Taking too much gabapentin on its own usually makes a person very sleepy, dizzy and wobbly rather than putting their life at risk, and most people recover within hours. How dangerous an extra dose is depends less on the amount than on what else is in the body, especially opioids and other sedating drugs, and on how well the kidneys work. The same amount that leaves one person drowsy can seriously harm someone who takes opioids or has kidney failure.
Symptoms of a Gabapentin Overdose and How Long They Last
The most common effects of too much gabapentin are drowsiness, dizziness, unsteady walking, nausea, vomiting, a fast heartbeat and low blood pressure.1Poison Control. Neurontin (gabapentin): Side effects, interactions, and overdose | Poison Control Some people also notice blurred or double vision, tiredness and diarrhea after a large amount. Others feel nothing at all: in one group of overdose cases handled at home, four of seven had no symptoms.2PubMed. Characterization of gabapentin overdose using a poison center case series
When gabapentin is the only drug involved, symptoms tend to appear early and, in most people, are gone within about 10 hours.3PubMed. Characterization of gabapentin overdose using a poison center case series In one set of 20 cases where gabapentin was the only drug taken, with amounts from 50 mg up to 35 grams, none of the people needed to be admitted to hospital.4PubMed. Characterization of gabapentin overdose using a poison center case series One reason is that the body absorbs less and less of each extra dose as the amount rises, which limits how high blood levels climb.5Journal of Pharmaceutical and Biomedical Analysis. Bioavailability of gabapentin assessed by cumulative urine sampling compared with a model for the saturated absorption of gabapentin In rare severe cases, extreme lethargy, coma and death can occur, usually with other substances involved.6Poison Control. Neurontin (gabapentin): Side effects, interactions, and overdose | Poison Control
An accidental double dose usually looks modest. Someone who takes their evening dose twice may feel heavy, sleepy and off balance within an hour or two. Most people feel back to normal by the next morning. Don’t skip or change doses to balance things out; just resume your normal schedule.
A single extra capsule or tablet is a much smaller event than the large amounts in that case series, and for most people it brings mild sleepiness or none at all. How strongly you react also depends on how long you have been taking gabapentin. People who take it daily have often built some tolerance to the drowsiness, while someone who just started, or just raised the dose, is more likely to feel an extra dose strongly.
Effects can build over the first few hours as the drug is absorbed, so feeling fine early doesn’t mean nothing happened. Drowsiness that keeps deepening instead of easing is a reason to get help.
The most common way a gabapentin overdose actually hurts someone is an injury from dizziness or poor coordination, not the drug itself. Bathrooms and stairs are the highest-risk places, so a person who feels wobbly should sit or lie down instead of getting up to move around. Older adults and people on blood thinners should be watched more closely after a fall, because a head knock can cause bleeding that looks like ordinary sleepiness.
When to Call Poison Control or Go to the ER
Many gabapentin-only overdoses can be safely watched at home with guidance from a poison center.7PubMed. Characterization of gabapentin overdose using a poison center case series But across the US, about 1 in 6 people reported to poison centers after taking gabapentin alone needed care in a health facility.8PubMed. Trends in gabapentin and baclofen exposures reported to U.S. poison centers In the US, poison control is free and reachable at 1-800-222-1222 at any hour.
Call emergency services if the person is hard to wake, breathing slowly or shallowly, confused, or has lips turning blue. Get emergency help too if gabapentin was taken together with opioids, alcohol, benzodiazepines or sleep medicines. Treat any intentional overdose as an emergency, whatever the amount.
Have a few things ready when you call: the pill bottle, showing the strength in mg and how many pills are missing; the person’s weight and age, and whether they have kidney problems; every other medicine, drink or drug taken that day; and the time the pills were taken. Calling is worth it even when you feel fine. The staff are trained nurses and pharmacists, and a call doesn’t trigger an automatic ambulance, so there is no reason to wait and see first.
If you’re told to stay home, stay with the person and check that they wake when spoken to. Lay a very drowsy person on their side in case they vomit. Keep them from walking alone, using stairs, driving or bathing. If symptoms grow worse instead of easing, call back.
Why Gabapentin With Opioids or Other Sedatives Is Dangerous
Most deadly gabapentin poisonings involve other substances taken at the same time, especially opioids. Two effects stack. Gabapentin dulls the brain’s signal to breathe in response to rising carbon dioxide, on top of the same effect from opioids.9PubMed Central. Risk of major adverse events associated with gabapentinoid and opioid combination therapy: A systematic review and meta-analysis And opioids slow the gut, so gabapentin sits longer in the stretch of small intestine where it is absorbed, and more of it enters the blood.10PubMed Central. Gabapentin, opioids, and the risk of opioid-related death: A population-based nested case–control study A person on opioids therefore gets a stronger dose from the same pill and a bigger hit to breathing.11PubMed Central. Risk of major adverse events associated with gabapentinoid and opioid combination therapy: A systematic review and meta-analysis
Taking gabapentin alongside opioids is linked with a higher risk of dying from an opioid overdose.12PubMed Central. Gabapentin, opioids, and the risk of opioid-related death: A population-based nested case–control study Yet among hospital patients already on opioids, breathing problems happened about equally often (about 1 in 3) with or without gabapentin.13PubMed Central. Risk of respiratory depression with opioids and concomitant gabapentinoids One possible reason is that hospital monitoring catches problems early, so the danger may be greatest outside medical supervision.
Alcohol, benzodiazepines such as Xanax or Valium, and sleeping pills also slow breathing and alertness. Prescription combinations are common, so ask your prescriber or pharmacist if you take both.
Slowed breathing shows up as breaths that are slow, shallow or have long pauses. You may hear snoring or gurgling in someone who can’t be roused, and see bluish lips or fingertips and a limp body. Naloxone reverses opioid effects but not gabapentin; give it if opioids were involved, and still call 911.
Sleep is the riskiest time. Breathing naturally becomes shallower in sleep, so a drug that blunts the urge to breathe does its worst harm then. A person who has combined drugs and falls asleep may not wake to notice trouble, which is why someone else should check on them.
Kidney Problems and Older Age Raise the Risk
Gabapentin is not broken down by the liver; it leaves the body unchanged in urine.14PubMed Central. Rational dosing of gabapentin and pregabalin in chronic kidney disease How fast it is cleared therefore rises and falls directly with kidney function.15PubMed. Pharmacokinetics of gabapentin in subjects with various degrees of renal function Weaker kidneys mean higher blood levels and a much longer time for the drug to leave.16PubMed. Pharmacokinetics of gabapentin in subjects with various degrees of renal function With healthy kidneys toxicity is uncommon because the drug is cleared quickly.17PubMed Central. Myoclonus in renal failure: Two cases of gabapentin toxicity With no kidney function, it can take around 132 hours, about five and a half days, for blood levels to halve.18PubMed. Treatment of Gabapentin Toxicity With Peritoneal Dialysis: Assessment of Gabapentin Clearance
In one reported case, a woman on dialysis became severely dizzy and drowsy and slipped toward unconsciousness after a single normal dose.19PubMed Central. Gabapentin toxicity: an important cause of altered consciousness in patients with uraemia Build-up in people with kidney problems can cause sudden muscle jerks and confusion.20PubMed Central. Myoclonus in renal failure: Two cases of gabapentin toxicity An older man with kidney trouble developed nerve and brain symptoms as gabapentin accumulated.21PubMed. Gabapentin-induced neurologic toxicities
Signs that a normal dose is building up include new confusion, unusual sleepiness or slurred speech days after starting or raising the dose, twitching or jerking of the arms and legs, and worsening balance with new falls. These can be mistaken for a stroke or dementia, so mention gabapentin to any doctor.
A stable dose can also stop being safe. One that suited you for years can become too much if your kidneys decline, because the drug now stays in your blood longer and levels creep up. Dehydration, a serious infection or a new medicine that strains the kidneys can cause this change over days or weeks. The usual correction is a lower dose or a longer gap between doses, which only a prescriber can set after checking kidney tests.
Doctors adjust gabapentin by how well the kidneys filter, estimated from a blood test, not by age or weight alone. If you have kidney disease, an extra dose is more worrying than for someone with healthy kidneys, and you should call poison control right away.
In older adults gabapentin is linked with more falls and thinking problems, especially in the first year of use.22UPMC Palliative and Supportive Institute. Gabapentin: Updated Safety Concerns Ask whether your dose matches your current kidney test results, which change with age.
What Doctors Do in the Hospital
There is no antidote for gabapentin, so care focuses on watching breathing, heart rate and blood pressure until the drug clears. Most people with gabapentin-only overdoses are observed and sent home.23PubMed. Characterization of gabapentin overdose using a poison center case series Doctors may also give oxygen or fluids to keep a sleepy person comfortable and stable.
A visit typically starts with questions about the amount, timing and other drugs taken. You’ll be put on a heart monitor, with oxygen checked through a finger clip. Blood tests show kidney function, which shapes how long monitoring lasts. Once you are alert and walking steadily, often within the same day, you can go home.
Dialysis, a treatment that filters the blood when kidneys fail, is recommended when someone with kidney problems has symptoms of gabapentin build-up.24PubMed Central. Myoclonus in renal failure: Two cases of gabapentin toxicity In one patient, a single session brought a dramatic recovery.25PubMed Central. Gabapentin toxicity: an important cause of altered consciousness in patients with uraemia The gentler at-home form, peritoneal dialysis, cut the drug’s half-life from about 132 hours to about 41 and cleared symptoms in about 36 hours.26PubMed. Treatment of Gabapentin Toxicity With Peritoneal Dialysis: Assessment of Gabapentin Clearance Continuous blood filtering in intensive care has also been used for gabapentin toxicity.27PubMed Central. Treatment of gabapentin-induced myoclonus with continuous renal replacement therapy
When other drugs were involved, the approach widens. If opioids were taken, the team may give naloxone, which reverses the opioid but not the gabapentin, so the person still needs watching. Staff will usually look for other substances, such as acetaminophen, since some overdoses involve more than one drug and need specific treatment. Mixed overdoses usually mean longer observation, since breathing can slow again as medicines wear off.
Misuse and Taking More to Get High
Some people take large amounts for a high described as milder than opioids, or for calm and sedation.28PubMed Central. Gabapentin misuse, abuse, and diversion: A systematic review The sedation impairs judgment and coordination, which raises the chance of falls, car crashes and accidents. Most misuse happens alongside other drugs, especially opioids, to boost their effects or ease withdrawal, pain, anxiety or sleeplessness.29PubMed. Gabapentinoid Pharmacology in the Context of Emerging Misuse Liability Poison center reports of gabapentin misuse more than doubled in the US between 2013 and 2017.30PubMed. Trends in gabapentin and baclofen exposures reported to U.S. poison centers Several US states now treat gabapentin as a controlled drug or track its prescriptions.31LawAtlas. Legal Landscape of Gabapentin Drug Scheduling and Required Prescription Drug Monitoring
Very high doses can lead to true dependence, with craving and loss of control.32PubMed Central. Dependence on ultra-high doses of gabapentinoids: A case series With repeated high doses the brain adapts, so the same amount produces less effect and the person takes more to feel the same. Dependence differs from a simple need for a medicine, since it involves craving, using more than planned and continuing despite harm. People with a past history of substance use are more likely to develop problems and should tell their prescriber about it.
Signs that use is moving past the prescription include running out early, needing more for the same effect, taking it mainly to feel high or calm rather than for pain, and combining it with alcohol or opioids. A doctor can help taper safely; stopping abruptly carries its own risks.
Stopping Suddenly Can Also Cause Problems
Withdrawal has been reported in people taking 400 to 8,000 mg a day, after as little as 3 weeks of use.33PubMed. Akathisia induced by gabapentin withdrawal Symptoms resemble benzodiazepine withdrawal, including anxiety, restlessness, sweating and sleeplessness.34PubMed. Akathisia induced by gabapentin withdrawal In one case, symptoms began a day after stopping and grew over 10 days into severe confusion, chest pain and high blood pressure, easing within 1 to 2 days of restarting.35PubMed. Gabapentin withdrawal syndrome in the presence of a taper Reduce the dose gradually under medical guidance rather than quitting at once.
After weeks of regular use the nervous system adjusts to the drug, and removing it suddenly leaves the system overactive. Symptoms can start within a day or two of the last dose.
After a one-time extra dose, simply return to your normal schedule; withdrawal is a concern only after weeks of regular use. If you want to stop or cut back, tell your doctor so they can plan a taper.
A taper lowers the dose in small steps over days to weeks, and the pace is set by how long and how much you have been taking. If symptoms appear at a lower dose, the doctor can slow down or hold at that step before going further. Don’t make up your own schedule by splitting capsules or skipping days, since uneven doses can cause the same symptoms.
Children, Pets and Pregnancy
Any amount swallowed by a child warrants a call to poison control, because doses are sized for adults. Have the child’s age and weight, the strength of the capsules and how many may be missing ready, even if the child seems well. Don’t make the child vomit or wait for symptoms; poison control can say whether to watch at home or go in. Watch for unusual sleepiness, wobbliness or trouble waking, and call emergency services if the child cannot be roused or breathes oddly. Some children on gabapentin also develop hyperactivity and aggressive outbursts even at modest doses.36PubMed. Gabapentin toxicity in children manifesting as behavioral changes
Dogs and cats given high doses become sedated, wobbly and may vomit.37Merck Veterinary Manual. Toxicoses From Human Analgesics in Animals – Toxicology – Merck Veterinary Manual Call your vet or a pet poison line if a pet gets into the pills.
Gabapentin in pregnancy is linked with somewhat higher chances of preterm birth, a smaller baby and newborn intensive care.38PubMed Central. Gabapentin in pregnancy and the risk of adverse neonatal and maternal outcomes: A population-based cohort study nested in the US Medicaid Analytic eXtract dataset It was not linked with an overall rise in major birth defects.39PubMed Central. Gabapentin in pregnancy and the risk of adverse neonatal and maternal outcomes: A population-based cohort study nested in the US Medicaid Analytic eXtract dataset Don’t stop it in pregnancy without talking to your doctor.