Toxicity of β-diethylaminoethyl diphenylpropylacetate (SKF-525A) in cats

In unanesthetized cats, intravenous injection of 5–10 mg/kg of β-diethylaminoethyl diphenylpropylacetate (SKF-525A) produced respiratory and gastrointestinal disturbances. A dose of 25 mg/kg caused clonic convulsions and death. Larger doses of SKF-525A were tolerated by intraportal and intraperitoneal administration, but effects of repeated injections were cumulative and progressed to anorexia, convulsions, and death within 48 hours. In anesthetized cats, observations were made upon blood pressure, respiration, end-expiratory pCO 2, electrical excitability of the respiratory center, and transmission through the superior cervical sympathetic ganglion. The chief effects of intravenous injection were shortlasting noncholinergic peripheral vasodilatation and persistent respiratory depression. Intracarotid injection evoked a prompt vasopressor response and concomitant skeletal muscle movements due to stimulation of the forebrain. Intravertebral injection resulted in rapid depression of the respiratory center in the lower brainstem. The drug effects elicited in unanesthetized cats are explained by the combination of central and peripheral effects of SKF-525A observed in anesthetized cats.