Ultra-Short-Acting Thiobarbituric Acids

Abstract

Summary

Four N-methyl thiobarbituric acids have been studied and compared with sodium 5-allyl-5-(1-methylbutyl) thiobarbitu-rate and thiopental in rats, rabbits, cats, and dogs. They are all potent anesthetics by intravenous injection. The N-methylated derivatives, in an observed AD⁶⁰ duration of anesthetic and hypnotic action than the 2 non-methylated compounds. When one-half of AD⁵⁰ is intravenously injected at hourly intervals, all 4 N-methyl-substituted barbiturates show less cumulative action than sodium 5-allyl-5-(1-methylbutyl) thiobarbiturate and still less than thiopental. In anesthetized cats, 2 of the N-methyl barbiturates produce less hiccup, sneezing, and coughing than sodium 5-allyl-5-(1-methylbutyl) thiobarbiturate and thiopental, while the 2 others are free from such effects. Like all barbiturates, the 4 N-methylated compounds, when injected intravenously in anesthetized dogs, lower the blood pressure and depress respiration. They do not inhibit the vagal response in these preparations. They induce slight hypothermia and tachycardia in dogs following an AD⁵⁰ of each product.

The authors are indebted to Misses Eva Sommermeyer and Marion Ellaby, and to Messrs. William R. Gibson. Wallace C. Wood, James E. Waddell, E. Brown Robbins, and Lester Le Compte for their invaluable assistance in this work.