Gabapentin to pregabalin therapy transition: a pharmacokinetic simulation

Area of Science:

• Pharmacokinetics
• Pharmacology
• Clinical Pharmacy

Background:

• Gabapentin and pregabalin are commonly prescribed anticonvulsants and analgesics.
• Clinicians may need to transition patients between these medications due to efficacy or tolerability.
• Optimal transition strategies require understanding drug pharmacokinetics.

Purpose of the Study:

• To evaluate and compare two distinct dosage regimens for transitioning patients from gabapentin to pregabalin.
• To guide clinical practice by assessing the pharmacokinetic profiles of different transition designs.

Main Methods:

• Population pharmacokinetic modeling was used to simulate two transition designs: immediate discontinuation and gradual coadministration.
• Simulations were performed across three dosage levels (e.g., gabapentin 900 mg/d to pregabalin 150 mg/d).
• Drug exposure was assessed as pregabalin-equivalent concentrations.

Main Results:

• Both immediate and gradual transition designs resulted in predicted pregabalin-equivalent concentrations comparable to steady-state monotherapy.
• A rapid and seamless transition was observed, with concentrations stabilizing within one day of initiating pregabalin or discontinuing gabapentin.
• The simulated transition regimens did not lead to significant deviations in drug exposure.

Conclusions:

• Transitioning from gabapentin to pregabalin can be effectively managed using either an immediate or a gradual approach.
• Pharmacokinetic modeling supports the theoretical feasibility of both assessed transition strategies.
• These findings provide valuable insights for clinicians managing medication switches between gabapentin and pregabalin.