Common Painkillers Trick Doctors Into Misdiagnosing Heart Failure, Study Warns

Key Takeaways

• A painkiller could be tricking doctors into misdiagnosing heart failure

• Gabapentinioids cause fluid retention, leading to swelling in the legs and feet

• Many doctors chalked this side effect up to more dire conditions like heart failure

WEDNESDAY, Dec. 3, 2025 (HealthDay News) — A painkiller alternative to opioids could be tricking doctors into misdiagnosing heart failure, a new study warns.

Drugs like gabapentin and pregabalin are frequently prescribed to treat nerve pain, researchers said.

But a side effect of these drugs is fluid retention, causing a person’s legs and feet to swell.

Unfortunately, that's also a well-known symptom of heart failure.

As a result, many patients with this side effect are prescribed unnecessary additional medications like diuretics, increasing their risk of kidney injury, light headedness and injuries from falls, researchers reported Dec. 2 in JAMA Network Open.

“Gabapentinoids are non-opioids, and prescribers associate them with a relatively favorable safety profile,” senior researcher Dr. Michael Steinman, a professor of medicine at the University of California-San Francisco, said in a news release.

“Patients taking them should regularly check in with their doctor to assess whether this is the best treatment for them and consider other options, including non-drug alternatives that might be more appropriate,” Steinman said.

Prescriptions for gabapentenoids have almost doubled in the past decade, as the opioid epidemic sent doctors scrambling for alternative pain relievers, researchers said in background notes.

For the new study, researchers tracked the medical records of 120 veterans with an average age of around 74, all of whom were taking five or more medications long-term.

The veterans had all taken gabapentenoids and developed swelling in their legs and feet. 

However, only four of the veterans’ doctors considered gabapentenoids as a potential cause of the swelling, while 69 chalked the swelling up to other health problems, results show.

Heart failure was the most common alternative explanation provided for patients’ swollen legs and feet, researchers found.

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Another condition doctors cited was venous stasis, in which abnormal blood flow puts pressure on veins, sometimes leading to ulcers.

All of the doctors prescribed diuretics to treat the swelling, including those who suspected gabapentinoids as the cause, researchers said.

Within two months of starting diuretics, nearly 1 out of 4 patients experienced health problems related to those drugs — worsening kidney function, dizziness, blurred vision and low sodium or potassium.

Six patients wound up hospitalized or treated in an emergency room.

Researchers called the use of diuretics an example of “prescribing cascade,” a phenomenon in which more drugs are handed out to treat the side effects caused by earlier prescriptions.

Only one doctor told the patients to stop taking gabapentinoids after they started experiencing swelling in their legs and feet, researchers noted.

On the other hand, close to 1 out of 5 patients underwent medical imaging to rule out life-threatening conditions that could have been causing the swelling, results show.

“Gabapentinoids may be prescribed at unnecessarily high doses or for conditions that they may not help,” lead researcher Dr. Matthew Growdon, an assistant professor of medicine at UCSF, said in a news release.

“In these cases, doctors should consider not prescribing these drugs — or giving lower doses to lessen the risk of prescribing cascades and other side effects,” Growdon said.

More information

The MedShadow Foundation has more on prescription cascade.

SOURCES: University of California-San Francisco, news release, Dec. 2, 2025; JAMA Network Open, Dec. 2, 2025

What This Means For You

People taking gabapentin should be aware that swelling of the feet and legs is a common side effect, and let their doctor know this before starting diuretics.