Comparative Pharmacology
Head-to-head clinical analysis: GABAPENTIN versus LAMICTAL CD.
Peer-Reviewed Evidence
Head-to-head clinical analysis: GABAPENTIN versus LAMICTAL CD.
GABAPENTIN vs LAMICTAL CD
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Gabapentin is a structural analog of GABA but does not bind to GABA receptors. It binds to the α2δ subunit of voltage-gated calcium channels, reducing calcium influx and decreasing the release of excitatory neurotransmitters.
Lamotrigine is a phenyltriazine anticonvulsant that stabilizes neuronal membranes by blocking voltage-sensitive sodium channels and inhibiting the presynaptic release of excitatory neurotransmitters such as glutamate and aspartate.
Initial dose: 300 mg orally once daily on day 1, 300 mg twice daily on day 2, then 300 mg three times daily on day 3; titrate as needed up to 1800-3600 mg/day in three divided doses. Maximum single dose: 1200 mg. Dose adjustments for renal impairment should be made based on creatinine clearance.
Lamotrigine extended-release (LAMICTAL CD) for epilepsy: initial 50 mg orally once daily for 2 weeks, then 100 mg once daily for 2 weeks, then 200 mg once daily for 2 weeks, then 300 mg once daily for 2 weeks, then 400 mg once daily thereafter. For bipolar disorder: initial 25 mg once daily for 2 weeks, then 50 mg once daily for 2 weeks, then 100 mg once daily for 2 weeks, then 200 mg once daily thereafter.
None Documented
Clinical Note
moderateGabapentin + Fluticasone propionate
"The risk or severity of adverse effects can be increased when Gabapentin is combined with Fluticasone propionate."
Clinical Note
moderateGabapentin + Erythromycin
"The metabolism of Erythromycin can be decreased when combined with Gabapentin."
Clinical Note
moderateGabapentin + Fluconazole
"The serum concentration of Fluconazole can be increased when it is combined with Gabapentin."
Clinical Note
moderateGabapentin + Clemastine
None Documented
5-7 hours (normal renal function); prolonged to 50-140 hours in end-stage renal disease; half-life independent of dose due to linear kinetics.
Terminal elimination half-life in adults is approximately 25.4 hours (range 14-50 hours) in healthy volunteers; reduced to 14.5 hours (range 12-20) with enzyme-inducing antiepileptics (e.g., carbamazepine, phenytoin), increased to 59 hours (range 30-90) with valproate, and prolonged in renal impairment.
Renal: 76-81% unchanged in urine; biliary/fecal: <5% as metabolites; remainder (10-20%) as minor metabolites via urine.
Lamotrigine is primarily eliminated by hepatic metabolism, with approximately 94% of the dose excreted in urine as glucuronide conjugates (10% as unchanged drug) and 2% in feces.
Category A/B
Category C
Anticonvulsant
Anticonvulsant
"The risk or severity of adverse effects can be increased when Gabapentin is combined with Clemastine."