Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
First, I would note that we do use Panacur as a 3 day dosing course, so I'd not suspect an overdose. Instead, I would note that if she had a lot of worms or is sensitive to this medication that could cause diarrhea for these wee ones. That aside, if she has diarrhea then we do need to tread with care. It is good that she is not feeling unwell, but we want to settle this as quickly as possible to avoid any risk of dehydration for her (since that is what makes them feel poorly).
In regards ***** ***** at this stage, we'd want to start by taking some supportive care steps to slow and settle her diarrhea. To start, we often will put them on a light or easily digestible diet. Examples would be cooked white rice with boiled chicken
, boiled white fish, scrambled egg, or meat baby food (as long as its free from garlic or onion powder). There are also veterinary prescription diets that can be used in cases of gastroenteritis (ie Hill’s I/D or Royal Canin’s sensitivity). Whichever you choose, the easily digestible diet will be better tolerated and absorbed by the compromised gut and should get some nutrients in and result in less diarrhea. Also feed this as small frequent meals to further decrease the volume of diarrhea she is producing. As long as improvement is being seen, I usually advise that the diet be continued until the diarrhea is settled, and that they are then slowly weaned back to their normal diet over a week.
Furthermore, since she is a little one and diarrhea can dehydrate a pup quite quickly, we do need to keep an eye on her drinking and hydration. To check her hydration status to make sure they are not becoming dehydrated there are a few things we can test. One is whether the eyes appear sunken, if the gums are tacky instead of wet/moist, and whether she has a "skin tent" when you lift the skin. To see how to check these parameters for dehydration, you can find a wee video on this HERE (http://www.ehow.com/video_12232503_dog-dehydrated.html). If you are seeing any signs of dehydration already, then you do want to have her seen by the vet before makes her feel poorly.
If you were concerned that she was becoming dehydrated, you can try and encourage her to drink but offering fresh water or even low-salt chicken broth. If she isn’t amenable to these, you can syringe feed pedialyte. Pedialyte is nice (though aim for a flavorless one) because it will get some of those lost electrolytes back into her as well. A typical maintenance rate for hydration in an animal is 48mls per kilogram of weight a day. If you do give syringe pedialyte, this should obviously be divided up into multiple offerings through the day rather then all at once. This value will give you the total she needs for the day and is a good starting point to give you an idea of a dog's daily requirement. (we aren’t calculating losses, so you can add an equivalent volume to match how much diarrhea is being producing). If she vomits when you have given pedialyte, then therapy should be discontinued (since we don’t want vomiting because of our intervention).
Further to this, as long as you have not seen blood in her stools, you can consider trying her today on a dog safe anti-diarrheals. As I am sure you appreciate, these would not be a cure if her diarrhea is being caused by an infectious agent and the wormer is a red herring. Still it can slow the diarrhea to aid the body to absorb more water/nutrients then it would have if the diarrhea were unchecked. In regards ***** ***** options for her, the one we most commonly use in dogs is Kaolin/Kaopectate (More Info/Dose @ http://www.petplace.com/article/drug-library/library/over-the-counter/kaolin-and-pectin-kapectolin-k-p). This is available from your local pharmacy. Furthermore, Propectalin, Fast Balance, or Protexin Pro-Fiber (which is available OTC at vets, pet stores, and even Amazon) would be another option. All will slow diarrhea and the last few have the bonus of providing support to the delicate good bacteria of the GI. So, you can consider trying these as a short term means of trying to soothe her upset GI.
Overall, while the wormer duration was an appropriate one, it is possible that this is a reaction to the drug working or a sign that she is sensitive to it. In any case, treating with supportive care for a few days should address that for her. Of course, if she doesn't settle with these, then something else may be lurking. If we were to see that, then we'd want to consider having a word with her vet (since she has just been seen) +/- submitting a fecal sample to see what may need to be treated. And should that be the case, then knowing what is there will allow you to treat to clear this and get her back to passing normal feces.
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best,