MT17-002: Investigating appropriate dosing for gabapentin sedation in cats with and without chronic kidney disease. (An EveryCat-funded grant project, final published report)
Quimby, J. M., Lorbach, S. K., Saffire, A., Kennedy, A., Wittenburg, L. A., Aarnes, T. K., Creighton, K. J., Jones, S. E., Paschall, R. E., King, E. M., Bruner, C. E., Wallinger, J. N., & van Haaften, K. A. (2022). Journal of feline medicine and surgery
Stress associated with transportation, examination, and diagnostic procedures is a major barrier to providing quality feline health care. One popular therapeutic strategy to improve patient compliance and reduce stress has been the administration of the anticonvulsant drug gabapentin prior to vet visits. An early study concluded that a dose of 20mg/kg was effective for this purpose in healthy cats, but this dose may be inappropriate for elderly cats, specifically those with chronic kidney disease (CKD). Human studies have recommended Gabapentin doses be reduced in CKD patients, but no studies have been done in cats.
The purpose of this study was to characterize the pharmacokinetics of gabapentin administered at the accepted 20mg/kg stress-reduction dose in normal cats and compare this with the serum concentrations of gabapentin in cats with CKD at a reduced dose of 10mg/kg.
This was a clinical trial involving five client-owned healthy cats and 27 cats with stable IRIS stage 2 and 3 CKD. Initially, the five healthy control cats were administered 20mg/kg gabapentin orally, and then blood samples were obtained at 0, 0.25, 0.5, 1, 1.5, 2, 3, 4, 8, 12, 24, and 36h post-dosing. Later, all five control cats and the 27 CKD cats were dosed at 10mg/kg orally with blood samples obtained 3h and 8h post-dosing. Additionally, compliance scores were obtained on all CKD cats at 3h and 8h post-dosing, where three different clinical scenarios were staged, scored, and totaled. A higher score represented greater compliance.
Cats with CKD had significantly higher dose-normalized serum gabapentin concentrations than normal cats for both doses at both time points. Dose-normalized gabapentin serum concentrations at 3h and 8h were significantly correlated with serum Creatinine and SDMA, measures of kidney function used in IRIS staging. Compliance scores for cats with CKD were significantly increased at 3h versus 8h. Cats with higher serum gabapentin concentrations were more compliant at the 3h mark. No CKD cats were considered to be overly sedated at the 10mg/kg dose.
One limitation of this study was that all of the healthy cats were fairly young compared to the CKD cats so age may have played a factor, although this has not been demonstrated in human studies. Two CKD cats were excluded from data analysis because their serum gabapentin concentrations were higher at 8h than at 3h, and it was unclear whether this was a real phenomenon or an issue with capsule metabolism. Compliance scoring was not performed by the same individual each time, and no baseline compliance scores were performed prior to drug administration.
The authors conclude that dose reduction is likely needed when prescribing gabapentin to CKD patients as a pre-examination stress-reliever. This was demonstrated by the fact that dose-normalized serum gabapentin concentrations were significantly higher in the majority of cats with CKD compared to the healthy cats. Additionally, dose-normalized serum gabapentin concentrations were associated with serum Creatinine and SDMA, indicating that even greater caution is needed with advancing disease stages. -SdW
van Haaften, K. A., Forsythe, L., Stelow, E. A., & Bain, M. J. (2017). Effects of a single preappointment dose of gabapentin on signs of stress in cats during transportation and veterinary examination. Journal of the American Veterinary Medical Association, 251(10), 1175–1181. https://doi.org/10.2460/javma.251.10.1175
Anxiety; stress; renal failure; half-life; elimination rate