Gabapentin Side Effects: What Are The Uses and Long-Term Risks?

Gabapentin side effects range from common drowsiness and dizziness to serious risks like respiratory depression and withdrawal seizures. Studies show that combining gabapentin with opioids is associated with about a 50% higher risk of opioid-related death, making context everything. This article walks through what gabapentin is approved for, what side effects to expect, which ones are most serious, and what happens when you stop taking it.

Gabapentin Side Effects and What They Mean

Gabapentin is FDA-approved for two main uses: managing postherpetic neuralgia in adults and as add-on therapy for partial-onset seizures in adults and children aged 3 and older. It is also widely prescribed off-label for other neuropathic pain, anxiety, insomnia, and fibromyalgia, though the evidence for many of those uses is mixed.

The drug works by binding to a subunit of voltage-gated calcium channels in the brain, which reduces overactive nerve signaling. That mechanism explains both its benefits and its most common side effects. When you dampen neuronal activity, you also slow down alertness, balance, and coordination.

Common Side Effects of Gabapentin

Most people who take gabapentin notice some combination of the following, especially when starting or increasing the dose:

• Drowsiness and fatigue
• Dizziness or lightheadedness
• Unsteadiness, poor coordination, or ataxia
• Blurred or double vision
• Swelling in the legs or feet
• Weight gain
• Nausea, diarrhea, or constipation
• Memory problems or slowed thinking
• Slurred speech

These effects are often dose-related and may ease over time. But they are not trivial. The FDA label specifically warns patients not to drive or operate complex machinery until they know how gabapentin affects them, because impairment can be subtle and patients may underestimate it.

In older adults, dizziness and unsteadiness are not just inconvenient. They can lead to falls, fractures, and hospitalization. A population-based cohort study of older adults with chronic kidney disease found that starting a higher gabapentin dose was associated with a greater 30-day risk of hospital visits for encephalopathy, falls, and fractures compared with lower-dose initiation.

What Are the Most Serious Side Effects of Gabapentin?

The serious side effects of gabapentin fall into several categories. Each one requires a different response.

Respiratory depression is now one of the most important safety concerns. The FDA required new warnings for gabapentinoids in 2019 after serious breathing difficulties were reported in patients using gabapentin alongside opioids, other sedatives, or with underlying lung disease. The UK’s MHRA warned that severe respiratory depression can occur even without opioids, particularly in older adults, people with kidney disease, and those with respiratory conditions, estimating the post-marketing frequency at up to 1 in 1,000 patients.

DRESS and severe allergic reactions are rare but life-threatening. DRESS stands for Drug Reaction with Eosinophilia and Systemic Symptoms, a multiorgan hypersensitivity reaction. The Medication Guide lists symptoms including rash, hives, fever, swollen glands, yellowing of the skin or eyes, unusual bruising, and frequent infections. Angioedema, which is swelling of the face, lips, tongue, or throat, and anaphylaxis are also possible. These are not “wait and see” situations. They need immediate medical attention.

Suicidal thoughts and behavior carry a class warning for all antiepileptic drugs. The Medication Guide states that gabapentin may cause suicidal thoughts or actions in about 1 in 500 people. Patients and caregivers should watch for new or worsening depression, agitation, panic attacks, unusual mood changes, or any thoughts of self-harm, especially during the first weeks of treatment, after dose changes, and after stopping.

Overdose toxicity can produce double vision, tremor, slurred speech, severe drowsiness, altered mental status, and diarrhea. Fatal respiratory depression has been reported with gabapentin overdose, both alone and in combination with other CNS depressants. Gabapentin can be removed by hemodialysis. If you suspect an overdose, call Poison Control at 1-800-222-1222.

Long-Term Side Effects of Gabapentin

Long-term gabapentin use carries risks that are often underestimated, partly because the drug is not federally scheduled and is not an opioid. But “not an opioid” does not mean “no long-term risk.”

Physical Dependence and Withdrawal

One of the clearest long-term risks is physical dependence. The nervous system adapts to gabapentin’s presence, and when the dose drops or stops, it can react. A 2016 systematic review identified 18 case reports involving gabapentin addiction or withdrawal. In addiction cases, all patients had prior histories of alcohol, cocaine, or opioid misuse. Average doses in those cases exceeded 3,000 mg per day. Misuse prevalence was about 1% in the general population but as high as 22% in drug treatment center populations, showing that risk is not evenly spread.

Dependence can develop even at lower doses. Documented withdrawal has occurred in people taking as little as 400 to 800 mg per day for as few as three weeks. The longer the use, the higher the dose, and the more risk factors present, the more carefully stopping needs to be managed.

Sedation, Cognitive Slowing, and Falls Over Time

Drowsiness and dizziness that seem manageable at first can become more consequential over months or years, especially as kidney function declines with age. Because gabapentin is cleared almost entirely by the kidneys, a dose that was safe at age 55 may accumulate to toxic levels at age 70 if kidney function has dropped. The FDA label states that older adults are more likely to have decreased renal function and require dose adjustment based on creatinine clearance.

In hospitalized adults with chronic kidney disease, a 2025 study found that gabapentinoid use was associated with significantly higher respiratory depression risk, with an odds ratio of 1.71. The dose-response relationship was striking: respiratory depression occurred in about 83% of patients receiving gabapentin above 1,400 mg per day, compared with about 30% at lower doses.

Opioid Combination: The Central Long-Term Risk

The most dangerous long-term scenario is combining gabapentin with opioids. A large population-based study found that co-prescribing gabapentin with opioids was associated with a 50% higher risk of opioid-related death. Very high gabapentin doses alongside opioids were associated with nearly double the risk. A 2022 systematic review similarly found that combination therapy was associated with increased dizziness, cognitive dysfunction, respiratory depression, and mortality signals compared with opioid therapy alone.

This matters for long-term use because many patients receive both medications for chronic pain. The combination may be intended to reduce opioid reliance, but the evidence shows it can increase the risk of fatal overdose.

Mood and Suicidality During Long-Term Use

The suicidality warning does not only apply to the first weeks of treatment. Newer labeling notes that suicidal thoughts and behavior have been reported both during gabapentin use and after stopping it. Long-term prescribing in patients with chronic pain, insomnia, anxiety, or depression requires ongoing mood monitoring, not just at initiation.

Side Effects of Stopping Gabapentin

Stopping gabapentin, especially after long-term or high-dose use, can produce a withdrawal syndrome. The FDA label advises tapering over at least one week, with longer tapers at the prescriber’s discretion. But case reports show that one week is not enough for everyone.

What Withdrawal Feels Like

Withdrawal symptoms typically begin within 12 hours to 7 days after stopping or significantly reducing the dose. Common symptoms include:

• Anxiety, agitation, and restlessness
• Insomnia
• Nausea, vomiting, or diarrhea
• Sweating and tremor
• Headache and dizziness
• Body aches and flu-like symptoms
• Mood swings or depression
• Rebound nerve pain
• Confusion or disorientation

Most cases resolve within 5 to 10 days. But some patients, particularly those with long-term high-dose use, older age, kidney disease, psychiatric conditions, or substance use histories, may experience symptoms for weeks or months.

Serious Stopping Risks

The most serious risk of stopping gabapentin abruptly is seizure. In people taking gabapentin for epilepsy, sudden discontinuation can trigger status epilepticus, a prolonged seizure that will not stop on its own. This is a medical emergency. Even in people not taking gabapentin for seizures, abrupt cessation can lower the seizure threshold.

Other serious stopping effects include severe confusion, hallucinations, psychotic symptoms, suicidal ideation, and autonomic instability. These require immediate medical attention.

A case report published in a peer-reviewed journal described an 81-year-old woman who had taken gabapentin for five years and developed debilitating withdrawal symptoms after a week-long taper. Her symptoms worsened over 10 days and only improved after gabapentin was reintroduced. Another case involved a 32-year-old woman whose taper took 18 months to complete safely.

How to Stop Gabapentin Safely

The safest approach is a gradual, individualized taper guided by a clinician. Key principles include:

• Never stop suddenly after regular use
• Reduce the dose slowly, pausing if withdrawal symptoms become severe
• Adjust the taper speed based on dose, duration, kidney function, age, and psychiatric history
• Monitor for mood changes, seizures, pain flares, and breathing problems
• Have a plan for what to do if symptoms escalate

NICE guidance classifies gabapentinoids as medicines associated with dependence or withdrawal and recommends individualized, patient-centered withdrawal management. Regional NHS guidance similarly discourages abrupt cessation and supports structured deprescribing reviews every 3 to 6 months.

Why Gabapentin Risk Is Context-Dependent

Gabapentin is not equally risky for everyone. The evidence consistently shows that serious harm clusters around predictable vulnerabilities.

Patients at higher risk include older adults with declining kidney function, people taking opioids or benzodiazepines, those with chronic lung disease or sleep apnea, people with substance use histories, and anyone on high doses without regular reassessment. For these groups, what looks like a routine prescription can become a serious safety problem over time.

For patients with normal kidney function, no respiratory disease, no sedative co-medications, and a clear indication, gabapentin is often well tolerated. The drug remains valuable for postherpetic neuralgia and adjunctive seizure treatment. The problem is not gabapentin itself. It is gabapentin used indefinitely, at escalating doses, without monitoring, in people who face compounding risks.

StatPearls clinical guidance recommends checking baseline creatinine before and during treatment and actively screening for depression, behavioral changes, and suicidality throughout therapy. These are not optional extras. They are the minimum standard for safe prescribing.

If you or someone you care about is struggling with gabapentin dependence, withdrawal, or a co-occurring substance use concern, speaking with a specialist is the right next step. Reach out to the team at Thoroughbred Wellness and Recovery to explore medical detox options and get the support you need.