Gabapentin and pregabalin:
- Are both structural analogues of GABA
- Have no direct action on the GABAA receptor
- Act on the α2δ subunit of voltage gated Ca2+ channels in the CNS, inhibiting neurotransmitter release
- May have some NMDA receptor activity
Comparison of GABA Analogues
|Uses||Focal seizures, neuropathic pain||Focal seizures, neuropathic pain, anxiety|
|Route of Administration||PO|
|Dosing||100mg TDS, increasing up to 1200mg TDS||50mg BD/TDS, up to 600mg in divided doses (BD or TDS)|
|Absorption||PO bioavailability of 60%, decreases with increasing dose due to saturation of transporter||90% PO bioavailability, delayed by food but unaffected by dose|
|Distribution||Minimally protein bound||Minimally protein bound|
|Metabolism||Not metabolised||Not metabolised|
|Elimination||Renal elimination of active drug, t1/2β 6 hours||Renal elimination of active drug, t1/2β 6 hours|
|CNS||Drowsiness, ataxia, psychiatric symptoms||Confusion, psychiatric symptoms, drowsiness|
- Taylor CP, Angelotti T, Fauman E. Pharmacology and mechanism of action of pregabalin: the calcium channel alpha2-delta (alpha2-delta) subunit as a target for antiepileptic drug discovery. Epilepsy Res. 2007 Feb;73(2):137-50. Epub 2006 Nov 28.
- Peck TE, Hill SA. Pharmacology for Anaesthesia and Intensive Care. 4th Ed. Cambridge University Press. 2014.