Mechanism of action
Caffeine is a methylxanthine and exerts its effect through several mechanisms. It enhances catecholamines release, antagonizes cellular adenosine receptors and inhibits cellular phosphodiesterases thereby increasing intracellular cyclic AMP (AMPc) and calcium influx. Ephedrine is a sympathomimetic alkaloid with α-, β1- and β2-adrenergic agonist activity and CNS stimulatory effect.
Clinical presentation
Accidental ingestion of this herbal supplement has been reported to result in vomiting, hyperactivity, tachycardia, hyperthermia, mydriasis, muscle tremors, behaviour changes and seizures in dogs (Ooms et al., 2001).
Diagnosis
The clinical diagnosis can be supported by detection of caffeine or ephedrine alkaloid in the urine.
Management
Treatment includes decontamination, AEMs (see Table 4.1 and Chapters 12 and 24) and supportive care (including fluid therapy to enhance diuresis and toxin excretion). The use of benzodiazepines is not recommended in pseudoephedrine toxicosis as it has been reported to cause exacerbation of clinical signs.
Prognosis
Most dogs recover with prompt treatment; however, this intoxication can be fatal (Ooms et al., 2001).
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