Q. We once had to have an elderly cat euthanized because of painful arthritis. The vet said there were no good long-term analgesics for cats. Why?

A. The treatment of pain in cats is more problematic than it is in people, or even in dogs, in part because it has been hard to develop pain-scoring systems for cats.

Long-term use of nonsteroidal anti-inflammatory drugs, or NSAIDs, can cause serious side effects, as in humans, including liver, kidney and intestinal problems. Acetaminophen in particular is toxic to cats and can be fatal.

Long-term corticosteroids also can lead to damage, including an increased susceptibility to infections, muscle weakness and Cushing’s disease. Opioids aren’t a good alternative, as they tend to produce mania in cats.

Some metabolic pathways that metabolize analgesic drugs in other animals are lacking in cats, which can lead to toxicity or lack of effect.