I Am Checking The Drug Safety Interactions From Several RX's

I am checking the drug safety interactions from several RX's prescribed to my dog (80 lb). has a gastro/intestinal infection from outdoor contact. (deer droppings, possibly standing water, loss of appetite, blood in stools, diarrhea. List of Meds: Metronidazole (500mg/every 12 hours/10 days. Cerenia 1 injection, and oral tablet 160 mg/1/2 tab every 24 hours 3-4 days, Famotidine, 1 injection on 11-3-15, Omeprazole/20mg, 2 tablets daily for 10 days. Tramadol/50 mg/3 tablets every 12 hours (using 2 tablets only). All are vetrinary prescribed.