What is the treatment for gabapentin (Neurontin) overdose?

Treatment of Gabapentin Overdose

Supportive care is the mainstay of treatment for gabapentin overdose, with hemodialysis recommended for patients with severe toxicity, particularly those with renal impairment or requiring mechanical ventilation. 1, 2

Clinical Presentation

Gabapentin overdose typically presents with:

• CNS depression: drowsiness, lethargy, slurred speech
• Double vision
• Ataxia (loss of coordination)
• Diarrhea
• Respiratory depression (in severe cases)
• Coma (in severe cases)

Acute oral overdoses of up to 49 grams have been reported with patients recovering with supportive care 1.

Treatment Algorithm

First-Line Management:

1. Airway, Breathing, Circulation (ABC) Management

   • Secure airway if patient has decreased consciousness
   • Provide supplemental oxygen if needed
   • Support blood pressure with IV fluids if hypotension present

2. Contact Poison Control Center (1-800-222-1222) for case-specific guidance 1

3. Supportive Care

   • IV fluid administration
   • Cardiac monitoring
   • Frequent neurological assessments
   • Management of symptoms as they arise

Specific Interventions:

For Mild to Moderate Toxicity:

• Observation and supportive care only
• Monitor for progression of symptoms
• No specific antidote exists for gabapentin

For Severe Toxicity:

• Indications for Hemodialysis:
  • Patients with decreased kidney function AND coma requiring mechanical ventilation 2
  • Patients with chronic renal failure who develop coma 1
  • Consider for patients with normal renal function but severe, life-threatening symptoms

Evidence Quality and Considerations

The FDA drug label clearly states that gabapentin can be removed by hemodialysis, and that hemodialysis may be indicated based on the patient's clinical state or in patients with significant renal impairment 1. This is supported by the EXTRIP Workgroup's systematic review which found that gabapentin is highly dialyzable with clearance >150 mL/min and a shortened elimination half-life <5 hours during hemodialysis 2.

However, the EXTRIP Workgroup suggests against performing extracorporeal treatment for gabapentinoid poisoning in patients with normal kidney function (weak recommendation, very low quality of evidence) 2. This is because severe toxicity, mortality, and sequelae are rare in cases receiving standard care alone.

Special Considerations

• Renal Impairment: Patients with renal impairment are at higher risk for toxicity as gabapentin is primarily excreted unchanged in urine. The elimination half-life increases from 5-9 hours in normal renal function to 132 hours in patients on dialysis 3.

• Rhabdomyolysis: Rare cases of gabapentin overdose-induced rhabdomyolysis requiring renal replacement therapy have been reported 4. Monitor creatine kinase levels in severe overdoses.

• Mortality Risk: While most patients recover with supportive care, fatal cases due solely to gabapentin toxicity have been reported 5. This underscores the importance of appropriate monitoring and intervention.

Monitoring Parameters

• Level of consciousness
• Respiratory rate and effort
• Blood pressure and heart rate
• Renal function (BUN, creatinine)
• Creatine kinase (to detect rhabdomyolysis)
• Serum gabapentin levels (if available)

By following this approach to gabapentin overdose management, focusing on supportive care and utilizing hemodialysis in appropriate cases, clinicians can optimize outcomes for these patients.