Gabapentin exhibits an unusual pharmacokinetic property: doubling the oral dose does not double plasma concentrations, and bioavailability actually falls from about 60 percent at low doses toward 35 percent or less at high doses. This occurs because:

• A Intestinal uptake via the neutral amino acid transporter LAT1 is saturable ✓
• B Gabapentin undergoes extensive first-pass glucuronidation
• C Gabapentin strongly induces P-glycoprotein in enterocytes
• D Gabapentin forms insoluble complexes with dietary fat

Explanation

Gabapentin crosses the gut wall exclusively through a saturable L-type neutral amino acid transporter, so transporter capacity limits absorption at higher doses and bioavailability declines as dose increases. It is not metabolized at all and is excreted unchanged renally, which eliminates options B and C, and pregabalin was developed partly because its linear, dose-proportional absorption avoids this ceiling.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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