Gabapentin and Pregabalin: Different Medications in the Same Class
No, gabapentin and pregabalin are not the same medication - they are distinct but related drugs in the same medication class (calcium channel α2-δ ligands). 1
Similarities Between Gabapentin and Pregabalin
- Both are calcium channel α2-δ ligands that are structurally related to GABA (gamma-aminobutyric acid) 1, 2
- Both are primarily used for treatment of neuropathic pain conditions and as adjunctive therapy for seizures 1, 2
- Both medications have similar side effect profiles, with dizziness and somnolence being the most common adverse effects 3, 2
- Both drugs are eliminated primarily unchanged through the kidneys, requiring dose adjustments in renal impairment 3, 2
Key Differences Between Gabapentin and Pregabalin
- Pregabalin (brand name Lyrica) has linear pharmacokinetics, while gabapentin has nonlinear absorption 2, 4
- Pregabalin has higher bioavailability (approximately 90%) compared to gabapentin 4
- Pregabalin reaches therapeutic doses more quickly and at lower doses than gabapentin 5
- Pregabalin is FDA-approved for diabetic neuropathy, postherpetic neuralgia, fibromyalgia, and neuropathic pain associated with spinal cord injury, while gabapentin is only FDA-approved for postherpetic neuralgia (for pain indications) 6
- Pregabalin is classified as a Schedule V controlled substance due to potential for abuse and dependence, while gabapentin is not federally scheduled (though some states regulate it) 2
Clinical Effectiveness Comparison
- In studies of patients with postherpetic neuralgia, patients prescribed pregabalin were more likely to reach therapeutic doses with their first prescription (69.0%) compared to those prescribed gabapentin (3.5%) 5
- A higher proportion of patients reached therapeutic doses by their third consecutive prescription with pregabalin (89.3%) compared to gabapentin (46.2%) 5
- Some evidence suggests that opioid use decreased after initiation of pregabalin but increased after initiation of gabapentin in patients with postherpetic neuralgia 5
Dosing Considerations
- Gabapentin starting dose: 100-300 mg at bedtime or 100-300 mg three times daily, with titration by 100-300 mg every 1-7 days as tolerated 1, 7
- Pregabalin starting dose: 50 mg three times daily or 75 mg twice daily, with increases to 300 mg/day after 3-7 days 1
- Maximum doses: Gabapentin up to 3600 mg/day; Pregabalin up to 600 mg/day 1, 7
- Both medications require lower starting doses and slower titration in elderly patients 3, 7
Common Precautions for Both Medications
- Both are contraindicated in pregnancy or when actively trying to conceive 3
- Both require dose adjustments in renal impairment 3, 2
- Both can cause dizziness and somnolence (23-46% and 15-25% of patients respectively) 3
- Both can cause peripheral edema (approximately 10% of patients) 3
- Both should be tapered gradually rather than discontinued abruptly 7
While these medications are often used interchangeably in clinical practice for similar indications, they are distinct pharmaceutical agents with important differences in pharmacokinetics, dosing, and regulatory status.