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Senior dog has watery diarrhea on meds. Should I be worried?

Updated On September 23rd, 2025

Pet's info: Dog | Labrador Retriever | Female | spayed | 11 years and 6 months old | 90 lbs

Summe my senior 11 yr old lab has been coughing and now watery diarrhea since last night. She is on antibiotics for bacteria and steroids to make her lumps smaller and on lasix to take out fluids in her lungs. Now vet said to give her probiotics and metrodinazole. For her diarrhea which is urgently alarming me. What do I do?

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1 Answer

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Answered By Lauren Kennedy, DVM

Veterinarian

Published on October 15th, 2017

It is hard to say if the diarrhea is related to Summer’s respiratory issues or not. If it was parasites causing the problem, they certainly could be related. Also, sometimes certain antibiotics can upset the gut flora (the normal bacteria in the gut) and can cause diarrhea. Regardless of the cause of the diarrhea, starting Summer on metronidazole and a probiotic is a good idea. This is the typical treatment for diarrhea. I can understand that having your dog on two different antibiotics can be concerning but sometimes it is necessary. Metronidazole is great for diarrhea because it specifically targets the type of bacteria that overgrows causing the diarrhea. At this point I would recommend continuing the current therapy your vet prescribed. The diarrhea should start to resolve in 3-5 days. If this is not the case you may want to have a recheck at your vet. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach. Best of luck.

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