“Also, do you think that adding Vitamin C will help with getting rid of her Giardia?”
It would be best to consult your vet before adding any supplements, you have already indicated that your dog needs pediatric dosages of medication due to her size.
Risks Associated with Vitamin C
Even promoters of vitamin C recognize the risk associated with too much vitamin C. Excess vitamin C is excreted through the kidneys, but too much can cause flatulence and diarrhea. This level varies with a dog’s age, size and breed.
Critics contend that feeding a healthy dog vitamin C is equivalent to feeding thyroid medication to a dog with a healthy thyroid and predict problems with the kidney and liver associated with vitamin C overdose.
The National Resource Council ran 24 tests on vitamin C in dogs in the 1980s, and all concluded that vitamin C should not be used to supplement a dog’s diet. One of the studies linked supplemental vitamin C with skeletal disease in Labrador retriever puppies. However, the the American Association of Feed Control Officials (AAFCO), designated the governing body for the pet food industry, labeled these tests invalid in 1994 on the basis that they are too old. (excerpt from https://www.vetinfo.com/vitamin-c-dogs.html)
