Page 77 - BSAVA Guide to Pain Management in Small Animal Practice

BSAVA Guide to Pain Management in Small Animal Practice

VetBooks.ir Serotonin toxicity continued with its peroxidase site, whose activity is
necessary for the cyclooxygenase site to
produce prostaglandins. Paracetamol is
reupta e inhi itors e.g. uo etine ,
monoamine oxidase inhibitors (e.g. generally more e ective in inhibiting C ,
selegiline) and tricyclic antidepressants and is anti in ammatory only in mild to
(e.g. amitriptyline). The syndrome moderate in ammatory states, when the
is characterized by clinical signs C pathway is activated in preference to
of autonomic hyper-reactivity, C 1 raham et al., 1 . In severe
neuromuscular signs and altered mental in ammatory states, where peroxidase levels
status (e.g. diarrhoea, tachycardia, are particularly high, paracetamol is less
hypertension, hyperthermia, tremor, e cient in inhibiting C . In this setting,
rigidity and seizures). The severity coxibs are more e ective, as their activity is
can range from mild clinical signs to peroxidase independent Anderson, 8 .
death. Treatment is mainly supportive Paracetamol, like NSAIDs, works both
and involves discontinuation of the centrally and peripherally inhibiting
inciting drug. prostaglandin synthesis, but its antinociceptive
e ects are also due to interference with the
serotoninergic, endogenous opioids, and
endocannabinoid systems. Interaction with the
Tapentodol nociceptive e ects of substance P and
glutamate has also been hypothesized
Tapentodol is a MOP agonist and noradrenaline raham et al., 1 . he only licensed
reuptake inhibitor, which has similarities to preparation of paracetamol contains
tramadol. It does not require metabolism to an paracetamol and codeine and is licensed for
active metabolite in humans, and it has minimal use in the dog only Pardale V, N A , 16 .
e ect on serotonin reuptake, which reduces the Although the Pardale-V datasheet states not to
risk of serotonin toxicity. It has been shown to use it with NSAIDs, paracetamol and NSAIDs
be antinociceptive in dogs in an experimental are often used in combination in human
study; in the same study tramadol showed no analgesia, and generic paracetamol
antinociceptive properties (Kogel et al., 14 . (intravenous or oral) is often combined with
However, oral bioavailability is poor in dogs NSAIDs in dogs.
iorgi et al., 1 and further research is
needed before recommendations regarding
clinical use can be made. The main advantage of paracetamol compared
One potential disadvantage of tapentodol is with conventional NSAIDs is its better
its legal category, which is a Schedule II gastrointestinal tolerance, and lesser
Controlled Drug in the UK. This means it must nephrotoxicity. The main metabolite of
be kept in a locked cupboard with detailed paracetamol in dogs is its glucuronide
records of its acquisition and use. conjugate, which is excreted in the urine. The
Paracetamol half life of paracetamol is only .96 hours in
the dog u anich, 1 , and experimental
Pharmacology studies failed to identify toxicity after
Paracetamol is a unique drug in that, while it administration of 1 mg kg Savides et al.,
does share similarities with NSAIDs, is not a 1984 . ue to impaired glucuronidation
strong anti in ammatory. Chemically, capabilities, cats rely on sulphate conjugation
paracetamol is a phenol, its protein binding is alone to eliminate paracetamol in the urine,
negligible, and it easily crosses cell resulting in an increased risk of toxicity.
membranes. Paracetamol inhibits Hepatic toxicity is mainly caused by a reactive
prostaglandin synthetase activity by interfering metabolite, which is conjugated with

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