Rabbits/Anaphylactic Shock in Rabbits
Can rabbits develop anaphylactic shock from injectable penicillins, and if so, is it treatable? We had a going-on-11yrs.- old, yet very active and playful rabbit that developed a tooth root abscess. It was successfully treated with injectable penicillin, but returned a few months later. Back on the "pen-benz", the abscess appeared to be responding once again. Due for his next dose, I gave him the injection as usual, but within 30 seconds he appeared to lose control of his limbs. He tried to lunge away, but after that could not move again. Our regular rabbit savvy vet kept denying on phone that anaphylactic shock was possible, and given what seemed an extremely urgent scenario to us, we rushed him to another rabbit savvy vet, closer. They too, refused to believe it could be a reaction to the penicillin and started some diagnostics but would not "treat" him with anything. Of course, he did not make it. In hindsight, we can't believe we did not have a necropsy done, but that's beside the point now. We just would like to know about anaphylactic shock in rabbits and whether it is treatable. We've had rabbits for 20 years and have experienced some tragic losses, but this was a new one for us. Thank you in advance for your time.
I am so very sorry for the tragic loss of your friend.
As for the anaphylaxis...I am truly stunned that the veterinarians did not believe that this was the problem. OF COURSE rabbits--like any mammal--can develop sensitivity to penicillin, which is a powerful sensitizing agent. What you describe is exactly what we have seen in several of our rabbits and hares who developed an allergy to penicillin.
Sometimes they survive, but sometimes they succumb, and that usually happens within a few hours. But swift treatment with ephinephrine is a must, and supportive care (fluids, keeping the patient warm, etc.) will also help. Allergic reaction to penicillin should be treated the way any anaphylactic reaction should be treated, no matter what the species. (The only exception is that it's best to avoid corticosteroids in rabbits. But if it's life or death, then you have to do what you have to do.)
Another possibility is a vascular embolism caused by the penicillin. If you were using the veterinary formulation of dual-acting Pen G/Benzathine, it is very thick and viscous. If you accidentally hit a blood vessel and the suspension enters the bloodstream, a quick and fatal obstruction can result. This is why you must never inject the veterinary formulation intramuscularly, and should always draw back on the plunger when adminitering it subQ, to be sure you haven't hit a blood vessel. Your bunny's ataxia could also signal that he had suffered a penicillin embolism.
It would be very difficult to detect either anaphylaxis or embolism via gross necropsy. Histopathology on major organ tissues might show clues. But possibly nothing certain could be determined, even if you had had a necropsy done.
I hope this can help give you some closure. I am so very sorry.