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Antibiotics & rabbits?

22 10:38:43

Question
Can rabbits have an allergic reaction to antibiotics? My 4 yr old house bunny Oscar, a mini lop, started peeing outside the litter tray, he appeared to be healthy & was eating ok & running round with my other rabbits. A urine strip test revealed nitrates & a trace of leukocytes. The vet gave him injectable trimethoprim for 5 days. He had never had antibiotics before & seemed a bit off colour the next day & later on began passing motions which contained mucous. After 3 doses his gut stopped working & he had to be given metoclopramide to restart his gut, which worked & he was eating, cleaning & looking much better. However despite my concerns the antibiotics had caused the gut stasis the vet advised for the course of antibiotics to be finished although Oscars urine was now free of nitrates & he was back peeing in his litter tray. His urine did however now contain a small amount of protein which the vet said was probably down to the infection the antibiotics were treating. I gave him the 2 further doses of antibiotic as advised & little Oscar did not like it. He seemed off colour again & was eating less after the 4th dose & after the 5th stopped eating & was grinding his teeth in pain. His ears were also very cold. I took him back to the vet who checked his teeth & said his tongue appeared to be ulcerated & something was going on with his back molars. He was admitted immediately for dental surgery the same day. The surgery went well & he came round from the anaestetic the vet took bloods as it was felt there might be an underlying disorder as the vet had seen rabbits with far worse teeth who were still eating. Unfortunately Oscar passed away sometime in the night & was found by the vet nurse in the morning. The bloods that were taken came back from the lab showing inreased neutrophils, platelets, and mild anaemia. Biochemistry showed massive levels of creatine & urea in his blood & also suggested he was metabolising his own muscles. He had lost 6oz of weight in 5 days. Would the fact that he had had an anaestetic have an bearing on the blood results? I know anaestesia is risky in any rabbit but the vet said Oscar appeared to be making good progress. Apart from peeing on the carpet Oscar appeared to be for all intents & purposes a healthy bunn & only went downhill following adminestration of antibiotics. Could he have suffered an allergic reaction to the antibiotics? I know humans can have this, with catastrophic results in extreme cases. Is it possible for this to have happened & if so would it have brought about renal failure or kidney damage? Can antibiotics cause ulceration in the gastro tract? Why did my bunny die? I know nothing's going to bring him back but I can't believe he had severe kidney disease when he seemed so fit & healthy a week before dying. Sorry I've gone on a bit but any knowledge you can share would not only help me understand why Oscar might have died but might help someone else as well. thankyou

Answer
Dear Tracey,

I am very sorry about the very sad loss of your Oscar.  From what you've told me, he passed away from renal failure.  The high BUN, creatinine and wasting are clear evidence of that.

So much seems to have been going on with him that it might be hard to pinpoint exactly what was going on.

You don't say whether the vet took a sample of urine for culture and sensitivity testing, but this would have been a good way to start, to be sure the most effective antibiotics were being employed:

www.bio.miami.edu/hare/culture.html

Loss of litterbox habits can, indeed, signify a urinary tract problem, but it can be many different things, from a urolith (bladder stone) to bladder sludge to an infection anywhere along the tract, from bladder to kidneys.

A kidney infection can cause renal failure, and it's more likely that bacteria--not antibiotics--were at the root of this.  Trimethoprim sulfa is metabolized via the kidneys, which is why many vets will use this first for a urinary tract infection.  But unfortunately, we are finding that more and more strains of bacteria are entirely resistant to the sulfas (which have been around a LOOOOONG time).  In the slim chance that Oscar was being treated with an antibiotic that wasn't killing the bacteria, then the infection might simply have been progressing without obvious signs, and caused his kidneys to fail.

Animals in renal failure will often get mouth ulcers, so it might have been the kidney problems, and not the teeth, that caused this.  Stress and inappetence can cause GI tract ulcers, as can certain types of analgesics (NSAIDs and corticosteroids), but I've not heard of trimethoprim sulfa causing them.

I'm sorry that it may not be possible to know exactly why Oscar's kidneys failed.  There could be many possibilities.  

I hope it's some small comfort to know that he had you loving him for his whole life, even if his life was too short.  He will always live in your heart.

Take care,

Dana