My 16 month old German Shepherd was recently diagnosed with Giardia through a fecal test. He was on medication which helped and then my veterinarian prescribed a de-wormer. Now his diarrhea is worse than ever and he has thrown up twice. This has lasted for almost a week since the deworming. Could this just be residual symptoms from the parasite leaving his system and all the medications upsetting his stomach or is something still wrong?
Giardia is a common intestinal infection in dogs that causes diarrhea or, in many cases, no signs of illness at all. Treatment with antibiotics and dewormers is safe, but not always immediately efficacious. Some dogs require longer courses of treatment to test 'negative' for Giardia on a repeat fecal exam, so it is important to follow-up with your veterinarian until a negative test is achieved. However, vomiting is not typically associated with Giardia or the medications used to treat it. I would definitely recommend additional diagnostics, including bloodwork, x-rays, or an abdominal ultrasound if your dog is feeling sicker since beginning treatment, as this could indicate that another illness is present.