Contraindications for Gabapentin
The only absolute contraindication for gabapentin is hypersensitivity to the drug or its ingredients. 1
Primary Contraindications and Precautions
Gabapentin has a remarkably favorable safety profile with minimal absolute contraindications compared to many other medications. However, several important precautions should be considered:
Renal Impairment
- Gabapentin requires dose adjustment based on creatinine clearance:
- CrCl ≥60 mL/min: 900-3600 mg/day (300-1200 mg TID)
- CrCl 30-59 mL/min: 400-1400 mg/day (200-700 mg BID)
- CrCl 15-29 mL/min: 200-700 mg/day (once daily)
- CrCl ≤15 mL/min: 100-300 mg/day (once daily) 2
Risk of Falls and Altered Mental Status
- Increased risk of falls or fractures (RR 1.35) and altered mental status (RR 1.12) compared to non-users
- Clear dose-response relationship with highest risk at doses ≥2,400 mg/day (RR 1.90 for falls/fractures) 3
- Particular caution needed in elderly patients who should be started on lower doses and titrated more slowly 2
Pregnancy and Breastfeeding
- Not recommended for women who are pregnant, actively trying to conceive, or nursing
- Women of reproductive potential should receive counseling regarding reliable contraception methods 4
Special Population Considerations
Elderly Patients
- Start with lower doses and titrate more slowly
- Monitor closely for side effects, particularly dizziness, somnolence, and gait disturbance 2
Patients with History of Substance Abuse
- Potential for abuse, particularly in patients with:
- History of opioid abuse
- Mental illness
- Previous prescription drug abuse history 5
- Some states have reclassified gabapentin as a Schedule V controlled substance due to abuse potential 5
Patients on Monoamine Oxidase Inhibitors
- Unlike some other medications used for neuropathic pain (e.g., phentermine), gabapentin has no known contraindications with MAOIs 4
Common Side Effects to Monitor
- Dizziness (19% of patients)
- Somnolence (14%)
- Peripheral edema (7%)
- Gait disturbance (14%) 6
- Side effects typically mild to moderate and usually subside within approximately 10 days from treatment initiation 7
Dosing Considerations
When using gabapentin for unexplained chronic cough or neuropathic pain, start with 300 mg once daily and gradually increase:
- Day 1: 300 mg once daily
- Day 2: 600 mg daily (divided)
- Day 3 onward: 900 mg daily (divided)
- Additional titration to 1800 mg/day recommended for greater efficacy
- Some patients may require up to 3600 mg/day 4, 7
Monitoring Recommendations
- Evaluate response every 2-4 weeks during dose titration
- Assess improvement in symptoms and monitor for adverse effects
- Consider discontinuation if inadequate response after 4-8 weeks at maximum tolerated dose 2
Gabapentin's favorable safety profile with minimal drug interactions makes it a versatile option for various conditions, but careful consideration of patient-specific factors and appropriate dose adjustments are essential for safe and effective use.