Both medications are often used to treat neuropathic pain and epilepsy
Mechanism: Both work via inhibition of Ca+ influx and block release of excitatory neurotransmitters. However, exact mechanism not known!
Both drugs can be taken without food
Neither drug binds to plasma proteins
Both drugs are renally excreted and not metabolized by the liver (CYP Enzymes)
Half-life of both is ~6 hours
DIFFERENCES
Pregablin (Lyrica)
Gabapentin (Neurontin)
Also indicated for fibromyalgia, and generalized anxiety disorder.(Better for seizure reduction),
rapid absorption (peak concentration in 1-2hrs)
Absorption is linear (first order), therefore Pregablin plasma concentration increases proportionately with increasing dose.
slower absorption (peak concentration in 3-4hrs)
Oral gabapentin exhibits saturable absorption; pharmacokinetics less predictable (zero-order)
Gabapentin plasma concentration does not increase proportionally with increasing dose
**pregabalin may have some pharmacokinetic advantages over gabapentin; This may be the reason for improved pharmacodynamic effect.
REFERENCES
Bockbrader HN, Wesche D, Miller R, Chapel S, Janiczek N, Burger P. A comparison of the pharmacokinetics and pharmacodynamics of pregabalin and gabapentin. Clin Pharmacokinet. 2010 Oct;49(10):661-9. doi: 10.2165/11536200-000000000-00000.