Comparative Protective Efficiency of Some Barbitals Against the Symptoms of Anaphylactic Shock

Abstract

It is well known that certain depressants of the central nervous system are effective in preventing fatal anaphylactic shock. Many of them, however, would not be as good protective agents against the symptoms of shock in sensitized individuals as would certain hypnotics. We have, therefore tried out the efficiency of some of the barbitals for this purpose. Three representative members of this group were selected for study: amytal, phenobarbital, and barbital. The experimental evidence here recorded supports the conclusion that phenobarbital alone possesses a highly protective efficiency against the symptoms of anaphylactic shock. Experiments were carried out on 61 animals divided as follows: 14 controls, 10 injected with amytal, 14 with barbital, and 23 with phenobarbital. Guinea pigs weighing 250 to 300 gm. were sensitized by the intraperitoneal injection of 1 cc. horse serum. After an incubation period of 2 to 3 weeks, an intracardiac injection of a second dose of serum usually produced typical anaphylactic shock with rigid distention of the lungs in about 86% of the controls. These control observations as well as those recorded in previous communications,, have satisfied us that the intraperitoneal route for sensitization and the intracardiac route for shock injections give a high percentage of positive results. The sodium salts of the barbitals were administered intramuscularly: amytal from 50 to 70 mg., barbital 80 to 200 mg., and phenobarbital 40 mg., per kilo of body weight. These doses were found to be nonfatal and definitely depressant for guinea pigs, though very large compared to single therapeutic doses in man. The effects produced corresponded to the ordinary hypnotic action of the drugs with more marked depression and some anesthetic effect in animals given daily injections of amytal and the larger doses of barbital.