What is the management of Gabapentin (Neurontin) overdose?

From the Guidelines

Gabapentin overdose management should focus on supportive care, prioritizing airway protection, respiratory support, and hemodynamic stabilization, as there is no specific antidote. The initial steps in management include maintaining the patient's airway and breathing, which can be achieved through rescue breaths and bag-mask ventilation, as recommended by the American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1.

Key Considerations in Management

• Activated charcoal may be administered if the patient presents within 1-2 hours of ingestion and is alert with a protected airway.
• Intravenous fluids should be given to maintain hydration and support blood pressure.
• Hemodialysis can be considered in severe cases with significantly elevated gabapentin levels (>100 mg/L) or in patients with renal impairment, as gabapentin is primarily eliminated through the kidneys 1.
• Monitoring for and treating symptoms including CNS depression, ataxia, nystagmus, dizziness, and respiratory depression is crucial.
• Seizures, though uncommon, may occur and should be treated with benzodiazepines such as lorazepam 2-4 mg IV or diazepam 5-10 mg IV.
• Continuous cardiac monitoring is recommended as gabapentin overdose can cause cardiac conduction abnormalities.

Outcome and Prognosis

Most patients recover fully with supportive care within 24-48 hours due to gabapentin's relatively short half-life of 5-7 hours in patients with normal renal function. The severity of overdose correlates with the amount ingested, timing of medical intervention, and the patient's underlying health status, particularly renal function. It is essential to prioritize high-quality CPR and standard resuscitative measures over naloxone administration in cases of suspected opioid overdose, as naloxone is ineffective in non-opioid overdoses and cardiac arrest from any cause 1.

From the FDA Drug Label

Overdosage A lethal dose of gabapentin was not identified in mice and rats receiving single oral doses as high as 8000 mg/kg. Signs of acute toxicity in animals included ataxia, labored breathing, ptosis, sedation, hypoactivity, or excitation. Acute oral overdoses of gabapentin up to 49 grams have been reported In these cases, double vision, slurred speech, drowsiness, lethargy, and diarrhea were observed. All patients recovered with supportive care. Coma, resolving with dialysis, has been reported in patients with chronic renal failure who were treated with gabapentin. Gabapentin can be removed by hemodialysis Although hemodialysis has not been performed in the few overdose cases reported, it may be indicated by the patient’s clinical state or in patients with significant renal impairment. If overexposure occurs, call your poison control center at 1-800-222-1222

Gabapentin overdose management involves:

• Supportive care for patients with symptoms such as double vision, slurred speech, drowsiness, lethargy, and diarrhea
• Consideration of hemodialysis in patients with significant renal impairment or those who are in a coma
• Contacting the poison control center at 1-800-222-1222 in case of overexposure 2

From the Research

Gabapentin Overdose Management

• Gabapentin overdose can lead to respiratory depression, especially when combined with opioids 3, 4, 5.
• The risk of respiratory depression and opioid-related death is increased when gabapentin is co-prescribed with opioids 3, 4, 5.
• A study found that concomitant gabapentin use was associated with a significantly increased odds of opioid-related death (odds ratio 1.99,95% CI 1.61 to 2.47, p < 0.001) compared to opioid prescription alone 5.
• Management of gabapentin overdose includes supportive care and monitoring, as most patients experience minimal toxicity 6.
• In cases of gabapentin overdose, clinical effects typically develop early and resolve within 10 hours, with symptoms such as drowsiness, dizziness, nausea/vomiting, tachycardia, and hypotension 6.

Treatment Approaches

• There is limited research on the specific treatment of gabapentin overdose, but a literature review suggests that recognizing the unique toxicity profiles of gabapentin and other substances is imperative in providing optimal resuscitative care 7.
• Healthcare providers should be aware of the potential for gabapentin overdose and take steps to prevent it, such as closely monitoring patients who are prescribed gabapentin and opioids concurrently 3, 4, 5.
• In cases of overdose, patients should be managed in a healthcare facility with supportive care and monitoring, as needed 6.

Key Considerations

• Gabapentin and opioids should be prescribed concurrently with caution, as the combination can increase the risk of respiratory depression and opioid-related death 3, 4, 5.
• Healthcare providers should be aware of the potential for gabapentin overdose and take steps to prevent it, such as educating patients about the risks and monitoring them closely 3, 4, 5.
• Further research is needed to fully understand the risks and management of gabapentin overdose, particularly in combination with other substances 7.