Welcome to Justanswer! I am Dr. Altman and happy to assist you both today!
At 110 pounds (50 kg) this ingestion of 600 mg would mean that the concentration ingested was 12 mg/kg. According to the veterinary formula:
There is little data available regarding this drug’s acute toxicity. A 14-day study in dogs demonstrated no clinically observable adverse effects in the dogs that received 10 mg/kg. Dogs that received 25 mg/kg, 50 mg/kg or 100 mg/kg per day for 10 - 11 days survived, but showed vomiting and melena; no hepatic (liver) or renal (kidney) lesions were demonstrated in these dogs.
In safety studies performed by the drug manufacturer (Roberts et al. 2009) , oral deracoxib was well tolerated by dogs when administered for up to six months at a variety of doses. Some dogs receiving >6 mg/kg/day (1.5-5X) showed signs of focal tubular degeneration/regeneration(kidney) on histopathology. Focal tubular necrosis was seen in 4 dogs (of a total of 20) when dosed at 8 mg/kg/day (1 of 10 dogs) or 10 mg/kg/day (3 of 10 dogs) in the 6-month safety study. Again this is a longterm study not an acute one of one time ingestion
There were 979 exposures to deracoxib reported to the ASPCA Animal Poison Control Center (APCC) during 2008-2009. In these cases
948 were dogs with 96 showing clinical signs and the remaining 31 cases were cats with 1 showing clinical signs. Common findings in dogs (recorded in decreasing frequency) include vomiting, diarrhea, lethargy, and elevated creatinine.
Because non-linear elimination occurs in dogs at dosages of 10 mg/kg and above, dogs acutely ingesting dosages above this amount should be observed for gastrointestinal erosion or ulceration and treated symptomatically for vomiting and GI bleeding. So these are the symptoms to be monitoring for the next 24-48 hours for your Lab
I hope this information makes sense but if it is confusing please don't hesitate to ask additional questions. Monitoring for gi upset for the next few days is key along with feeding a bland diet of white rice and lean boiled meat. If you want to be proactive I would advise having your veterinarian run a basic kidney and liver profile to ensure there are no complications that might show up later (>48 hours) associated with organ function but unlikely at this one time dose
Please let me know how else I can assist you both today
If you have more questions or if I can help in any other way, please do not hesitate to ask! If you would like to accept my answer, please press RATE OUR CONVERSATION at the top of your screen (I am not compensated in any other way). Bonuses are always welcome. Thanks!