Dr. Marie replied:

Hmmm...this is a tough one because I can't really see a connection here.

Frontline and Heartgard are perfectly safe to use together. They shouldn't cause a dog to be lethargic.

It is possible for a dog to be lethargic after vaccines, but it's not that common. And, usually if there is some sort of reaction it happens within 24 hours.

I'm guessing that there could be something going on that is not connected to the vaccines.

If Angel is eating and drinking her normal amount then I would likely just keep an eye on her for now and if she is still like this when your vet opens on Monday then I would give them a call.

There are a number of other things that could be going on. If it is very warm in your area then this could be affecting her. Or perhaps she has some pain somewhere such as her back. It's often tough to know though!

I have had some dogs where a vaccination was "the last straw" in an illness. So, let's say she was fighting an age related condition like kidney disease or liver disease. When the vaccine challenged her immune system then this could have caused the disease condition to get worse.

Again, if she is eating and drinking ok I would likely wait till Monday. The exception, of course, is if your gut is just telling you that she is really unwell.

Please let me know if you have more questions.
Dr. Marie.

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Dr. Marie replied:

You're very welcome. I hope everything is ok.