Long-Term Side Effects of Epidural Steroid Injections

Epidural steroid injections can produce side effects that persist well beyond the procedure itself, ranging from temporary hormonal disruption and bone thinning to rare but devastating neurological injuries. Most people who get a single injection recover without lasting problems, but repeated injections over months or years shift the risk profile considerably. The fact that epidural steroid use has never been formally approved by the FDA for this purpose adds another layer of uncertainty that is worth understanding before agreeing to a series of shots.

How the Steroid Gets Into Your System

The whole point of an epidural steroid injection is to deliver a potent anti-inflammatory directly to the irritated nerve root. But the steroid does not simply stay put. It absorbs into the bloodstream, and once it does, it can affect organs far from your spine. A large trial involving patients with spinal stenosis found that people who received the longer-acting steroid formulations methylprednisolone or triamcinolone experienced roughly a 41% drop in their own cortisol production three weeks after the injection, whereas those who received shorter-acting formulations like dexamethasone did not show the same suppression.1PubMed. Systemic effects of epidural steroid injections for spinal stenosis That cortisol drop is a sign that the steroid is not just acting locally; it is reaching the adrenal glands and telling them to dial back their own output.

This systemic absorption is the root cause of nearly every long-term side effect discussed in this article. The steroid type and dose determine how much gets absorbed and how long the effects linger. Higher doses and longer-acting (particulate) formulations tend to suppress the body’s hormone system more aggressively and for a longer period.

Hormonal Suppression and Adrenal Problems

Your body’s stress-response system, sometimes called the HPA axis, depends on cortisol produced by the adrenal glands. When a large dose of synthetic steroid floods the bloodstream, the brain’s signal to the adrenals weakens. Most people who get an epidural steroid injection experience some degree of this suppression, and most recover within two to four weeks.2Anesthesia and Pain Medicine. Safety of epidural steroids: a review For the majority, the dip is silent and causes no symptoms.

But dose matters. A randomized trial comparing two doses of triamcinolone found that the higher dose (40 mg) suppressed the HPA axis for about 20 days on average, while the lower dose (20 mg) suppressed it for about 8 days, and the higher-dose group was slower to recover.3Pain Physician. Relationship Between Epidural Steroid Dose and Suppression of Hypothalamus-Pituitary-Adrenal Axis When injections are repeated frequently, the adrenal glands may not get enough recovery time between rounds, potentially leading to adrenal insufficiency, a state where the body cannot mount its normal stress response. Case reports describe patients developing full-blown iatrogenic Cushing’s syndrome, with weight gain, moon face, and metabolic disruption, after a series of epidural steroid injections over several months.4PubMed Central. Hypothalamic-Pituitary-Adrenal Suppression and Iatrogenic Cushing’s Syndrome as a Complication of Epidural Steroid Injections

The practical concern here is that if you are getting injections every few weeks or months, you should ask your doctor about timing the next injection to allow adrenal recovery, and you should be aware that sudden withdrawal of steroid input after a long course could leave your body temporarily unable to handle physical stress like illness or surgery.

Bone Loss and Increased Fracture Risk

Corticosteroids are well known for weakening bones over time, and epidural injections are no exception. A systematic review of the available studies found that epidural steroids were linked to significantly decreased bone mineral density in four of the six studies it examined.5PubMed. The Effect of Epidural Steroid Injections on Bone Mineral Density and Vertebral Fracture Risk: A Systematic Review and Critical Appraisal of Current Literature The risk appeared to be dose-dependent: significant bone loss was associated with cumulative methylprednisolone-equivalent doses of 200 mg or more over a year, while lower cumulative doses did not show a clear signal. The same review noted that patients who were already taking anti-osteoporotic medication had lower rates of bone-related problems during their injection course.

A large study of older adults with radiculopathy put the fracture risk in sharper focus. People who received epidural steroid injections had roughly a 39% higher hazard of fracture at typical osteoporotic sites and about a 54% higher hazard of vertebral fracture compared with matched patients who did not get injections. Those who received three or more injections in a single year faced the highest risk, with fractures clustering in the first six months of follow-up.6Journal of Bone and Mineral Research. Epidural steroid injections and fracture incidence among older individuals with radiculopathy

If you are a postmenopausal woman, an older adult, or someone already at risk for osteoporosis, this is one of the most important long-term considerations. You should discuss baseline bone density testing and whether protective medication makes sense if repeated injections are planned.

Blood Sugar Disruption

For people with diabetes, the systemic steroid absorption can cause a sharp, temporary spike in blood glucose. A study of 30 diabetic patients found that average blood glucose jumped from about 160 mg/dL before the injection to roughly 286 mg/dL afterward, an increase of about 126 points. The good news is that the spike had a half-life of about one day, meaning most patients were back to their baseline within two days.7PubMed. Effects of epidural steroid injections on blood glucose levels in patients with diabetes mellitus

A two-day spike sounds short-term, but if you are getting repeated injections, those recurring glucose surges could complicate overall diabetes management. People with poorly controlled diabetes should coordinate closely with both their pain specialist and their diabetes care team around the timing of injections, and should monitor blood sugar more frequently in the days after each procedure.

Rare but Serious Neurological Injuries

The scariest potential outcomes of epidural steroid injections are neurological, and they are genuinely rare. But “rare” does not mean “theoretical.” Two distinct types of lasting neurological damage have been documented.

The first is adhesive arachnoiditis, an inflammatory scarring of the membranes around the spinal cord and nerve roots. Case reports describe patients developing new pain on the opposite side from their original complaint, worsening low back pain, urinary retention, and even motor weakness including foot drop after epidural injections.8PubMed Central. Arachnoiditis following caudal epidural injections for the lumbo-sacral radicular pain The exact mechanism is debated; it may involve chemical irritation from the steroid itself, from preservatives in the injectate, or from infection introduced during the procedure.9PubMed Central. Adhesive arachnoiditis following lumbar epidural steroid injections: a report of two cases and review of the literature Once arachnoiditis develops, it is essentially permanent and difficult to treat.

The second, and arguably more alarming, complication is spinal cord infarction, essentially a stroke of the spinal cord. This happens when the needle or the injected material enters or compresses a critical blood vessel, most commonly the artery of Adamkiewicz. One reported case involved a 55-year-old woman who developed spinal cord infarction after a transforaminal injection at the L2-3 level, with angiography showing that the segmental artery had been occluded by the steroid.10PubMed Central. A case of spinal cord infarction following lumbar transforaminal epidural steroid injection: MR imaging and angiographic findings Particulate steroid formulations (like methylprednisolone and triamcinolone, which do not fully dissolve) are particularly implicated, because suspended particles can physically block small arteries if inadvertently injected into a vessel.11Pain Medicine. Is There a Risk of Neurological Complications Due to Vascular Infarction Associated with Particulate Steroid Use During Interlaminar Epidural Steroid Injections? Non-particulate agents like dexamethasone appear to be a theoretically safer alternative in transforaminal injections for this reason.12PubMed. Comparative effectiveness of cervical transforaminal injections with particulate and nonparticulate corticosteroid preparations for cervical radicular pain

Spinal Infections

Any procedure that punctures the skin near the spine carries some risk of introducing bacteria. Epidural abscesses are uncommon but can have devastating consequences when they do occur. A review of 18 cases of epidural abscess following spinal injections found that symptoms appeared on average about 8 days after the procedure, but the correct diagnosis was not made until about 25 days later. The most commonly identified organism was Staphylococcus aureus. Of those patients, only about a third achieved full recovery, roughly a sixth died, and over a quarter were left with lasting neurological deficits.13PubMed Central. Extensive spinal epidural abscess after nerve root injection in a young non-immunocompromised Patient. Case Report and Literature Review

Case reports also describe subdural abscesses extending along the full length of the spinal canal after a single epidural injection.14PubMed. Spinal subdural abscess following epidural steroid injection The hallmark warning signs are new or worsening back pain, fever, and progressive neurological changes in the weeks after the procedure. Two-thirds of patients in the review had at least one predisposing risk factor such as diabetes or immunosuppression, but infections have occurred in otherwise healthy people as well. Early recognition is critical, because delay in diagnosis tracks directly with worse outcomes.

Less Common Systemic Side Effects

Beyond the major categories above, a range of other side effects have been documented, most of them uncommon but worth knowing about if you are considering repeated injections.

Vaccine response may also be affected. There is suggestive evidence that the immunosuppression from epidural steroids could blunt the body’s response to vaccination, though no study has directly measured the effect of a single injection series on, say, a flu or COVID-19 vaccine.21Korean Journal of Pain. Steroid injections in pain management: influence on coronavirus disease 2019 vaccines If you are scheduling a vaccination, it is reasonable to space it away from a recent injection by at least a couple of weeks, though firm guidelines on timing are still lacking.

The FDA Has Never Approved This Use

It surprises many patients to learn that epidural steroid injections are an off-label use of corticosteroids. In April 2014, the FDA issued a warning stating that injection of corticosteroids into the epidural space may result in rare but serious adverse events including loss of vision, stroke, paralysis, and death, and noted that the safety and effectiveness of corticosteroids for epidural use had not been established.22PubMed. Epidural steroid warning controversy still dogging FDA23JAMA. FDA Warns of Risks Related to Epidural Injections “Off-label” does not mean “illegal” or “fringe”; physicians prescribe medications off-label routinely, and millions of epidural steroid injections are performed each year. But the FDA warning means that there is no regulatory stamp confirming that the benefits outweigh the risks for this specific application. That puts more weight on the informed consent conversation between you and your doctor.

Do You Actually Need the Steroid Part

Here is where the evidence gets genuinely interesting and a little uncomfortable for common practice. Several large analyses have asked whether adding steroid to the injection provides meaningfully better pain relief than injecting local anesthetic alone.

A systematic review examining epidural and facet joint injections found strong evidence that local anesthetic alone was about equally effective as local anesthetic with steroids for most chronic spinal pain conditions. The one exception was disc herniation, where the combination appeared superior.24PubMed Central. Comparison of the efficacy of saline, local anesthetics, and steroids in epidural and facet joint injections for the management of spinal pain: A systematic review of randomized controlled trials A separate meta-analysis covering chronic non-cancer pain injections broadly found that adding steroids to local anesthetic produced a statistically detectable advantage, but the actual difference in pain scores was not clinically meaningful.25PubMed. Addition of corticosteroids to local anaesthetics for chronic non-cancer pain injections: a systematic review and meta-analysis of randomised controlled trials For neck pain specifically, follow-up data at six months, one year, and even two years showed nearly identical improvements in pain and function whether the injection contained lidocaine alone or lidocaine plus steroid.26PubMed Central. Clinical Efficacy of Epidural Injections of Local Anesthetic Alone or Combined with Steroid for Neck Pain: A Systematic Review and Meta-Analysis

This does not mean epidural steroid injections are useless. For acute radiculopathy caused by a fresh disc herniation, the steroid component may provide genuine added benefit. But for many other spinal pain conditions, the steroid is contributing systemic side-effect risk for a questionable marginal gain in pain relief. It is a legitimate question to raise with your provider: would local anesthetic alone be a reasonable first step?

How Injection Technique Changes the Risk Profile

Not all epidural injections carry the same risks. Three main approaches exist: transforaminal (the needle enters through the neural foramen, very close to the nerve root), interlaminar (the needle enters between the vertebral laminae, more centrally), and caudal (the needle enters through the sacral hiatus at the base of the spine). A recent review summarized their trade-offs: the transforaminal approach delivers steroid most precisely to the affected nerve root but carries the highest risk of nerve injury or vascular compromise; the interlaminar approach spreads medication more broadly with lower technical risk but less precision; and the caudal approach is generally the safest trajectory but delivers medication least precisely.27PubMed Central. Understanding the Landscape of Lumbar Epidural Steroid Injections: A Review of Interlaminar, Transforaminal, and Caudal Approaches

The risk of catastrophic vascular injury, including spinal cord infarction, is concentrated almost entirely in the transforaminal approach, because the needle passes close to the segmental arteries that supply the spinal cord. This is why many practitioners now use non-particulate steroids (like dexamethasone) for transforaminal injections, reserving particulate formulations for interlaminar or caudal routes where the vascular risk is lower. If your provider recommends a transforaminal injection, it is worth asking which steroid formulation will be used and why.

Cumulative Dose and Frequency

Most of the serious long-term side effects discussed above are dose-dependent. Bone loss, adrenal suppression, Cushing’s syndrome, and epidural lipomatosis all become more likely with higher cumulative steroid exposure. A review of dosing safety noted that patient selection, steroid type, dose per injection, total number of injections, and interval between injections are all variables that factor into overall risk.28Pain Medicine. Annual Maximum Dose of Epidural Steroid Injection

There is no universally agreed-upon annual maximum dose, but practical guidelines from pain societies generally suggest limiting the total number of injections and spacing them out. The bone density data suggest that staying below a cumulative equivalent of about 200 mg of methylprednisolone per year keeps most patients below the threshold where significant bone loss has been observed.5PubMed. The Effect of Epidural Steroid Injections on Bone Mineral Density and Vertebral Fracture Risk: A Systematic Review and Critical Appraisal of Current Literature The HPA axis data suggest that choosing lower doses and shorter-acting formulations can cut the duration of adrenal suppression roughly in half.3Pain Physician. Relationship Between Epidural Steroid Dose and Suppression of Hypothalamus-Pituitary-Adrenal Axis And the fracture data show that receiving three or more injections in a single year meaningfully elevates risk.6Journal of Bone and Mineral Research. Epidural steroid injections and fracture incidence among older individuals with radiculopathy

If your provider is suggesting a fourth or fifth injection within a year, that is a reasonable moment to pause and have a direct conversation about whether the cumulative steroid burden is justified by the degree of relief you are actually getting.