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Pregabalin vs Gabapentin

Both pregabalin and gabapentin are GABA analogues that bind to presynaptic neuron’s voltage-gated calcium channels (VGCC), specifically to the alpha-2-delta protein leading to reduced calcium influx at the nerve terminals. This leads to reduced release of excitatory neurotransmitters. Though the compounds are similar they have few important differences that must be considered.

PregabalinGabapentin
FDA approved indicationsDiabetic peripheral neuropathy (DPN), Fibromyalgia, Postherpetic neuralgia (PHN), Partial seizuresPHN, Epilepsy
Time to maximal absorption0.8-1.4 hours2-3 hours
Oral bioavailability>90% all doses 35%-57% dose dependent
Elimination half life4-7 hours5-9 hours
Drug interactionsNo significant drug interactionsOral antacids reduce bioavailability by 20-30%
Starting dose2 times a day : 75-150 mg/day (dose reduction required with renal insufficiency)3 times a day :100-900 mg/day (dose reduction required with renal insufficiency)
TitrationIncrease weekly by 50-150 mg/day towards maximal tolerated doseIncrease weekly by 300-900 mg/day towards maximal tolerated dose
Usual effective dose150-600 mg/day1200-2400 mg/day
Maximum dose600 mg/day3600 mg/day
Pharmacokinetic profileLinear (plasma concentration is dose proportionate)Non-linear (plasma concentration increases disproportionately to dose)
Onset of action1-2 days9 or more days
Therapeutic indexGreater (less adverse effects)Lesser (more adverse effects)

References and further reading:

  1. Gilron I, Flatters SJ. Gabapentin and pregabalin for the treatment of neuropathic pain: A review of laboratory and clinical evidence. Pain Research and Management. 2006;11(Suppl A):16A-29A.
  2. How Gabapentin Differs From Pregabalin (pharmacytimes.com)
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