A COMPARISON OF THE EFFECTS OF ORALLY ADMINISTERED BARBITURATE SALTS AND BARBITURATE ACIDS ON HUMAN PSYCHOMOTOR PERFORMANCE

¹ Departments of Medicine (Division of Clinical Pharmacology) and of Pharmacology and Experimental Therapeutics, Johns Hopkins University School of Medicine, Baltimore, Maryland

In a double-blind study of 41 healthy volunteer subjects, the sodium salts of phenobarbital and of secobarbital (in 150-mg doses) were found to produce more rapid and more profound impairment of performance on a variety of tests than the corresponding acid forms. Phenobarbital sodium was found to cause a significantly greater deterioration in performance than phenobarbital acid on the tests of arithmetic and 30-sec tapping at hr after drug administration. Secobarbital sodium produced more impairment of performance than did secobarbital acid at hr on the arithmetic test and at hr on the coding test. No significant differences were found at hr on the other tests, but for both barbiturates the differences between groups were in the direction of greater impairment of performance with the salt than with the acid form. For the entire 3-hr testing period, phenobarbital sodium produced significantly more impairment of performance than did the acid form on the arithmetic test, and secobarbital sodium produced significantly greater impairment than the acid form on the tests of coding and arithmetic. On the other tests, differences between the acid and salt forms of the drugs were nonsignificant but in the same direction. Subjectively, those receiving sodium phenobarbital were able to detect that they had received a barbiturate earlier than those receiving the acid form. No such difference was found for secobarbital. A questionnaire filled out at home suggested that subjects receiving phenobarbital acid were most likely to have "hang-over" the next morning. The basis for the observed differences between acids and salts in speed of action is presumably more rapid absorption of the salt form from the gastrointestinal tract.

This article has been cited by other articles:

				L. Lasagna The Pharmaceutical Revolution: Its Impact on Science and Society Science, December 5, 1969; 166(3910): 1227 - 1233. [PDF]