Pregabalin is a neuroactive drug used to treat partial-onset (focal) seizure disorders, neuropathic pain, and anxiety in humans. Like gabapentin, a drug more commonly used in veterinary medicine for the control of seizures due to epilepsy and for neuropathic pain control, pregabalin seems to work as a close structural relative to gamma-aminobutyric acid. It binds to calcium channels, thereby decreasing calcium influx, and results in a reduced release of glutamate and substance P at the synapse. The authors studied 6 adult dogs weighing an average of 33 kg. Each dog was administered 1 oral dose of pregabalin at 4 mg/kg, a dose extrapolated from human doses used to control seizures. Blood samples drawn at regular intervals revealed that the drug has an average elimination half-life of 7 hours. This is consistent with existing data from studies performed in humans. Anecdotally, the authors report that side effects in dogs treated with 4 mg/kg
pregabalin Q 8 H for 8 to 12 weeks included somnolence and lethargy. In humans receiving pregabalin, 50 to 600 mg/kg Q 12 H for 12 weeks, side effects included somnolence, dizziness, and headaches. Although further studies are needed to confirm therapeutic efficacy and safety of pregabalin for epilepsy and neuropathic pain management, the administration of a single oral dose did not produce obvious adverse effects in the study animals; plasma drug concentrations may be achieved with twice-daily dosing.
Commentary: Although practitioners debate the dosing of gabapentin in treating neuropathic pain in dogs, it is thought that adequate pain control might be achieved with a lower dose than that needed for antiseizure activity. Anecdotally, pregabalin is also used to treat neuropathic pain in dogs and has exciting potential as a once- or twice-daily drug with minimal side effects, at doses much lower than that tested in this study. It will be very interesting to see how pregabalin functions in the standard regimen for dogs with chronic pain.
Pharmacokinetics of single-dose oral pregabalin administration in normal dogs. Salazar V, Dewey CW, Schwark W, et al. VET ANAESTH ANALG 36:574-580, 2009.