Gabapentin typically starts working in cats within 1 to 2 hours after administration. Its peak effectiveness is usually about 2 to 3 hours after giving the medication. The effects can last between 8 to 12 hours, and the medication is generally cleared from the cat’s system within about 24 hours if given as a single dose. The exact timing can vary based on factors like the cat’s age, weight, metabolism, and kidney function. For anxiety or stressful situations, giving gabapentin 2 to 3 hours before the event is recommended to maximize its calming effects. Long-term use may require dose adjustments due to tolerance.