What is the best arthritis medicine for dogs?

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
Analgesic medications that relieve arthritis pain, such as Rimadyl, Deramaxx, and Novox are NSAIDs, nonsteroidal anti-inflammatory drugs. NSAIDs revive the spirits of pets by resolving their pain. They work quickly to decrease prostaglandins that cause pain, and this allows pets to move easily and to exercise. When pets are able to exercise, their hearts, lungs, and digestive systems continue to function normally. When arthritic pets are able to exercise, it helps to maintain their muscle strength. This process helps hold their joints in correct alignment, which reduces the amount of pain.
As with most things in nature, any medicine that can cause so much good has the potential to cause harm. To prevent harm, most NSAIDs require a veterinarian’s prescription. The veterinarian will request blood tests to confirm the NSAIDs have not damaged the stomach, liver, or kidneys. Some veterinarians recommend using Omega 3 fatty acids, such as those found in Super Pure Omega 3 and Nordic Naturals Omega-3 Pet to protect the kidney, and using Denosyl to protect the liver. DO NOT GIVE NSAIDS TO CATS.

Corticosteroids are naturally produced in small amounts in all warm-blooded creatures, including people and pets. Pharmaceutical corticosteroids mimic natural steroids, but are in a much higher concentration. They are best used for emergency rather than chronic treatment of painful conditions, including arthritis. Because corticosteroids have serious side effects, they require a prescription, and your veterinarian may request periodic blood tests to confirm that the liver remains healthy. Some veterinarians will recommend supplementing with Denosyl to protect the liver. Some of the top-selling prescription corticosteroids are Prednisone, Prednisolone and Triamcinolone.

Supplements for dogs and cats with arthritis
Glucosamine and chondroitin supplements
Research has proven that pets develop arthritis much more slowly if they receive joint supplements in their youth, and throughout their lives. Supplements nourish and protect joint cartilage which often helps pets with arthritis experience less pain. Look for supplements that contain glucosamine and chondroitin which are considered the best joint nutrition available; they help joint cartilage stay moist and lubricated, and stimulate joint cells to make repairs if damage has occurred. Studies also confirm that glucosamine and chondroitin alleviate stiffness and pain. Because they actually change the joint, it takes 1-2 months before improvement is obvious. Unlike nonsteroidal anti-inflammatory pain medications (NSAIDs), they do not cause kidney or liver damage.
In fact, some research suggests they protect the body from NSAID damage. Examples of excellent supplements that protect cartilage (chondroprotectives) include Super Joint Enhancer and Dasuquin. These products help make the joint healthier. We recommend that pets begin receiving condroprotective supplements when they are young to reduce the odds of developing joint damage throughout their lives.
Omega 3 fatty acid supplements
Inflammation occurs with arthritis in cats and dogs, and Omega 3 fatty acids are proven to reduce swelling, heat, and pain that characterize inflammation. Because Omega 3 fatty acids reduce inflammation, if your pet is taking them and your pet injures a joint, they may sustain less joint damage than they would have if your pet was not receiving them. In addition to benefiting the joints, fatty acids have been proven to benefit the brain, learning and behavior, the skin, kidneys, and other internal organs.
Homeopathic remedies for arthritis
Homeopathics help many pets with arthritis. T-Relief Tablets are especially useful for dogs and cats (also for birds and horses) with arthritis or acute joint pain as a result of trauma. Given shortly after injury, Traumeel helps reduce long-term damage. Traumeel is especially useful for pets with fragile stomachs, kidneys or livers who should not take NSAIDs. It benefits pets whether the damage is to bone, muscle, ligament or tendon.