Dear Greyce, I just read your blog entry (15 Things to Aks About Medication) and now I have a question. I'm a sprayer (I admit this doesn't make me the most popular guy in the household) and the vet gave me a medication to take. A month later, the vet decided to switch medications. Why? Silvester the Sprayer
Dear Silvester, Before I take a stab at the possible reasons for switching your medication, let me stand on my cat tree and pontificate. First, I hope you also had a behavioural program in place while you were taking it. Because without such a program the chance for success is not high. Second, did you train your purrsons to keep a record of your behaviour with the medication? Hopefully they had some idea of what was going on before you starting taking it (after all that was probably the reason they took you to the vet); this is called 'baseline' - your behaviour before the medication - and is used as the basis by which to judge success. In order to figure out if there is improvement when you are using the medication, your folks need to keep careful records. Otherwise everyone is just relying on memory.
For example, I often get letters from cats who say their folks complain that they are spraying around the house or that they spray all the time. But when I ask them to keep records, the story changes. "Around the house" might mean "four different locations" (in may cases, always the same ones). And "all the time" might mean "twice a week" in the first location, "once" in the second location, and "less than that" in the rest. And the frequency and use of locations might actually be changing with time (or other events) but no one quite remembers. Do you see what I'm getting at?
If you return to the vet with only recall and the vet ask your folks, "So how has Silvester been doing with this medication" and they say, "Well he still sprays everywhere all the time," what do you think the vet will conclude? That the medication is NOT working! Or that there is something else which your folks haven't mentioned that is preventing progress from being made.
So now that I've made a case for good record-keeping, let me answer your question.
There are several possible reasons.
First reason: The medication is not working for you. I am going to paraphrase the words of Dr. Karen Overall (in her book Clinical Behavioral Medicine for Small Animals): There is no single medication that is useful for urine spraying. There is no single medication that is useful for aggression. The reason: Either or both behaviours can be triggered by many different circumstances and as such, affect different parts of the brain. Bottom line: There are several different medications that could be used and your vet will choose the one thought to be the most appropriate. But nonetheless that medication may not work for you. If that medication wasn't helping you stop spraying -- and that would be apparent by your spray history, purrhaps your vet believed that you needed to try something else.
Second reason: Undesirable side-effects. While all medications can be associated with side-effects, some are more tolerable than others. And some might endanger other aspects of your health. If such a side-effect happens to you, the vet will switch medication to something you are likely to be better able to tolerate.
Third reason: New information. Again to paraphrase Dr. Karen: A medication has specific properties. In order to know if it is working (i.e., the right medication), the vet must also know what behavioural changes have/have not happened on the medication, and lots of details about the social and physical environment in which you live (including any changes while you are on the medication). Sometimes your vet might ask a question or your folks might mention something in passing that suggests another medication might be more effective. For example some medications for spraying have the added effect of increasing confidence. If you are in a household where you are being bossed around by another cat (and that may be contributing to your need to spray), then such a medication could help you stand up to that other cat and thus alleviate your need to express yourself through urine marking. However many humans don't recognize the signs of 'bossing' unless it really gets out of hand - like out-and-out fights with blood and tufts of fur on the floor; and so they might not mention it to the vet because they don't know that it is important.
If the vet understands cat behaviour problems AND is skilled at questioning, that vet will pursue the topic from a number of ways. Starting with: How DO Sylvester and Twister get along? And then: Do they sleep together? Play together? Have either of them yowled or yelped when they play? etc. In fact, some vets may require your folks to fill out detailed forms on your history before medication is prescribed; and then, follow up forms, before every follow up consultation. But there are vets who either don't have such skill, or don't have or take the time to do this. There are also folks who are unwilling to pay for the time. Enough said.
Bottom line: Why not ask your vet?