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:
- Swelling of hands and feet
Perhaps more concerning are psychological gabapentin overdose symptoms, which include:
- Suicidal ideation
- Erratic or violent behavior
- Extreme mood swings.
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:
- Swelling of hands and feet
The psychological side effects are more concerning and include:
- 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.
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