Gabapentin Overdose

Person laying on the ground next to a bottle of spilled gabpentin pills after overdosing

Gabapentin (brand name Neurontin) is an antiepileptic drug that is commonly prescribed to control seizures and manage neuropathic pain associated with diabetes. It is often prescribed off-label in the U.S. to treat other kinds of neuropathic pain as well as anxiety disorders, migraine headaches and insomnia. 

Gabapentin acts similarly to the neurotransmitter GABA, which reduces brain activity. This makes gabapentin efficient as an anti-seizure drug. However, its properties also give it a potential for misuse, especially when used with opioids or benzodiazepines. 

How Much Gabapentin is Too Much?

In general, gabapentin is well tolerated over a wide range of doses. However, a growing body of literature shows that gabapentin overdoses are possible and can cause potentially serious physical and psychological effects. Data suggests that the dosage amount may not be the biggest factor in an overdose. Factors such as polysubstance use and mental health play a significant role in overdose as well. 

For example, one study reported that a 32-year-old man tried to commit suicide by ingesting 91 g of gabapentin along with valproic acid and alcohol. His overdose symptoms included dizziness, drowsiness and slurred speech, but they were completely resolved after 11 hours. Another study identified 94 gabapentin users who sought medical help for gabapentin overdoses. Their doses ranged from 300 mg to 96,000 mg, and all cases were resolved with little or no toxic effects. Although some reports state that “gabapentin is fatal in overdose” without providing data or evidence, it is more likely that gabapentin overdose deaths are caused by polysubstance use (particularly opioids).

There is a growing concern among the medical community that gabapentin may be associated with adverse psychological effects in some people. A number of reports show that gabapentin can increase suicidal ideation and provoke suicide attempts in some people. However, it is unclear why this occurs, and data is confusing and often contradictory. What is clear is that some people respond poorly to gabapentin, and poor responses do not seem to depend on dosage amount.

Gabapentin Overdose Signs and Symptoms

The most common adverse physical reactions that are associated with gabapentin on its own include:

  • Dizziness
  • Swelling of hands and feet
  • Drowsiness
  • Clumsiness

Perhaps more concerning are psychological gabapentin overdose symptoms, which include:

Polysubstance use with gabapentin has been rapidly increasing, and the most commonly reported co-used substances are opioids, benzodiazepines and alcohol. Because gabapentin mimics GABA, using gabapentin with central nervous system depressants (benzodiazepines and opioids in particular) may increase addictive behaviors. Co-use of these drugs may result in unconsciousness and respiratory depression, which can be lethal.

Effects of Gabapentin Overdose

Gabapentin overdose side effects in the absence of other drugs are likely to be relatively harmless and short-term. The most common side effects include: 

  • Dizziness
  • Swelling of hands and feet
  • Somnolence

The psychological side effects are more concerning and include:

  • Depression
  • Anger
  • Wild mood swings
  • Violent behavior
  • Suicidal ideation or attempt

Many reports show that people who experience these psychological symptoms had previously diagnosed mood disorders, particularly bipolar disorder. However, it is clear that gabapentin may worsen both undiagnosed and diagnosed mental health disorders.

Opioids and benzodiazepines are commonly misused for the sense of euphoria that high doses can cause. The mechanism seems to be indirectly (opioids) or directly (benzodiazepines) related to GABA and activity reduction in dopamine-inhibiting cells. Combining drugs causes dopamine levels to rapidly increase in reward areas of the brain, leading to a perception of relaxed euphoria. 

So far, the evidence does not support that gabapentin alone is enough to create this effect. However, gabapentin may increase the effects of opioids or benzodiazepines by inhibiting the release of the excitatory neurotransmitter glutamate. This indirectly allows dopamine cells to become more active. Gabapentin used with opioids or benzodiazepines would increase the addictive nature of the pain relievers, creating health risks such as overdose. An overdose of gabapentin and opioids or benzodiazepines can cause side effects of lethargy, respiratory depression and loss of consciousness.

Gabapentin Overdose Statistics

Currently, it is difficult to say how dangerous it is to use gabapentin on its own. However, gabapentin does have the potential to worsen the current opioid crisis. In 2016, there were 64 million Americans with gabapentin prescriptions. Around 56% of those people also had a prescription for an opioid, and 27% had a prescription for gabapentin, opioids, muscle relaxants or anti-anxiety medication. 

A 2017 study estimated that 15–22% of people who misused gabapentin also misused opioids. Another 2017 study found that the odds of an opioid-related death increased by 60% when gabapentin was used at the same time. In 2018, gabapentin became the 13th most prescribed medication in the U.S., and the opioid hydrocodone was the 9th most prescribed. Taken together, these studies suggest that using gabapentin and opioids together can have lethal consequences.

Gabapentin Overdose Treatment

In the absence of another drug, gabapentin overdose treatment is limited to supportive care. When combined with a central nervous system depressant, an overdose may cause respiratory depression and coma, potentially requiring artificial ventilation to ensure airflow. If you suspect a gabapentin overdose, call 911. 

Gabapentin Overdose Prevention

The best way to avoid an overdose is to not take gabapentin. If you have a prescription, take it as prescribed. A growing body of literature suggests that gabapentin itself is not associated with a substantial risk of overdose. When gabapentin is used with opioids or benzodiazepines, however, the risk increases significantly. If you have prescriptions for both drugs, talk to your doctor to make sure you are not at risk for dangerous drug interactions. 

If you or a loved one is struggling with gabapentin addiction, The Recovery Village Ridgefield is here to help. Contact us today to speak with an addiction expert and learn about our comprehensive rehabilitation programs.

Smith, Rachel V.; Havens, Jennifer R.; Walsh, Sharon L. “Gabapentin misuse, abuse, and diversion: A systematic review.” Addiction, March 2016. Accessed August 10, 2019.

Solla, Bridget, “GABAPENTIN (Neurontin).” Clinical Toxicology Review, December 2001. Accessed August 22, 2019.

Wills, Brandon; Reynolds, Penny; Chu, Eileen; Murphy, Christine; Cumpston, Kirk; Stromberg, Paul; Rose, Rutherfoord. “Clinical Outcomes in Newer Anticonvulsant Overdose: A Poison Center Observational Study.” Journal of Medical Toxicology, February 2014. Accessed August 10, 2019.

Smith, Blair H. “Substance misuse of gabapentin.” British Journal of General Practice, August 2012. Accessed August 10, 2019.

Gomes, Tara; Juurlink, David N.; Antoniou, Tony; Mamdani, Muhammad M.; Paterson, J. Michael; van den Brink, Wim. “Gabapentin, opioids, and the risk of opioid-related death: A population-based nested case–control study.” PLoS One, October 2017. Accessed August 10, 2019.

Patorno, Elisabetta; Bohn, Rhonda L.; Wahl, Peter M. “Anticonvulsant Medications and the Risk of Suicide, Attempted Suicide, or Violent Death.” The Journal of the American Medical Association, April 2010. Accessed August 10, 2019.

Ghaly, Ramsis F.; Plesca, Ana; Rana, Shalini; Candido, Kenneth D.; Knezevic, Nebojsa Nick. “Gabapentin-related suicide: Myth or fact?” Surgical Neurology International, October 2018. Accessed August 10, 2019.

Guiffre, Kyle; Wegrzyn, Erica L. “Gabapentin and Suicidal Ideation: Is There a Link?” Practical Pain Management, July 2019. Accessed August 10, 2019.

Pinnintim, Narsimha R.; Mahajan, Deepak S. “Gabapentin-Associated Aggression.” The Journal of Neuropsychiatry, August 2001. Accessed August 10, 2019.

Leith, Wendy; Lambert, William; Boehnlein, James; Freeman, Michael. “The association between gabapentin and suicidality in bipolar patients.” International Clinical Psychopharmacology,  January 2019. Accessed August 10, 2019.

Keskinbora, Kader; Pekel, Ali Ferit; Aydinli, Isik. “Gabapentin and an Opioid Combination Versus Opioid Alone for the Management of Neuropathic Cancer Pain: A Randomized Open Trial.” Journal of Pain and Symptom Management, August 2007. Accessed August 10, 2019.

Utah.gov. “The greatest threat of gabapentin occurs when used with a prescription opioid.” 2018. Accessed August 10, 2019.

Fuentes, Andrea V.; Pineda, Moises D.; Nagulapalli Venkata, Kalyan C. “Comprehension of Top 200 Prescribed Drugs in the US as a Resource for Pharmacy Teaching, Training and Practice.” Pharmacy, May 2018. Accessed August 10, 2019.

Toxicology Data Network. “Gabapentin.” February 2017. Accessed August 10, 2019.

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