Does Gabapentin Cause Bone Loss? What the Science Says

Gabapentin has not been definitively proven to cause bone loss in humans, but a growing body of evidence suggests it raises fracture risk through at least two pathways: increased falls from side effects like dizziness and drowsiness, and possible direct interference with bone biology through its action on calcium channels. The picture is genuinely unsettled, with older reviews classifying gabapentin as one of the safer seizure medications for bone health and newer, larger studies raising more serious concerns. How much of the fracture signal comes from falling and how much from weakened bone remains one of the open questions in this area.

What Large Human Studies Show About Fracture Risk

The strongest evidence linking gabapentin to broken bones comes from several large observational studies, and the results are hard to ignore even if they don’t prove causation outright. A study of more than 571,000 US veterans found that gabapentin users had a roughly 35 percent higher rate of falls or fractures compared to non-users, and there was a clear dose-response pattern: the highest-dose group (at or above 2,400 mg per day) had about 90 percent higher risk.¹ That dose-response relationship matters because it suggests the link isn’t just a coincidence of sicker patients being prescribed gabapentin.

A 2024 study published in JAMA Network Open focused specifically on hip fractures in people who had been dispensed a gabapentinoid (gabapentin or pregabalin). After adjusting for other central nervous system medications and time trends, gabapentinoid use was still associated with about 30 percent higher odds of hip fracture. In people with chronic kidney disease, the odds roughly doubled and a half, with an adjusted odds ratio near 2.4.² Hip fractures are particularly concerning because they carry serious consequences in older adults, including loss of independence and increased mortality.

A separate study looked specifically at patients with inflammatory arthritis, a population already at elevated fracture risk. Among these patients, current gabapentinoid users had about 36 percent higher odds of any fracture compared to those who had used the drug in the more distant past. The associations were similar for gabapentin alone (about 38 percent higher) and pregabalin alone (about 40 percent higher), and the risk was strongest in people who had started the medication more recently.³

One important caveat runs through all of these: they are observational. People prescribed gabapentin tend to have chronic pain, neuropathy, or other conditions that themselves raise fall and fracture risk. Researchers try to control for this “confounding by indication,” but they cannot fully eliminate it. The inflammatory arthritis study tried to get around this by comparing current gabapentinoid users only to past users of the same drug, so everyone in the study had at some point been prescribed a gabapentinoid. That the signal still showed up is noteworthy, though it does not settle the question completely.

Older Evidence That Seemed More Reassuring

Part of the reason gabapentin has not traditionally been flagged as a bone-harming drug is that earlier research grouped it with the “safer” seizure medications. A Danish case-control study of more than 7,500 patients on anticonvulsants found that fracture risk was higher with enzyme-inducing drugs like carbamazepine and phenytoin, but not with gabapentin or other non-enzyme-inducing drugs.⁴ Reviews from around the same era described the data on gabapentin’s bone effects as limited and inconclusive.⁵

The newer, larger studies have shifted the conversation. One likely explanation for the discrepancy is that gabapentin prescribing has exploded since those earlier studies were done. It is now widely used not just for epilepsy but for nerve pain, fibromyalgia, restless leg syndrome, and sometimes off-label for anxiety and insomnia. With millions more people on the drug, often at higher doses and for longer durations, effects that were hard to detect in smaller epilepsy-focused cohorts have become more visible.

How Gabapentin Might Affect Bone Directly

Gabapentin works by binding to a specific part of voltage-sensitive calcium channels called the α2δ1 subunit. That binding is what makes it useful for controlling nerve pain and seizures: it dials down excitatory signaling between nerve cells. But bone cells, muscle cells, and cartilage cells also express that same subunit, and calcium signaling in those tissues plays important roles in bone formation, sensing mechanical stress, and tissue repair.⁶ So in theory, gabapentin could be muting calcium-dependent processes that bones need to stay healthy.

The JAMA Network Open hip fracture study noted that while most of the short-term fracture risk from gabapentinoids likely comes from falls triggered by dizziness and drowsiness (which tend to peak in the first couple of weeks on the drug), the medications may also have longer-term effects on bone health through this interference with calcium balance.² If true, that would mean the fracture risk does not simply go away once you adjust to the drug’s sedating effects.

Lab work on human bone cells adds some texture. When researchers exposed human bone-forming cells (osteoblasts) and bone-resorbing cells (osteoclasts) to gabapentin directly, both cell types showed reduced development.⁷ On the surface, suppressing both sounds like it might cancel out, but bones need a careful balance between formation and resorption. Disrupting both processes does not necessarily leave the net balance unchanged, and in a living person the context matters: age, hormonal status, physical activity, and nutritional status all shift which side of that equation dominates.

Conflicting Animal Evidence

Animal studies, which allow researchers to isolate the drug effect from confounders like chronic illness, have produced mixed results. One study in rats given gabapentin at 150 mg/kg found clear bone damage: reduced bone volume, wider spacing between the tiny struts of spongy bone, less new bone being laid down, and more bone being broken down by resorption cells.⁸ These findings suggested that gabapentin could thin out the interior lattice of bone, the kind of damage that eventually leads to fractures in humans.

But another rat study specifically designed to measure bone density and strength found no significant changes in either measure after gabapentin exposure, including in rats that had been castrated to mimic a low-hormone state similar to postmenopausal osteoporosis.⁹ The difference may come down to doses used, duration of exposure, which bone parameters were measured, or the specific strain of rat, but it illustrates why researchers have not reached a firm consensus. Some animal work says gabapentin harms bone; other animal work says it does not.

Falls, Sedation, and the Two-Pathway Problem

One of the trickiest parts of interpreting the human data is that gabapentin raises fracture risk through at least two separate routes. The first and best-documented route is falls. Gabapentin commonly causes dizziness, drowsiness, and coordination problems, especially when you first start it or increase the dose. These side effects are most pronounced in the first week or two but can persist in some people. A higher dose means more sedation and more falls, which is consistent with the dose-response pattern seen in the veterans study.

The second possible route is the direct bone-weakening pathway described above. The challenge for researchers is that both pathways lead to the same outcome (fractures), so it is difficult to separate their contributions in human studies. You cannot easily measure whether a hip fracture happened because the bone was weaker or because the person fell harder or more often. The animal studies that show bone changes without falls suggest at least some of the problem is in the bone itself, but as we saw, those animal results are not unanimous.

For you as a patient, the practical upshot is the same regardless of which pathway dominates: the fracture risk appears real and increases with dose. Whether it is your bones getting thinner, your balance getting worse, or some combination, the actions you’d want to take are similar.

Who Faces the Highest Risk

The studies consistently identify certain groups who appear especially vulnerable to gabapentin-related fractures:

• Older adults: In the hip fracture study, roughly 60 percent of cases were in people over 80, and more than 70 percent were women. Older adults already have thinner bones and are more prone to falls, so gabapentin’s effects on both pathways land harder.
• People with kidney disease: Gabapentin is eliminated almost entirely by the kidneys. When kidney function declines, the drug accumulates to higher blood levels, amplifying both the sedation and any direct bone effects. The hip fracture study found that people with chronic kidney disease on gabapentinoids had more than double the fracture odds of those without kidney problems.²
• People with inflammatory arthritis: This population already has elevated fracture risk from the disease itself and from treatments like corticosteroids. Adding a gabapentinoid pushed fracture odds up by about a third on top of that baseline.³
• People taking other sedating medications: Combining gabapentin with opioids, benzodiazepines, or other central nervous system depressants compounds the fall risk. The JAMA study specifically adjusted for this and still found elevated fracture odds, but the raw numbers were worse when other sedating drugs were in the mix.

Interestingly, in the veterans study, certain high-risk populations like those with alcohol use disorder, HIV, or hepatitis C had elevated fall and fracture rates regardless of gabapentin exposure, and gabapentin did not appear to add further risk on top of what those conditions already caused.¹ This could mean the signal was washed out by high baseline rates, or it could hint that gabapentin’s contribution matters most when a person’s background risk is moderate rather than already very high.

How Gabapentin Compares to Other Seizure Drugs

Seizure medications have long been associated with bone problems, but not all of them carry equal risk. The drugs most clearly linked to bone loss are the older, enzyme-inducing medications like phenytoin, phenobarbital, and carbamazepine. These drugs ramp up liver enzymes that break down vitamin D, leading to lower calcium absorption and weaker bones over time. That mechanism is well established and has been documented for decades.

Gabapentin does not induce liver enzymes and does not reduce vitamin D levels through that pathway. This is why earlier reviews considered it relatively bone-safe among seizure drugs.⁵ The emerging concern is that gabapentin may harm bone through a completely different mechanism, namely its action on calcium channels, which would not have been caught by studies focused on the vitamin D pathway. The lesson here is that “no enzyme induction” does not automatically mean “bone-safe.”

Pregabalin, gabapentin’s close cousin that works on the same calcium channel target, consistently shows up with similar or slightly higher fracture associations in the studies that examine both drugs.³ This parallelism is suggestive because it points to the shared mechanism rather than some unrelated property of gabapentin alone.

What This Means If You Are Healing a Fracture

A separate but related question is whether gabapentin affects how well bones heal after a break. This matters practically because gabapentin is commonly prescribed for post-surgical and post-injury pain management. Two animal studies have looked at this directly, and both raise concerns.

In one rat study, high-dose gabapentin significantly reduced the volume of new bone forming at a fracture site by the second week, and that deficit persisted at four weeks.¹⁰ In another, fractures in rats given gabapentin showed slower healing on tissue analysis and weaker callus strength at 30 days compared to controls. The researchers concluded that gabapentin negatively affected the fracture healing process.¹¹

These are animal findings, and it would be premature to say gabapentin definitely slows fracture healing in humans. But given that the drug is frequently prescribed for pain after orthopedic surgery or fracture, the possibility is worth paying attention to. Some orthopedic researchers have begun suggesting that alternatives should at least be considered when managing pain in a patient whose fracture needs to heal.

Practical Considerations for People Taking Gabapentin

If you are on gabapentin and worried about bone health, a few practical points stand out from the evidence:

• Dose matters: The fracture risk appears dose-dependent. If you are on a high dose and your prescriber can reduce it without losing pain control, that may lower your risk. This is a conversation to have with your doctor, not a change to make on your own.
• Kidney function matters: If you have reduced kidney function, gabapentin lingers in your body at higher levels than intended. Dose adjustments for kidney function are standard practice, but it is worth confirming yours has been made, especially if your kidney function has changed since the drug was first prescribed.
• Fall prevention helps regardless: Whether gabapentin weakens bone directly or raises fracture risk mainly through falls, reducing your fall risk is protective. That means removing tripping hazards at home, using good lighting, wearing supportive shoes, and being cautious when getting up from bed or a chair, especially during the first few weeks on the drug or after a dose increase.
• Bone density screening: If you are in a high-risk group (postmenopausal, over 65, on corticosteroids, or have a condition that already raises fracture risk), asking about a bone density scan is reasonable. It gives you a baseline and helps your doctor weigh the benefit of gabapentin against your personal fracture risk.

Standard bone-protective measures like adequate calcium and vitamin D intake, weight-bearing exercise, and not smoking apply to everyone but may be especially worth attending to if you are on long-term gabapentin. These steps won’t fully counteract a drug-related bone effect, but they keep you from compounding the risk with preventable deficiencies.

Why the Science Remains Unsettled

The honest state of the evidence is that gabapentin probably increases fracture risk, but the relative contributions of falls and direct bone effects are unclear, and the direct bone evidence is still largely preclinical. No large randomized trial has been designed to measure gabapentin’s effect on bone density in humans over time, and it is unlikely one ever will be, both because the drug is generic (removing the financial incentive for a manufacturer to fund such a study) and because it would be ethically complicated to randomize people to a drug suspected of causing harm. That leaves us relying on observational data, which can show associations but always leaves room for the possibility that confounding explains some or all of the signal.

The calcium-channel mechanism is biologically plausible and has support from cell and animal studies, but two animal studies looking directly at bone density in living rats disagree with each other. The human cell study showing suppression of both bone-forming and bone-resorbing cells does not translate straightforwardly into a prediction about what will happen in a whole person over months or years. It is the kind of evidence that justifies concern and further investigation, not the kind that justifies panic.

What makes the newer studies meaningful is their size and their attention to confounding. A cohort of half a million veterans with dose-response data and consistent signals across subgroups carries more weight than older studies of a few thousand patients that found no effect. The field has moved from “gabapentin looks safe for bone” to “gabapentin raises fracture risk, and the mechanism may include direct bone effects.” It has not yet arrived at “gabapentin causes bone loss,” at least not with the certainty that phrase implies. For most people on the drug, the practical response is the same either way: stay on the lowest effective dose, take fall precautions seriously, and keep your prescriber informed about any bone health concerns.