Comparative Pharmacology
Head-to-head clinical analysis: GABAPENTIN versus TEGRETOL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: GABAPENTIN versus TEGRETOL.
GABAPENTIN vs TEGRETOL
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.
Voltage-gated sodium channel blocker; stabilizes neuronal membranes and inhibits repetitive firing. Also inhibits glutamate release and enhances GABA activity.
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.
Initial: 200 mg orally twice daily; increase by 200 mg/day at weekly intervals. Maintenance: 800-1200 mg/day in 2-4 divided doses. Maximum dose: 1600 mg/day. Extended-release: 200-400 mg twice daily.
None Documented
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
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.
Single dose: 25–65 hours (mean ~35 h); chronic therapy: 12–17 hours due to autoinduction; clinical context: requires 3–4 weeks to reach steady-state after dose adjustment.
Renal: 76-81% unchanged in urine; biliary/fecal: <5% as metabolites; remainder (10-20%) as minor metabolites via urine.
Primarily hepatic metabolism; ~72% excreted in urine (as metabolites, <2% unchanged), ~28% excreted in feces via bile.
Category A/B
Category C
Anticonvulsant
Anticonvulsant
"The risk or severity of adverse effects can be increased when Gabapentin is combined with Clemastine."