For treatment of Giardia:
a) 15–25 mg/kg PO q12–24h daily for 5–7 days (Lappin 2006)
b) 22 mg/kg PO twice daily for 5 days. May be combined with fenbendazole (50 mg/kg PO once daily for 3 or 5 days) to relieve clinical signs and eliminate parasites. (Payne & Artzer 2009)
For other protozoal infections:
a) Entamoeba histolytica or Pentatrichomas hominis: 25 mg/kg PO q12h for 8 days (Lappin 2000)
For anaerobic infections:
a) For sepsis: 15 mg/kg IV q12h (Hardie 2000)
For eliminating Helicobacter gastritis infections:
a) Using triple therapy: Metronidazole 15.4 mg/kg q8h, amoxicillin 11 mg/kg q8h and bismuth subsalicylate (original Pepto-Bismol®) 0.22 mL/kg PO q4–6h. Give each for 3 weeks. (Hall 2000)
For adjunctive therapy of plasmacytic/lymphocytic enteritis:
a) 10–30 mg/kg PO q8–24h for 2–4 weeks in refractory cases (Leib, M.S. et al. 1989)
For Clostridium perfringens enterotoxicosis:
a) 10–20 mg/kg PO twice daily for 7–28 days. (Tams 2007)
For inflammatory bowel disease:
a) 10–20 mg/kg PO two to three times a day has been used in the treatment of mild to moderate cases of large bowel IBD. (Washabau 2009)
b) For ulcerative colitis in dogs refractory to other therapies (e.g., sulfasalazine, immunosuppressants, diet, etc.): 10–20 mg/kg PO twice daily–three times a day; may be beneficial in treating for 2–4 weeks those dogs with chronic colitis having unexplained diarrhea (Leib, M. 2000).
c) 10–15 mg/kg PO q8–12h; combine with prednisone to manage moderate to severe cases. (Marks 2007)
d) In cases of predominantly large bowel diarrhea (colitis with typical clinical presentation) if parasiticide treatment and elimination diet fail, a therapeutic trial can be made: metronidazole 20–25 mg/kg PO twice daily for 5-10 days with the addition of fiber to the diet (e.g., psyllium at 0.5 tablespoon for toy breeds, 1 tablespoon for small dogs, 2 tablespoons for medium dogs, and 3 tablespoons for large dogs. However, sampling of mucosal biopsies prior to further treatment may be the best course of action. (Gaschen 2008)
For treatment of medial canthus syndrome (tear staining):
a) 100–200 mg (total dose) PO once per day for 10 days each month.(Krohne 2008)