Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that 15 year old Hank has a poor appetite and, despite your best efforts including given prescribed antibiotics, has refused to eat anything the past 2 days.The short answer is no, you cannot wait until Monday to have him re-evaluated and get a new game plan in order.His lethargy is very concerning. I am worried that your fellow is starving to death
. Dogs don't do that to themselves without good reasons behind it. His loss of appetite can be due to increased organ waste causing gastrointestinal irritation or by products of an infection suppressing his appetite or a mass taking up abdominal space and putting pressure on his stomach
and intestines such that he doesn't want to eat.I highly recommend that Hank see a veterinarian for another examination, complete blood count and biochemistry profile as well as a urinalysis and maybe abdominal radiographs or an ultrasound to diagnose his condition. Support measures in the meantime could include fluids to keep him hydrated and rebalance electrolytes and trace minerals in the body, which are certainly off if he isn't eating normally, and flush out any excess organ metabolites.The veterinarian can also prescribe an appetite stimulant such as mirtazapine to try to perk his appetite.To try and settle his stomach in cause he is nauseous and that is affecting his appetite you can give either:1) Pepcid ac (famotidine
) at a dose of one quarter of a 10mg tablet per 5 to 10 pounds of body weight every 12 hours OR2) Prilosec (omeprazole) at a dose of one quarter of a 20mg tablet per 10 to 20 pounds of body weight every 24 hours These are acid reducers and may help him feel less nauseous and hopefully improve his appetite. They are quite safe and can be used for several days if necessary. A couple hours after giving one of the acid reducers offer a bland diet of 1/3 boiled, minced, white skinless chicken
or boiled, lean hamburger and 2/3 boiled, white rice mixed with some low salt chicken or beef broth to make it easy to lap up and swallow and get additional fluids into him. If he refuses that, you can offer a little meat baby food. If he refuses both then don't push it, he needs hands on veterinary care as soon as possible. Best of luck with Hank, please let me know if you have any further questions.