Gabapentin
Gabapentin. α2δ subunit of voltage-gated Ca²⁺ channels — reduces excitatory neurotransmitter release. Used for neuropathic pain + adjunctive… Oral half-life 6 h.
α2δ subunit of voltage-gated Ca²⁺ channels — reduces excitatory neurotransmitter release. Used for neuropathic pain + adjunctive seizure therapy + RLS. Renally cleared; no CYP. Dose-dependent absorption (saturable LAT1) — high-dose AUC plateaus.
PK: THE OLD CITATION WAS A RAT IN-SITU PERFUSION STUDY AND IT REFUTES THE VALUE IT WAS CITED FOR — its finding is that a saturable transport mechanism causes the lack of dose proportionality. Re-cited to human data (PMID:20818832), verbatim "elimination half-lives of approximately 6 hours". F 0.6 is retained but is valid ONLY AT 900 mg/day: the same source states bioavailability "drops from 60% to 33% as the dosage increases from 900 to 3600 mg/day", so a scalar overstates exposure at higher doses. ka 0.7 /h is dropped and must not be restored: gabapentin absorption is ZERO-ORDER through a saturable transporter, so a first-order rate constant is uncitable in principle rather than merely uncited. V 60 L has no source in any abstract.
Pharmacokinetics
- Oral — t½ 6 h · F 60%
Sources: PMID:8022536, PMID:20818832