Clinics sometimes overlook common side effects of medications such as gabapentin, which is frequently prescribed for nerve pain. This can lead to the prescribing of additional drugs that cause new side effects—a phenomenon known as the “prescribing cascade.” It is especially dangerous for older patients.

Gabapentinoids — which include gabapentin (Neurontin) and pregabalin (Lyrica) — can cause swelling in the legs. Doctors may mistake this for heart failure and prescribe diuretics, which in turn can cause kidney problems, dizziness, and falls.

Researchers analyzed medical records of 120 older veterans, mostly men, who had been taking five or more long-term medications. All were taking gabapentinoids, after which they were prescribed loop diuretics to treat suspected fluid buildup, presumably linked to heart failure. The findings were published in JAMA Network Open.

After taking the medications, patients developed swelling in their legs or feet, but only four physicians suspected gabapentinoids as the cause. Sixty-nine doctors considered other diagnoses, including heart failure and venous congestion, a condition in which impaired blood flow increases pressure on the veins. Only one doctor discontinued the medication. Nearly every patient underwent additional testing to rule out serious diseases, and all were prescribed loop diuretics.

Within two months, 28 patients experienced side effects from the new medications: impaired kidney function, dizziness, vision problems, and abnormalities in sodium or potassium levels. Six were hospitalized or sent to the emergency department.

According to researcher Matthew Groudon, in such situations doctors should consider prescribing lower doses or discontinuing the medication to reduce the risk of prescribing cascades and other side effects.

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