Adverse reaction to appetite stimulant or something else?

Our 16 year old male, Marble, has had a decreased appetite for the past few months. Some days he'll barely eat 1/4 can of food on his own so we've had to syringe feed him to make up for it. He was just diagnosed with pancreatitis. Our vet gave us buprenorphine, cerenia and mirtazapine. The mirtazapine kicked in within a few hours but would only last for about 36 hours. After his 3rd dose (day 9) he started frantically meowing and started biting my arm which he's never done. It happened the next day as well, this time when I was in bed and he tried to bite my face. Upon speaking to our vet, we decided to try cyproheptadine, starting with 2mg/day. He had his second dose this morning and same thing - came into the bedroom and was biting my hair and frantically pawing at my head (I was sleeping on my stomach with the blankets pulled up so he could only get my hair thankfully).

Has anyone heard of such an aggressive reaction to mirtazapine and/or cyproheptadine.  I just noticed that the vet hadn't quartered the mirtazapine so we'd been giving 7.5mg every 3 days which is super high. The cypro hasn't kicked in as an appetite stimulant yet so I don't know how well it will work. Could it be the drugs causing this reaction or something like dementia or a tumor or something?

I originally jumped to blaming the drugs as it happened within hours of the third dose of mirtazapine. But then with it happening again on the cypro I'm not sure. I know they both affect the brain, but I can't find anything online about reactions like this...

Hi catsandcritters and welcome to the forum !

I have very little time, so I'll just drop off a couple of references for you.

On what may have happened/is happening, have a read of this (from a well-respected website): http://www.felinecrf.org/persuading_cat_to_eat.htm#serotonin_syndrome

Note that, if this is the problem, the cyproheptadine may be the 'fix'.......share the links with your Vet and decide on a course of action.

Here's a short and comprehensive '101' of pancreatitis: http://www.felinecrf.org/pancreatitis.htm

Because pancreatitis can be a complicated and frustrating condition to manage, there has been a specialized online community that focuses on it....they are here: https://beta.groups.yahoo.com/neo/groups/Feline_Pancreatitis_Support/info     I'd really recommend you join up.....these group members are often more knowledgeable on a practical level (and, beyond that as well) than many Vets.

Hope some of that will help !

Hi White Shadow! Thanks for the reply!

I'm pretty familiar with Tanya's site, as Marble's brother Rye was diagnosed with Stage 4 kidney failure 5 years ago. Her site was our Bible as we fought the disease for 6 months before losing him. I've tried all the tricks on the Persuading Your Cat to Eat page with Marble, with no luck so that's why we opted for appetite stimulants.

My concern was serotonin syndrome with the mirtazapine, but his last dose (again, apparently 7.5mg) was on Friday night and it's now Wednesday night, so I would assume it would all be out of his system? Especially with us starting the cypro yesterday afternoon. But then he was biting at me again this morning. So now we're wondering if the cypro is affecting him as well, or if something else is going on.

We've had another cat with chronic pancreatitis that had flareups every 2-3 months requiring hospitalization, so we're familiar with all the links you posted, but thanks! Never hurts to refresh the brain. Our other cat Winky hasn't had a flareup for over 2 years now! Yay! Hopefully we can get Marble on the right track.

I think we're just going to stop ALL meds for a few days and get everything out of his system and see if he's still biting/being frantic. I know all these drugs, mirt, cypro, cerenia, work on the brain and it would seem like a BIG coincidence that something else is going on but just happened to start showing signs when we started the drugs.  But then we're back to square one with him not eating well.

Yes, these drugs 'work on the brain'.........

That was an enormous dosage - overdose - for starts, and, I have no idea as to how long it takes to clear the drug.

Did you read the 'recommended' dose for the Cypro:

Cyproheptadine (Periactin)  

Cyproheptadine comes in 4mg tablets. Whilst Plumb's Veterinary Drug Handbook mentions a dose of 1 - 4mg once or twice a day for a cat, many people on Tanya's CKD Support Group have found a dose of 0.5mg once per day works well and also seems to reduce the risk of the side effects mentioned above. Therefore you may wish to ask your vet if you can start at this level, increasing it only if necessary.

http://www.felinecrf.org/persuading_cat_to_eat.htm#cyproheptadine

[blue = my emphasis]

Click to expand...

I can't discuss a dosage with you....but...there is a huge range of strengths coming out of that particular drug handbook. She (Helen) writes that 1/2mg works well for many people in her group. I think you should consider this, discuss w the Vet and decide on dosage based on that info. I certainly would.

Ok, so I was wrong about him getting 7.5mg....the bottle I was looking at was when he was prescribed it last fall and we ended up not needed it, so he HAS been getting 3.75mg. Still high according to some sites, but not nearly as bad.

I was going to start at the 0.5mg dose of cypro but went with the higher to counteract the mirtazapine. In any event, he hasn't had mirt for 7 days, no cerenia for 3 days and no cypro for 2 days, and he's still attacking me. It happened again this morning while I was in bed.

All the drugs *should* be out of his system by now, so I think something else must be going on. The last few times has been while I've been in bed in the morning and I've been lucky enough to be able to pull the duvet over myself to protect my face so he's still only getting my hair/ponytail, but it's scary as it's just so unlike him