In an elderly patient scheduled for total knee arthroplasty with less than 48 hours before surgery, is reducing the gabapentin dose from 600 mg twice daily beneficial instead of attempting a full taper?

Perioperative Gabapentin Management in Geriatric Total Knee Arthroplasty

In a geriatric patient on gabapentin 600 mg BID with less than 48 hours before total knee arthroplasty, continue the current dose rather than attempting dose reduction, as gabapentin provides beneficial opioid-sparing analgesia and abrupt discontinuation poses seizure risk.

Rationale for Continuing Current Dose

Opioid-Sparing Benefits Outweigh Risks

• Gabapentin should be continued perioperatively as part of multimodal analgesia to reduce postoperative opioid consumption and improve pain control. 1

• Enhanced Recovery After Surgery (ERAS) guidelines specifically recommend gabapentinoids as preoperative medication for their opioid-sparing effects, though they emphasize using the "single lowest preoperative dose" to minimize sedation, dizziness, and visual disturbances. 1

• In elderly patients undergoing non-cardiac surgery (mean age 72 years), gabapentin 900 mg preoperatively and for three postoperative days resulted in significant opioid reduction, though it did not reduce delirium rates. 1

Withdrawal Seizure Risk

• Abrupt gabapentin discontinuation carries serious risk of withdrawal seizures, including status epilepticus, even in patients without prior seizure history. 2

• The FDA label explicitly states: "If the gabapentin dose is reduced, discontinued, or substituted with an alternative medication, this should be done gradually over a minimum of 1 week (a longer period may be needed at the discretion of the prescriber)." 3

• A case report documented status epilepticus in a patient who discontinued gabapentin after only 2 days without medication, demonstrating the rapid onset of withdrawal complications. 2

Why Dose Reduction is Not Helpful in <48 Hours

Insufficient Time for Safe Taper

• The minimum safe taper period is one week per FDA guidance, making any meaningful dose reduction impossible within 48 hours. 3

• Attempting partial dose reduction in this timeframe provides no protection against withdrawal complications while potentially destabilizing the patient's current pain control. 3

Elderly-Specific Considerations

• In geriatric patients, gabapentin dosing should be adjusted based on renal function (creatinine clearance), not arbitrarily reduced for surgery timing. 1

• The ERAS guidelines emphasize that in elderly patients and those with renal dysfunction, gabapentinoid doses should be "adjusted accordingly and used with further caution," but this refers to appropriate dosing based on pharmacokinetics, not preoperative tapering. 1

• Starting doses for elderly patients should be low (gabapentin 100-200 mg/day), but this patient is already on chronic therapy at 1200 mg/day total, which falls within the therapeutic range of 900-3600 mg/day. 1, 3

Practical Management Strategy

Preoperative Approach

• Continue gabapentin 600 mg BID through the morning of surgery. 1

• Verify renal function and adjust dose only if creatinine clearance is significantly impaired (see FDA dosing table for renal adjustment). 3

• Alert the anesthesia team to the patient's gabapentin use to anticipate potential additive sedative effects with anesthetic agents. 1

Postoperative Continuation

• Resume gabapentin at the preoperative dose once oral intake is tolerated, typically within 24 hours after total knee arthroplasty. 1

• Monitor closely for excessive sedation, dizziness, and peripheral edema, which are common gabapentinoid adverse effects that may be amplified by postoperative opioids. 1

• Consider that gabapentin's opioid-sparing effect may allow for reduced postoperative opioid dosing, potentially offsetting some sedation concerns. 1

Critical Caveats

Sedation and Delirium Risk

• While gabapentin reduces opioid consumption, it increases postoperative sedation, dizziness, and visual disturbances—effects particularly problematic in elderly patients. 1

• A large trial in elderly surgical patients (mean age 72) found no reduction in postoperative delirium with gabapentin despite opioid-sparing effects. 1

• The sedative effects are dose-dependent, reinforcing that the current dose should be maintained rather than increased, but not reduced acutely. 1

Renal Function Monitoring

• Gabapentin is renally cleared and not metabolized, making dose adjustment essential in renal impairment. 3, 4

• For creatinine clearance 30-59 mL/min, the FDA recommends 400-1400 mg/day in divided doses; for 15-29 mL/min, 200-700 mg/day as a single daily dose. 3

• Elderly patients are more likely to have decreased renal function, necessitating creatinine clearance calculation using the Cockcroft-Gault equation. 3