Abstract
The present investigation is concerned with the influence of antipyretics on digitalis. The antipyretics investigated were: the salicylates, acetanilid, phenacetin, aminopyrine, aspirin and antipyrine.
Dogs are quite sensitive and uniform in their reaction to digitalis. The average fatal dose of the tincture of digitalis, injected intravenously at the rate of 0.1 cc. per kilo body weight every 5 minutes, is 1.2 cc. per kilo, when dogs are anesthetized with 35 mg. of pentobarbital per kilo intraperitoneally. In previous work it was shown that high body temperature does not prevent the action of digitalis nor influence its toxicity. The variation from this fatal dose is surprisingly small. Therefore, the effect of the various antipyretics in changing the fatal dose of digitalis was tested.
In this report the point to which we wish to draw attention is the astounding effect on blood pressure which is effected by digitalis after all antipyretics. We select in this case antipyrine as the type.
I. Dog-23.3 kg., female; normal Mood pressure 150 mm. Ten equal doses of 10% antipyrine were injected intravenously, making a total dose of 100 mg. per kg. The blood pressure after the antipyrine had been given was 130. At this point, digitalis was started in doses of 0.1 CC. per kg. The pressure rose gradually to 170 after 6 injections of digitalis. At this point the pressure rose sharply to 210, and, after another injection, it went to 300. The pressure was actually higher than this, as our manometer was incapable of recording a higher figure. After one more injection the dog died. The total dose of digitalis was 0.8 cc. per kg., as compared to a normal lethal dose of 1.2 cc. per kg.
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