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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?

2 Answers

Most Helpful Answer

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.

1Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Stacey Anstaett, DVM
Veterinarian
Published on January 10th, 2020
I would still give him his pills, but give him just enough food to give the pills-- use something bland such as white bread to hide the pills in. I cannot directly tell you to give the metronidazole, as I am not the dr who prescribed it, and a valid "veterinarian-client-patient" relationship is needed in order for me to direct you regarding medications. Having said that, you can call the vet who prescribed it previously and run it by them; I suspect they may suggest you go ahead and start the metronidazole while fasting if there's been some bloody diarrhea. Again, you can give it with a little bland food. After 24 hours, when you start feeding him again, feed a bland diet such as boiled chicken and white rice for a few days.
If he's not improving in 2-3 days or if any additional symptoms develop (vomiting, lethargy, etc) please take him to a vet if at all possible.
Thank you for asking Petco Pet Education Center, formerly Petcoach!
1Pet Parents found this answer helpful

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