Changes

Oxidisation is the main method of aspirin metabolisation, but some drug is also conjugated to glucuronide. Glucuronidation cannot be performed by the cat, accounting for the long half-life in this species.

Oxidisation is the main method of aspirin metabolisation, but some drug is also conjugated to glucuronide. Glucuronidation cannot be performed by the cat, accounting for the long half-life in this species.

===Paracetemol===

===Paracetamol===

Although paracetemol is rarely used in veterinary medicine, it is a common household drug and so problems may arise following owner administration.

Although paracetamol is rarely used in veterinary medicine, it is a common household drug and so problems may arise following owner administration.

Paracetemol is metabolised by three liver pathways: glucuronidation, sulphate conjugation and N-hydroxylation. N-hydroxylation produces a substance known as NABQI which binds glutathione. If glutathione binding is saturated, NABQI binds hepatic proteins and thereby leads to liver necrosis. The glucuronidation pathway is absent in the cat, meaning N-hydroxylation is used as an alternative. Relatively, this produces greater quantities of NABQI making glutathione saturation more probable. Cats are therefore more susceptible to paracetemol toxicity. Paracetemol toxicity may be treated with N-acetylcysteine, a glutathione precursor.

Paracetamol is metabolised by three liver pathways: glucuronidation, sulphate conjugation and N-hydroxylation. N-hydroxylation produces a substance known as NABQI which binds glutathione. If glutathione binding is saturated, NABQI binds hepatic proteins and thereby leads to liver necrosis. The glucuronidation pathway is absent in the cat, meaning N-hydroxylation is used as an alternative. Relatively, this produces greater quantities of NABQI making glutathione saturation more probable. Cats are therefore more susceptible to paracetamol toxicity. Paracetamol toxicity may be treated with N-acetylcysteine, a glutathione precursor.

Paracetemol is grouped as an NSAID, but actually has an alternative mechanism of action. It interferes with cyclic endoperoxidases, the intermediate stage of inflammatory mediator formation. Thus, it acts further down the pathway of mediator production and so has a narrower range of effects than other NSAIDs. The drug has good anti-pyretic and analgesic properties, but is inferior as an anti-inflammatory.

Paracetamol is grouped as an NSAID, but actually has an alternative mechanism of action. It interferes with cyclic endoperoxidases, the intermediate stage of inflammatory mediator formation. Thus, it acts further down the pathway of mediator production and so has a narrower range of effects than other NSAIDs. The drug has good anti-pyretic and analgesic properties, but is inferior as an anti-inflammatory.

Pardale-V is a preparation of paracetemol with codeine which is licensed in dogs (although not for long-term use). It has fewer gastro-intestinal side effects than other NSAIDs and is therefore good for animals which are particularly sensitve to these drugs.

Pardale-V is a preparation of paracetamol with codeine which is licensed in dogs (although not for long-term use). It has fewer gastro-intestinal side effects than other NSAIDs and is therefore good for animals which are particularly sensitve to these drugs.

===Phenylbutazone===

===Phenylbutazone===