Clinical signs of cats with chronic kidney disease (CKD) commonly include drinking and urinating excessively, lethargy, decreased appetite, weight loss and vomiting. Poor body condition has been found to correlate with decreased survival in CKD cats; therefore, nutrition is important for improving long-term prognosis, and treatments that directly alleviate nausea and improve appetite are desired.
Interestingly, the exact mechanism of why CKD cats suffer from decreased appetite and vomiting is not currently known. Gastrin hormone that is responsible for stomach acid production is elevated in CKD cats; however, increased stomach acidity and stomach ulceration have not been document in humans or cats with CKD. It is suspected that CKD cats have an increase in toxins referred to as uremic toxins that trigger the vomiting center (chemoreceptor trigger zone of the area postrema) in their brains.
Dr. Jessica Quimby at Colorado State University Department of Clinical Sciences and co-workers investigated the uses of maropitant, a selective neurokinin-1 (NK-1) receptor inhibitor that directly blocks the binding of substance P to the NK-1 receptor thus shutting down the vomiting center. The researchers showed in a double-blind, placebo-controlled, multi-institute prospective study involving 33 cats (i.e., 21 cats receiving maropitant, and 12 cats receiving placebo) with Stage II or III CKD that orally administered maropitant significantly decreased vomiting over a 2-week trial period. However, within the 2-week trial period it did not appear to significantly improve appetite or result in weight gain in cats with Stage II and III CKD. Longer clinical trials and studies in late-stage CKD disease are needed to better assess the effect of maropitant on weight gain and nutrition in CKD cats.
