Adequan is an injectable medication for the treatment of osteoarthritis in dogs. It is a disease-modifying osteoarthritis drug (DMOAD), meaning it can reverse some of the damage that occurs in arthritic joints.
Adequan contains polysulfated glycosaminoglycan (PSGAG), which has been shown to inhibit catabolic enzymes that contribute to the destruction of cartilage in arthritic joints. PSGAG has also been shown to stimulate the production of anabolic enzymes. Anabolic enzymes promote cartilage repair and enhance the quality of synovial fluid in arthritic joints.
So, what exactly does this mean for dogs suffering from osteoarthritis? Let’s take a look at the basic structure of joints to get a better understanding of how Adequan works.
Understanding Canine Joint Structure and Osteoarthritis
A joint is the junction of two or more bones that allows movement, such as the back-and-forth movement of the knee. The ends of the bones are capped with a smooth, glistening substance called cartilage. Think about the last time you ate a chicken wing (or watched someone else eat a chicken wing, if you don’t eat meat). That smooth white cap on the end of the chicken wing bone is cartilage.
Cartilage protects the ends of the bones from damage and provides a smooth surface for movement of the joint. The ends of the bones are connected by ligaments—strong, fibrous bands of tissue that keep the joint aligned and prevent it from moving in inappropriate ways.
The joint is surrounded by an envelope of fibrous tissue called a joint capsule. The joint capsule creates a sealed space around the joint which is filled with synovial fluid. Synovial fluid is produced by cells that line the inside of the joint capsule. It is viscous (thick) so that it can provide shock absorption within the joint and lubricates the joint to keep everything moving smoothly.
Cartilage requires nutrition and oxygen to perform its functions. Blood is the primary source of oxygen and nutrients in the body. Cartilage does not contain any blood vessels and therefore has no direct source of nutrition and oxygen. It can obtain some of these vital ingredients from blood vessels in the ends of the bones the cartilage covers. However, most of its nutritional needs are met by absorbing oxygen and nutrients from synovial fluid within the joint.
Joints affected by osteoarthritis experience inflammation and degradation of cartilage. Inflamed cartilage releases catabolic enzymes which cause further degradation of the damaged cartilage. This turns into a vicious cycle of inflammation and degradation that makes cartilage thin and brittle.
Bones that are capped by thin and brittle cartilage do not have the same protection as those covered by thick, healthy cartilage. Bones that do not have adequate protection within joints become damaged and painful. Adequan slows the progression of osteoarthritis and improves joint health.
How Adequan Works
Adequan inhibits the production of catabolic enzymes in inflamed joint cartilage. Catabolic enzymes destroy molecules that are necessary for maintaining healthy joints. These molecules include:
- Proteoglycan—an important building block of cartilage.
- Collagen—this structural protein is the basis for cartilage, ligaments, and tendons.
- Hyaluronic acid—a lubricant in synovial fluid.
Adequan also enhances the activity of anabolic enzymes inside joints. Anabolic enzymes stimulate production of collagen, proteoglycans, and hyaluronic acid. These are necessary to repair damaged cartilage and keep synovial fluid happy and healthy. Adequan has also been shown to reduce inflammation in arthritic joints.
Treating a Dog with Adequan
Adequan can be an effective part of a multi-modal therapeutic plan for the treatment of osteoarthritis in dogs. It is administered by intramuscular injection and, once injected, it moves from the muscle into the bloodstream. Then it passes from the bloodstream into each joint’s synovial fluid. Joint cartilage absorbs Adequan from the synovial fluid.
Adequan is given twice a week for four weeks for a total of eight doses. Peak concentration of Adequan in the bloodstream is achieved about 20 to 40 minutes following intramuscular injection. It takes about two days for Adequan to reach peak concentration in synovial fluid. Adequan persists at peak concentration in the joints for an additional three days.
The concentration of Adequan in synovial fluid and cartilage will be higher than that found in the bloodstream once the series of injections has been completed. Cartilage damaged by osteoarthritis will take up more Adequan than joints unaffected by osteoarthritis.
Adequan is only indicated for the treatment of non-infectious arthritis and degenerative joint disease. It is not for use in dogs with septic or infectious arthritis.
Side Effects of Adequan
The most common side effect of Adequan is pain at the injection site. Other side effects are transient and include vomiting, diarrhea, and decreased appetite. These side effects typically resolve quickly and without intervention.
Adequan shares structural similarities with a compound called heparin. Heparin is an anticoagulant that is used to prevent formation of clots in the bloodstream. Abnormal bleeding in the first 12 hours after administration of Adequan is rare but has been reported. Adequan should be used with caution in dogs that have a bleeding disorder.
Adequan for Dogs: Cost and Dosage
Adequan is purchased by the vial and is dosed by a dog’s weight. Bigger dogs require a larger Adequan dose than smaller dogs. Therefore, it costs more to treat a bigger dog with Adequan.
Adequan is the only FDA-approved DMOAD available in the United States. Cartrophen is a DMOAD that is available in other parts of the world, including Canada, Australia, and Europe. Do not confuse Cartrophen with the non-steroidal anti-inflammatory drug (NSAID) called carprofen (also known by the brand name Rimadyl).
