Page 358 - The Veterinary Care of the Horse

Symptoms of toxicity include anorexia, weight loss, diarrhoea and anaemia. However, side

effects are uncommon if the drugs are used at recommended levels. They are more likely to
VetBooks.ir be seen in ponies, foals and older, debilitated or dehydrated animals.

There is also concern that with long-term use, some NSAIDs have a detrimental effect on
cartilage metabolism. Others may have a protective effect. There is much research going on

in this area at present and it is hoped that, as a result, new drugs will be developed to
overcome these problems.

The use of NSAIDs should be combined with a programme of regular, light work. If the
work is strenuous and intermittent, the joint changes may be accelerated.

PENTOSAN POLYSULFATE SODIUM (CARTROPHEN)

This medication is administered by intramuscular injection on four occasions at intervals of
5–7 days. It stimulates stem cell activity and chondrocyte differentiation and increases the

blood supply and nutrition to the joint and subchondral bone. It is claimed to stimulate
growth factors that encourage cartilage production and to improve the quality and quantity of
synovial fluid. It has an anti-inflammatory action and inhibits cartilage-degrading enzymes.

At the time of writing pentosan polysulfate is not licensed for use in the UK but can be

obtained for individual cases with a Special Import Licence.

POLYSULFATED GLYCOSAMINOGLYCANS (ADEQUAN)

This product is chemically similar to a constituent of articular cartilage. It suppresses

inflammation and inhibits enzymes that break down articular cartilage and bone. The
intramuscular preparation is given every 4 days for seven treatments; in the United States it is
approved for non-infectious degenerative joint disease of the knee and hock. An intra-

articular preparation is used for non-infectious problems of the horse’s knee and is given
once a week for 5 weeks. At the time of writing these preparations are not available in the

UK.

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BISPHOSPHONATES (Equidronate , Tildren , Osphos )
Healthy bone throughout the body is constantly being remodelled by osteoclasts, which
resorb bone, and osteoblasts that lay down bone in response to mechanical stresses that the
horse’s body is subjected to. In certain situations such as navicular disease and distal hock

joint arthritis (bone spavin) the osteoclasts show increased activity and too much resorption
occurs causing lesions to form in the bone. This class of drug works by inhibiting the

resorption process by osteoclasts and may lead to a reduction in pain experienced by the
horse.