developing. It would be premature to describe GLP-1 medications as established treatments for addiction, but current evidence does not suggest that they create the same alcohol-related risk seen after bariatric surgery,” Albaugh said.

What Your Patients Need to Know

Bariatric surgery is essential for many patients. It is highly effective: 90% of patients lose 50% of their excess body weight and maintain their weight long term, according to the American Society for Metabolic and Bariatric Surgery. This surgery also helps lower all-cause mortality and specific mortality from heart disease, diabetes, and cancer.

However, it is also important to spend time discussing — and following up about — the risks of alcohol problems related to bariatric surgery.

“From a patient standpoint, people don’t appreciate this fully, even though they’re mostly told as they’re going through their pre-op process that this may happen,” Shiara Ortiz-Pujols, MD, MPH, director of Obesity Medicine at Staten Island University Hospital, Northwell health, News York City, told Medscape Medical News.

The new study points out that screening tools like the Alcohol Use Disorders Identification Test may not apply to bariatric surgery patients because this test assumes the respondent will process alcohol normally. It is important to keep this in mind when evaluating a patient’s risk pre- and post-surgery.

When talking to patients, Ortiz-Pujols emphasizes:

• Drinking alcohol may increase dumping syndrome risk. Many bariatric surgery patients experience dumping syndrome, when undigested food travels to the small intestine, causing bloating, diarrhea, confusion, or heart palpitations. “A lot of these alcoholic drinks, especially those that are mixed with sugary mixers, can make the whole situation more magnified,” she said.
• Bariatric surgery may increase the risk for alcohol-related injuries. Research has linked RYGB with an increased risk for alcohol use disorder-related hospitalizations. “They may have previously been able to drink two or three drinks — now, if they have that, it will affect them much more strongly and more quickly,” she said.
• It takes longer to sober up post-bariatric surgery. Patients should know that they may have a greater risk for DUI because their blood alcohol levels can go up more with fewer drinks than they did before surgery, and it takes longer to sober up, she said.

“The levels peak very quickly. For many people, alcohol is often a big part of socializing, work, or otherwise. They need to understand this is real and it happens,” Ortiz-Pujols said.

Abayev, Albaugh, Ortiz-Pujols, and Strømmen reported having no conflicts of interest to disclose.