Gabapentin may not increase risk of falls in older adults with neuropathy or fibromyalgia, finds study

A comparator study using a target trial emulation framework compared the risk for fall-related visits and hospitalizations in the 6 months after initiating gabapentin versus duloxetine among patients with evidence of common conditions for which either medication could be reasonable to use, such as neuropathy or fibromyalgia. The researchers found that compared with duloxetine, gabapentin was not associated with increased fall-related visits during the peri-initiation period. The study is published in Annals of Internal Medicine.

Painful conditions, like neuropathy, significantly increase the risk of falls in older adults, as can the medications used to treat those painful conditions. One of the most common medications used to treat these painful conditions is gabapentin. In 2020, nearly 50 million prescriptions for gabapentin were written, but after several studies highlighted potential safety concerns, 20% fewer gabapentin prescriptions were written in 2022. However, because both gabapentin and the conditions it treats are associated with the same adverse health events, current studies are at risk of incorrectly attributing the health risks associated with the painful conditions themselves to gabapentin. This would mean overestimating the risks of harms gabapentin, which could lead to undertreatment of pain.

Researchers from the University of Michigan, Brigham and Women's Hospital, and Harvard Medical School studied data from 57,086 adults aged 65 years or older with diabetic neuropathy, postherpetic neuralgia, or fibromyalgia who were newly prescribed gabapentin or duloxetine between January 2014 and December 2021. Prior studies have suggested a potential increased risk for falls associated with gabapentin, however, these studies are at risk of bias because they compare users with nonusers. Here, the researchers chose to use a new user, active comparator study design with a target trial emulation framework to more rigorously describe the risk for fall-related injuries and other clinical outcomes in adults receiving gabapentin versus the comparator duloxetine. Participants included in the study met selective criteria to further reduce the risk of confounding.

Notably, these criteria included being age 65 or older, having a diagnosis of postherpetic neuralgia, diabetic neuropathy, or fibromyalgia in the 365 days before cohort entry, and 365 days or more of continuous health plan enrollment before and inclusive of the cohort entry date. Additionally, participants were not allowed to have filled a prescription for either gabapentin or duloxetine in the 365 days before cohort entry, filled a script for both gabapentin and duloxetine at the time of cohort entry, or have active cancer, epilepsy/seizure disorders, or depression/anxiety. The primary outcome was any fall-related visit to an inpatient or outpatient facility. There were three secondary outcomes: a hip fracture–fall event that included a same-day fall-related visit, a fall-related visit to an emergency department and a fall-related hospitalization. Unlike in past work, the researchers did not observe a greater risk for falls with gabapentin use compared to duloxetine use.

According to the authors, patients with pain often report feeling undertreated. This makes accurate risk/benefit estimates for pain medications especially important. These findings should inform conversations between physicians and patients who are considering starting gabapentin.

Reference:

Alexander Chaitoff, Rishi J. Desai, Niteesh K. Choudhry, et al. Assessing the Risk for Falls in Older Adults After Initiating Gabapentin Versus Duloxetine. Ann Intern Med. [Epub 7 January 2025]. doi:10.7326/ANNALS-24-00636.