The pill, spironolactone, costs pennies a day and is most often prescribed as a diuretic to reduce fluid retention in patients with heart failure. The drug works by blocking proteins known as mineralocorticoid receptors, which are located throughout the body and play a role in maintaining a healthy balance of fluids and electrolytes. Some previous lab experiments also suggest that these proteins may play a role in alcohol use. For the new study, researchers tested the effects of spironolactone in mice and rats, then examined medical records for more than two million people who drank alcohol to see if taking the drug was associated with reduced alcohol consumption. Both humans and rodents drank significantly less when they took spironolactone, according to study results published in Molecular Psychiatry. “The available treatments are not effective for all people with alcohol use disorder — one size does not fit all,” says co-senior study author Leandro Vendruscolom, PharmD, PhD, from the National Institute on Drug Abuse (NIDA) in Baltimore. “More medications will help with the treatment of more people with alcohol use disorder.”

There Is a Need for More Drugs to Treat Alcohol Use Disorder

The vast majority of Americans will drink at some point in their lifetime, and roughly 1 in 20 people will develop alcohol use disorder, according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Fewer than 1 in 10 people get any type of treatment. Per the NIAAA, there are currently three drugs approved by the U.S. Food and Drug Administration (FDA) to treat alcohol use disorder: naltrexone, which blocks receptors in the brain that play a role in alcohol cravings and the rewarding sensations from drinking; acamprosate, which helps reduce cravings and withdrawal symptoms when people stop drinking; and disulfiram, which encourages abstinence by causing nausea and other unpleasant symptoms when people drink. “They have only modestly better effects than placebo,” says Henry Kranzler, MD, a professor of psychiatry and director of the Center for Studies of Addiction at the University of Pennsylvania Perelman School of Medicine in Philadelphia, who wasn’t involved in the new study. Another option, the anticonvulsant topiramate, isn’t approved for alcohol use disorder, but doctors sometimes prescribe it “off-label” for this condition, Dr. Kranzler says. While it’s more effective than FDA-approved medications, it also has a wide range of serious side effects and shouldn’t be used with alcohol, notes MedlinePlus. “There is a need for more effective, well-tolerated medications to treat alcohol use disorder,” Kranzler says.

Questions Remain About Drug’s Safety and Effectiveness for AUD

In the new study, male and female mice and rats given spironolactone consumed less alcohol than they did without the drug, and the medication didn’t appear to impact their food or water intake. Higher doses of spironolactone resulted in greater reductions in alcohol consumption. Then, researchers examined medical records from the U.S. Veterans Affairs healthcare system to see if people prescribed spironolactone for its usual purpose — managing heart problems and high blood pressure — drank less alcohol after they started taking the drug. All of the people in the study reported some alcohol consumption. Researchers looked for changes in drinking habits between almost 11,000 people prescribed spironolactone and more than 34,000 people with similar patient profiles who didn’t get prescribed this drug. After an average follow-up period of about 18 months, people taking spironolactone reduced their alcohol consumption significantly more than those who didn’t use this drug. The decrease in drinking was most pronounced among people on the highest doses of spironolactone and among individuals who were heavy drinkers. One limitation of the study is that alcohol use was self-reported by patients, and not independently verified by lab testing. The study also wasn’t designed specifically to test the safety or effectiveness of spironolactone as a treatment for alcohol use disorder. A previous study did examine the effectiveness of spironolactone. This study compared changes in drinking habits over six months among 523 adults prescribed spironolactone and 2,305 adults who didn’t take this drug. The heaviest drinkers reduced their average alcohol intake by more than four drinks a week by the end of the study when they took spironolactone, with the biggest alcohol reductions at higher doses of the drug. Alcohol consumption didn’t appear to change for the heavy drinkers who weren’t prescribed spironolactone. While more research is still needed to verify the effectiveness of spironolactone for alcohol use disorder, research so far suggests that larger clinical trials are warranted, says lead author of this previous study, Vanessa Palzes, MPH, of the Center for Addiction and Mental Health Research at the Kaiser Permanente Northern California Division of Research in Oakland, California. One outstanding question is whether larger human studies will turn up any safety issues when people who take spironolactone also drink alcohol, says Lorenzo Leggio, MD, PhD, co-senior author of the new study and chief of a joint NIDA and NIAA lab in the clinical psychoneuroendocrinology and neuropsychopharmacology section. “Spironolactone has been used in clinical practice for many decades, so its safety, as well as the potential risks and side-effects of this medication, are well-known,” Dr. Leggio says. Common side-effects include:

Lightheadedness and low blood pressureHigh potassium levelsBreast swelling or tenderness

So far, studies examining spironolactone for alcohol use disorder haven’t revealed new side effects or issues that might be unique to people who are heavy drinkers. “However, this question is still important, given that, to our knowledge, there are no formal drug-alcohol interaction studies that have carefully examined the safety of the co-administration of spironolactone and alcohol under well-controlled conditions,” Leggio says. “Such a human study is indeed one of our next steps.”