Hello, my name isXXXXX and I have over 20 years of experience as a veterinarian.
I am sorry to hear that Harvey is lame on his front leg.
If he has any obvious swollen areas, has any change in appetite or is running a fever (more then 39.4C rectally) then he should see his veterinarian. We need to be concerned about infection or a possible tumor in an oder fellow with those sorts of symptoms.
Ideally he would see his veterinarian because the prescription medication your veterinarian has for pain and inflammation will be much safer and work better than any over the counter medications that we take. In fact acetaminophen and ibuprofen aren't used in dogs because their effective doses are very close to a toxic dose in dogs.
The only over the counter anti-inflammatory that can be used in dogs is buffered, enteric coated aspirin (like ascriptin). Aspirin does cause stomach and intestinal irritation and ulceration as well as clotting problems so should not be given for more than 2 to 3 days consecutively and should always be given with a meal. If you choose to use it watch for lack of appetite, vomiting, blood in the stools or dark tarry stools and stop immediately if you see those. Do not use aspirin if your dog has liver or kidney disease or a history of a sensitive stomach or clotting problems.
The dose for aspirin is 10mg per kilogram orally every 12 hours (about one 325mg buffered, enteric coated aspirin for a 27 kilogram dog every 12 hours). Always give with a meal. Do not use for more than 2 or 3 days.
Be aware if you choose to use aspirin and it doesn't help your veterinarian will be limited on what they can give as there must be a 5 to 7 day washout period between different nonsteroidals or nonsteroidals and steroids.
You can try alternating warm and cold packs on his painful area for 10 minutes at a time several times a day.
Make sure to rest him for at least 6 weeks, no running , stairs or jumping.
Long term for joint pain I do recommend using a combination of aglucosamine/chondroitin product (examples are Dasuquin or Cosequin) and anomega 3 fatty acid (like 3V Caps or Derm Caps). I recommend an omega 3 dsoe beased upon the EPA portion (eicosapentanoic acid) the supplement as if we do that the rest of the supplement will be properly balanced. Give him 20mg to 40 mg of EPA per kilogram of body weight per day. These work synergistically andimprove cartilage health and joint fluid quality and quantity as well as reducing inflammation. They can take several weeks to see full improvement but some dogs do very well with them alone. They are available over the counter.
Another option is a product called Duralactin. This is an anti-inflammatory product derived from milk proteins and it also has omega 3 fatty acids incorporated into it which can be very helpful. See this link for further information: http://www.duralactin.com/products_canine.htm
If that's not enough or you do notice any swollen areas on his leg he should see his veterinarian for prescription drugs that are more potent. Veterinary drugs we can add include a nonsteroidal like Metacam, Deramaxx, Previcox or Rimadyl. If those aren't enough we can add another drug in the opiod family called Tramadol and/or another drug called Gabapentin. These drugs are much safer and more effective than aspirin. Aspirin used for any length of time will create gastrointestinal ulcers and clotting problems.
Best of luck with your fellow, please let me know if you have any further questions.