Mirtazapine, a tricyclic depressant for humans, has been shown to have appetite stimulant benefits for cats. Since cats who have a decreased appetite can develop life-threatening conditions such as hepatic lipidosis, this medication can have important uses in cats.
A recent study at Colorado State University looked at the use of mirtazapine in cats with liver disease. It has already been established that cats with kidney disease are slower to clear this drug from their systems, but it was not known if this would be true for cats with liver disease as well. Eleven cats with liver disease and 11 control cats were in the study. In addition, liver cells from seven cats who had to be euthanized but were not in the study (three with liver disease and four with other illnesses) were studied to investigate drug metabolism in an in vitro (laboratory) situation.
The primary concern was to determine if current dosing protocols were appropriate for cats with liver disease, as such cats comprise a large segment of the cats who might be prescribed this drug. The dosing schedule for cats with kidney failure has been suggested as once every two days instead of once daily. The study suggests a similar change in dosing would be better in cats with liver disease.
This was a limited study in that the numbers of cats involved are not great and there may be differences in drug metabolism depending on the exact type of liver disease a cat was suffering from. Still, it is a step in the right direction and suggests changes in dosing protocols would be ideal for cats with liver disease. n