Last Updated: January 06, 2023

Understanding the Effects of Gabapentin Misuse

Gabapentin (brand name Neurontin) is a prescription medication that is FDA-approved to treat epilepsy and pain associated with nerve damage as a consequence of postherpetic neuralgia. However, up to 95% of gabapentin prescriptions are “off-label”, meaning that they are provided to treat something other than epilepsy or neuralgia. In 2016, over 64 million prescriptions were written for gabapentin; thus, up to 61 million prescriptions were written to treat conditions ranging from restless leg syndrome to drug and alcohol use disorders.

Gabapentin has long been considered to be a drug without the potential for abuse. However, mounting evidence suggests that gabapentin is being widely misused and, in conjunction with other drugs, abused. Gabapentin is frequently co-prescribed with opioids or benzodiazepines, and because it is not controlled or regulated in many states, there is a misperception that gabapentin lacks the potential for misuse or abuse. Many doctors are comfortable prescribing gabapentin to patients who have a history of opioid or other substance use disorders.

Before getting into a discussion about the risks of gabapentin misuse and abuse, it may be worth defining several common terms that can be confusing:

• Misuse refers to the use of a prescription drug in a way other than prescribed but without the intent to get high.
• Abuse is the use of a drug with the sole intent to get high. Drugs that are misused or abused are generally associated with the development of tolerance.
• Tolerance is when ever-increasing doses are required in order to achieve the same effect.
• Dependence indicates that physical withdrawal symptoms occur when drug use is reduced or stopped completely. Tolerance and dependence often go hand-in-hand.
• Addiction is an extension of dependence and is characterized by an inability to control drug-seeking behaviors, even in the face of negative consequences.

Short Term Side Effects of Gabapentin Misuse

Gabapentin use, both as prescribed and otherwise, is associated with common side effects:

• Physical side effects: Cold or flu-like symptoms, blurred vision, lack of coordination, tremors, nausea/vomiting, sleepiness, and dizziness. Further, unsteadiness or continuous back-and-forth/rolling eye movements are cause for alarm; if you see these symptoms, then contact your doctor immediately.
• Behavioral side effects: Depression, anxiety, hostility, confusion, mood swings, insomnia, and, rarely, aggression. Notably, children have higher rates of behavioral side effects than adults, including anxiety, depression, hyperactivity, mood swings, and an abnormal sense of distrust or a false sense of well-being. Changes in performance at school are also commonly reported.

One incredibly dangerous, albeit rare, side effect of gabapentin that occurs in a subset of people is a tendency towards suicidal ideation or attempt. People who experience suicidal behavior often have underlying mental health disorders. If you or someone you know is taking gabapentin and begins to display unusually depressive behavior, seek help immediately.

Long Term Side Effects of Gabapentin Misuse

There are no reliable reports of long-term side effects of gabapentin use. One uncited source indicates that long-term effects include memory loss, muscle weakness, and respiratory failure. However, people with chronic kidney disease are at risk for gabapentin toxicity that can have long-term consequences.

Gabapentin Overdose Risk & Symptoms

Gabapentin is generally well-tolerated over a wide range of doses, and reports of people taking astonishingly large amounts of gabapentin have been reported. For example, one report released by the Massachusetts/Rhode Island Poison Control System described the case of a 32-year-old man who ingested 91 grams of gabapentin along with the anticonvulsant valproic acid, beer, and whiskey. He displayed symptoms that were reminiscent of alcohol intoxication (dizziness, drowsiness, slurred speech) that fully resolved within 11 hours.

A 2014 study evaluated 116 reports of people who sought medical treatment for gabapentin overdoses, with doses ranging from 300 mg to 96 g. 97% of cases reported no effect or minor effect, with 3% requiring mechanical ventilation. All cases resolved fully and rapidly. Interestingly, the authors did not find a dose-response relationship, meaning that the person who took 96 grams was just as likely to have mild (or severe) symptoms as the person who took 300 milligrams.

The overwhelming majority of people who have dangerous or lethal gabapentin overdoses are also using other drugs, most often opioids. A large meta-analysis (1,256 cases) found that the combination of gabapentin and an opioid was associated with a significant increase in the risk of death. Importantly, while opioid overdoses can be treated, treatment of a gabapentin overdose is currently limited to supportive care. In instances of a combined opioid-gabapentin overdose, the presence of gabapentin proves to be lethal.

Gabapentin Abuse Statistics

Because it can substantially enhance the effects of opioids, gabapentin abuse is on the rise. Some studies estimate that up to half of the people who are prescribed opioids for pain management are also prescribed a “gabapentinoid” (gabapentin or its more dangerous relative, pregabalin). Interestingly, in a survey of people undergoing treatment for alcohol or opioid abuse, no one in the alcohol use disorder group reported having misused gabapentin, while 40% of people receiving treatment for opioid abuse had also abused gabapentin. Other studies, however, do report that alcohol and gabapentin are co-used.

In Ohio, gabapentin has become particularly prevalent. In 2017, Athens, Cincinnati, Cleveland, Columbus, Dayton, and Toledo all reported that gabapentin was moderately to highly available and that street availability and misuse/abuse were all increasing. In December 2016, gabapentin was the number one drug dispensed from Ohio pharmacies, with a 30% higher rate of dispensation than the second most frequent drug, which was the potent opioid oxycodone.

The trend seems to be continuing into 2019, with reports of increased availability of the brand name gabapentin, Neurontin, being reported in Cleveland and Athens despite Ohio having established a law that requires doctors and pharmacists to check a database to ensure that they are not supplying a prescription to someone who already has one.

How is Gabapentin Abused?

When taken as prescribed, gabapentin is ingested orally. However, snorting gabapentin is common among people who abuse it, and mixing gabapentin and opioids together before use is also common.

Recently, police reports have indicated that gabapentin has been identified as a common cutting agent in heroin.

Why Do People Abuse Gabapentin?

Understanding how gabapentin exerts its effects is helpful when discussing why it might be misused or abused. Gabapentin is a “GABA-mimetic”, meaning that it mimics the effects of a neurotransmitter, GABA, that is normally found in the brain. GABA has an inhibitory effect on brain activity, thereby preventing hyperexcitability that, left unchecked, would cause seizures or other negative outcomes. Many anti-anxiety drugs and pain medicines enhance GABA signaling, effectively limiting the ability of the brain to influence our behavior or experience physical sensations.

Drugs of abuse (notably opioids and benzodiazepines (Valium and Xanax are two popular benzodiazepines)) often enhance GABA neurotransmission. High doses of opioids or benzodiazepines lead to a sense of relaxed euphoria. Gabapentin is not normally considered to have a high risk for abuse because it affects GABA signaling in a different way than opioids and benzodiazepines and, when taken alone, is unable to provide the same sense of euphoria. However, when it is taken with opioids or benzodiazepines, the combination of drugs has a synergistic effect that results in a more intense high. This has resulted in people with opioid use disorders seeking out gabapentin as a supplemental drug in order to increase the psychotropic effects associated with the opioid high.

High doses of gabapentin are able to produce a euphoria that is “reminiscent of, but not as strong as, opioids”, especially when taken with other drugs or alcohol. Other commonly reported experiences associated with gabapentin misuse/abuse include sedation, calmness, and a “marijuana-like high”.