Gabapentin has become the “go to” medication for companion cats to help reduce the anxiety associated with past and present veterinary visits. The protocol is fairly simple. Approximately 90 minutes prior to placing the cat in the carrier to visit the veterinarian, companion cat parents administer 100 mg of gabapentin (20 mg/kg) orally to their cats to help facilitate transfer, reduce stress, and increase examination compliance.
This gabapentin protocol was established with a randomized, blinded and crossover clinical trial in 20 healthy pet cats approximately five years ago.
In humans, gabapentin is cleared by the kidneys. People with chronic kidney disease (CKD) are often prescribed lower dosages of gabapentin because their kidneys are not clearing the medication. Signs of gabapentin toxicity in humans with CKD include reduced consciousness, unsteady gait or ataxia, dizziness or weakness, confusion, tremulousness and asterixis, which is more pronounced in patients with decreased renal function who have received higher doses.
Remember, cats are not humans, but many cats are diagnosed with CKD. By the way, cats with CKD may have an accumulation of waste products and other compounds in the bloodstream that are removed or regulated by the kidneys. The signs of CKD in cats are lethargy, urination, excessive water consumption, and weight loss.
Unfortunately, we do not know if gabapentin is cleared by the kidneys or not in cats. So, a group of researchers, led by Jessica Quimby of Ohio State University, investigated if the 100 mg/kg gabapentin dosage is adequate or excessive in cats with CKD or if cats with CKD should be given a smaller dose.
Indeed, anecdotal accounts demonstrated that the higher gabapentin doses (20 mg/kg or 100 mg/cat) can lead to excessive sedation and hypotension in cats with CKD, and a dose decrease of 50% is commonly practiced.
Before we get into the details, we must say that we are thoroughly impressed with the comprehensive work Jessica Quimby and Stacie Summers are completing and releasing regarding companion cats with CKD. They appear to frequently collaborate together along with others on significant research. From what we have seen thus far, Stacie Summers seems to be taking the lead from the inside out – studying the feline microbiome. Jessica Quimby works from the outside in from the perspective of frequently prescribed medications to cats with CKD. In fact, we would encourage veterinarians to read their work since CKD is so prevalent in companion cats.
Back to the study. Five healthy cats and 25 cats with CKD were enrolled in this study. The cats with CKD were of different breeds and either in stage 2 or stage 3 of kidney failure.
The research team measured gabapentin, symmetric dimethylarginine (SDMA), and creatinine concentration levels in the blood (serum) at three hours and eight hours after medication was given. Creatinine levels will indicate how well kidneys are performing at filtering waste from the body. SDMA is also a measurement of kidney function and is a sensitive circulating kidney biomarker.
Cats without CKD received a 20 mg/kg of gabapentin to establish a baseline. Then, cats in both groups were given a single 10 mg/kg dose of gabapentin.
The first question to be answered is patient compliance in cats with CKD. They found out that patient compliance was correlated to serum gabapentin concentrations at 3 hours post administration. None of the cats with CKD in this study were considered to be overly sedated at the 10 mg/kg dose. So, this means that the reduced dose was effective in being able to examine the companion cats.
You might be wondering about the reduced dose in healthy cats and the veterinarian’s ability to work with them. That was not within the scope of the study, and so was not addressed.
The health question needs to be answered.
The researchers discovered that at both 3 and 8 hours post-gabapentin administration that 92% of the cats with CKD that that received 10 mg/kg had a dose-normalized serum concentration higher than the upper range of healthy cats that received 20 mg/kg. Additionally, gabapentin was positively correlated with serum creatinine and SDMA in cats with CKD. Furthermore, cats with later stages of kidney disease may be more affected.
In conclusion, this study demonstrates that a dose reduction of gabapentin for cats with CKD would be wise.
References
Quimby JM, Lorbach SK, Saffire A, et al. Serum concentrations of gabapentin in cats with chronic kidney disease. Journal of Feline Medicine and Surgery. 2020;(0), doi:10.1177/1098612X221077017 https://journals.sagepub.com/doi/10.1177/1098612X221077017.
van Haaften, K. A., Forsythe, L. R. E., 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, doi:10.2460/javma.251.10.1175, https://avmajournals.avma.org/view/journals/javma/251/10/javma.251.10.1175.xml.