What are the contraindications (CI) for gabapentin?

Contraindications for Gabapentin

Gabapentin has only one absolute contraindication: hypersensitivity to the drug or its ingredients. 1

Primary Contraindications and Precautions

Gabapentin is generally well-tolerated with a favorable safety profile compared to many other medications. However, several important precautions should be considered:

Absolute Contraindication

• Hypersensitivity: Patients with known hypersensitivity to gabapentin or any components of the formulation 1

Major Precautions (Relative Contraindications)

1. Renal Impairment:

   • Gabapentin is exclusively eliminated by the kidneys
   • Significant dose adjustment required in chronic kidney disease
   • Risk of toxicity increases linearly with decreasing renal function 2
   • In dialysis patients, elimination half-life increases from 5-9 hours to 132 hours 3

2. Pregnancy and Breastfeeding:

   • Should be used with caution during pregnancy
   • Women of reproductive potential should receive counseling regarding contraception 4

3. Central Nervous System Depression:

   • Caution with concurrent use of other CNS depressants
   • Combined use with alcohol or depressant drugs can worsen cognitive impairment 4

Monitoring and Dose Considerations

Renal Function Monitoring

• Monitor electrolytes and creatinine before and during treatment 4
• Dose adjustment required for patients with renal impairment:
  • Inappropriate dosing in renal impairment is a common cause of toxicity 2
  • Elderly patients with multiple comorbidities are at higher risk 2

Side Effects to Monitor

Common side effects include:

• Dizziness (19%)
• Somnolence/drowsiness (14%)
• Peripheral edema (7%)
• Gait disturbance (14%)
• Unsteadiness 4, 5

Special Populations

Dialysis Patients

• Extreme caution required
• 77.8% of dialysis patients may experience toxicity with standard dosing 2
• Symptoms of toxicity are more severe in dialysis patients compared to those with less severe renal impairment 2

Elderly Patients

• Higher risk of adverse effects
• More susceptible to CNS effects (dizziness, somnolence)
• Often have reduced renal function requiring dose adjustment 2

Clinical Pearls

1. Gabapentin toxicity is often underrecognized:

   • Initial suspicion of gabapentin toxicity occurs in only 41.5% of symptomatic cases 2
   • Symptoms may be mistakenly attributed to other conditions

2. Symptoms of toxicity:

   • Altered mental status
   • Dizziness
   • Somnolence
   • Ataxia
   • Increased risk of falls and fractures 3

3. Risk-benefit assessment:

   • For chronic neuropathic pain, benefits may outweigh risks in appropriate patients 4
   • Regular reassessment of risk-benefit profile recommended (at least every 6 months) 4

4. Discontinuation:

   • Unlike some other medications (e.g., SSRIs/SNRIs), gabapentin does not have a significant withdrawal syndrome 4
   • However, abrupt discontinuation should be avoided with higher doses

Gabapentin remains a valuable medication for neuropathic pain, epilepsy, and other conditions when used appropriately with attention to these contraindications and precautions.