Hi All a female Labrador age 14, off her food for a week and I called the Vet in? Vet diagnosed Osteoarthritis and started Labrador on Cartrophen? It is a injection, one injection a week for four weeks to complete the course and then a booster every six months. Cartrophen is a disease modifying drug for OA? Has anyone had any experience, good or bad of this treatment. What should I expect? What should I watch out for? I am totally in the dark here so any help would be most appreciative. Thanking you in anticipation.