You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

It is now well recognised that external behavioural responses alone can not be relied upon as an indicator of the presence of pain in human cancer patients. The same is undoubtedly true in veterinary patients. Should the veterinary profession therefore adopt the World Health Organisation's recommendations for treating pain in human cancer patients ?

Over the past decade the importance of animal welfare in general, and the need to identify and relieve stress and pain in particular, have received a lot of attention from the veterinary profession. Because veterinary patients can not verbally describe the effects of analgesics that we administer in relieving their pain we are left to assess their efficacy from behavioural signs alone. Until we have non-invasive, non-painful, objective methods for monitoring pain and it's response to analgesics perhaps we should adopt a rational approach to pain management, such as that advocated for use in humans by the WHO ?

Basically, there are 3 stages to the WHO recommendations :

Stage 1

Manage pain with non-steroidal anti-inflammatory drugs (NSAIDs) alone. Humans are usually started on a low dose and gradually increased to a maximum of 1.5-2 times the standard recommended dose.

• Reported to be effective for human bone cancer patients
• Many patients (including dogs) develop gastric ulceration with these drugs, so the concurrent use of H₂ - receptor blockers, antacids or misoprostil should be considered 
• Some of these drugs are risky to give to old animals which may have frank or sub-clinical renal disease as they may precipitate acute renal failure. 
• Acetaminophen (paracetamol) - which is widely used in human cancer patients - is contraindicated in patients with impaired liver function and in cats.

Stage 2

If pain is not adequately controlled with NSAIDs alone an oral "weak" opioid is administered in addition :

• Examples : codeine, propoxyphene, oxycodone, hydrocodone, dihydrocodeine
• Some of these are available only in combination with acetaminophen or aspirin.

Stage 3

Patients with severe cancer pain, or those that do not respond to Stage 2 regimen of drug therapy are given opioids with or without NSAIDs

• Morphine, fentanyl
• These drugs are subject to the Misuse of Drugs Regulations 1985

CLICK HERE for a Table of analgesics that are available in the UK for use in canine and feline cancer patients

Updated January 2016