Famciclovir and Vomiting

hopscotch

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Hi, I have a cat, Oreo, who is recovering from a flare-up of feline herpes that caused some eyes issues that are being treated.  She is seeing a vet opthamologist and is close to the end of 2 weeks of oral Famciclovir (anti-viral) medication.  The dosage is a 1/4 of a 250mg tablet twice a day for a 15.5 lb cat.

Yesterday I forgot that Famciclovir should be given after a meal and gave her the morning dose in a pill pocket before her breakfast.  She ate breakfast right after eating the pill pocket and then threw up breakfast and the partially digested pill shortly thereafter.  I brushed it off as my mistake since I had heard that Famciclovir can cause vomiting on an empty stomach.

Oreo had no problem with her evening meal and dose last night, or with the one this morning.  However, tonight I gave her the Famiciclovir about 10 minutes after eating and within 10-15 minutes again she threw up dinner and the dose.  I am wondering if recently I'm giving the dose too soon after she eats.

I already spoke to her regular vet about this just a little while ago today, since I want to make sure this isn't pancreatitis re-emerging, which I thought we just treated and were just over.  I'll also call the vet opthamologist tomorrow to get her opinion on this and what to do.  But I'd really like to hear from anyone who has given a round of Famciclovir treatment for a herpes flare-up.  Did you have any issues with kitty feeling nauseous and does what I described sound familiar?  I hope the vomiting does not continue when we stop the medication in about two days.
 

stephanietx

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According to this http://www.vetspecialtytucson.com/LibraryForms/FamciclovirUseFelineHerpes.pdf, approx 40mg -90mg per kg of weight per day is the dose.  If you're giving 1/4 of a 250 mg tablet, that's 62.5 mg twice a day or 125mg daily.  That amount may be too strong for your kitty and as it's built up in his system, his body is now unable to handle it.  I would call the prescribing vet and stop giving it to him. 

What else are you doing to control/manage his herpes?  Does he eat grain free food and are you giving Lysine twice daily?  What type of symptoms does he have when he has a flare up?

Here's another TCS thread about herpes in the eye and treatment.  http://www.thecatsite.com/t/183179/feline-herpes-virus-and-famciclovir
 

simka

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Bee has been on several rounds of Famciclovir and has never become nauseated.
 
 
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hopscotch

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Oreo's doing fine today.  I gave her morning dose at least a half hour after she ate and all is well.  Her vet said that it could have been the timing of the dose with the food.  I'm not getting an indication that the dosage is more than she can handle since she's not vomiting all the time and I don't want to second guess the vet on implications of stopping treatment early because we need to make sure the herpes is back under control.  I've already checked with another vet and they said the dosage for her situation is right.  I tend to be on the careful side from the start.

There's a bit of a story behind the herpes that started in late June.  I noticed a tear by her eyes that was still there 3-4 days later.  Normally, it would have cleared up on its own by this time so I was thinking of getting it looked at.  It just so happened that same afternoon she suddenly developed slight aniscoria.  Both pupils were light responsive, but one was more dilated.  I took Oreo to the vet the next day for a check-up and blood work but they didn't find anything wrong.  I suspected this was related to feline herpes because of the tear, but there was no test of or diagnosis of herpes at this time.  The vet said that 45% of the time they find no reason for aniscoria like this and that it might go away on its own.  All other behaviour, eating and the litter box was normal.

Three weeks later I noticed that there was a very light brown/tea coloured staining developing around the outside edges of her corneas (the clear parts).  When we did a dye test, we found that the pigmentation was inside the cornea rather than on the surface.  She was referred to a vet eye specialist.  The vet opthamologist said Oreo's eye pressures were normal and the pigmentation wasn't the normal manifestation for anterior uveitis, but there was clear indications that she did have anterior uveitis, though by this time it was inactive.  The opthamologist prescribed prednisolone acetate drops for a month, which started as 4 times a day for the first week and then tapered off.  This treatment was prescribed to slow down or halt tea staining of the cornea.  The long term treatment was to be a daily non-steroidal drop.  The pigmentation has now stopped, but the amount that's there will always remain.

Three weeks into the treatment I noticed what looked like melting ice on the surface of one eye with a small spot of cloudiness and so I immediately took her back to the eye specialist.  We did another dye test and found it was a large superficial eye ulcer that had formed in about one day.  The cloudiness was from inflammation.  Because of the history I mentioned and the ulcer breaking out after steroidal drops, we are pretty confident that she did have feline herpes. Steroidal drops are known to risk bringing out eye ulcers if the cat carries herpes.

The doctor stopped the prednisolone drops and we started 2 weeks of oral Famciclovir, low dosage oral buprenorphine (painkiller), anti-biotic drops (preventative since the ulcer was not infected), non-steroidal anti-inflammatory drops, and serum drops (also for faster healing).  Unfortunately, I had to go away for 3 days after that (timing was really bad!) so I got her medical boarding with a local 24 hour emergency clinic.  Though she was good at the beginning toward the end she had a stress meltdown (they had a trauma come in and I think she must have heard it) and I had to arrange for an early pick-up.

Due to the stress meltdown, the herpes flared-up up again for 2 days and her eyes looked awful (lots of pink conjunctivitis, squinting, tearing and cloudiness).  It looked to me that she had an ulcer on her other eye and so I took her back to the eye specialist the next day, and the eye doctor confirmed that the stress and herpes would have likely done this again even though we were getting treatment.  The dye test found a large superficial ulcer in the other eye and so I started the same treatment on that.  We stopped the anti-inflammatory drops because even though they are non-steroidal they can slow healing and added sodium chloride drops to dry out the cornea and help it heal faster.

The good news is that all of this worked!  Within 3-4 days she was rechecked by the eye specialist and the second large ulcer was completely healed and the first eye was about 99% healed.  A week after stopping the anti-inflammatory drops, we re-started the non-steroidal anti-inflammatory drops now, and are continuing preventative antibiotic treatment in both eyes and the sodium chloride in the 99% healed eye until another recheck after Labour Day.  Oreo's healing quickly an it's expected that she'll be totally fine by then.  I can't see the tiny amount of ulcer in the one eye anymore, so I would not be surprised if it's already gone.

I am also giving Oreo L-Lysine gel long term in her food twice daily now as a preventative measure against a future outbreak.  Her food is Medical Weight Management, which was recommended by the vet because she needs to lose some wait and to minimize risk of a pancreatitis flare-up.
 
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