Actions of a Mixture of Amphetamine and a Barbiturate in Man

Abstract

The effects in man of a mixture of amphetamine and a barbiturate (15 mg of amphetamine sulphate and 300. mg of cyclobarbitone) and of each of the constituents separately were assessed on the performance of simple mental and motor tasks, on the pulse rate and on subjective reports. The mixture produced a pattern of effects which was different from that produced by either drug separately. It impaired the efficiency of the performance of tasks much less than did the barbiturate drug alone; it produced almost as big a rise in the pulse rate as did amphetamine alone; and it produced reports of feeling " elated " from many more subjects than did either drug separately, though there was no corresponding increase in reports of other feelings and sensations.

Differential Effects of Two Amphetamine‐barbiturate Mixtures in Man

“…This low dose of barbiturate was not studied by itself, but from other experiments (Nash, 1962) it seems unlikely that it would have any significant effects alone. The mixture which contained four times as much barbiturate, on the other hand produced some impairment of performances, though less than the constituent dose of barbiturate alone, and this confirmed previous findings (Legge & Steinberg, 1962). Like the first mixture and the control it produced reports of feeling " sociable," but otherwise the subjective effects were different.…”

“…There were few " desirable " effects, but a large proportion of subjects reported " undesirable " effects, for example that they felt dizzy, unsteady, drowsy and confused. Feelings suggesting " elation " which were prominent with this mixture in the previously reported study (Legge & Steinberg, 1962) were reported only fairly frequently by subjects in both the present mixture groups, and the effect only reached statistical significance in the Drinamyl-type mixture group as compared with cyclobarbitone alone. This may have been partly due to the different way of eliciting subjective sensations in the present investigation; the word " elated " did not seem a very natural one for the students to make use of.…”

“…Moreover, the Mixture300 group gave significantly more reports of " unsteadiness " than did all other groups. But these and the other human experiments referred to have, of necessity, been carried out with few dose combinations and manipulations of the experimental conditions, and this is also true of the clinical reports on amphetamine-barbiturate mixtures, both the earlier ones which have been listed in Legge & Steinberg (1962) and more recent clinical trials (Wheatley, 1962;Hare, McCance & McCormick, 1964). Aspects of their results might be worth following up, especially since there is now growing clinical interest both in drug mixtures in general and in ways in which effects of drugs can be modified by environment and personality (Rinkel, 1961;Hamilton, Hordern, Waldrop & Lofft, 1963;Steinberg, 1964;Lennard, 1965).…”

“…In a previous investigation (Legge & Steinberg, 1962) a mixture of 15 mg of amphetamine sulphate and 300 mg of cyclobarbitone and the two ingredients separately were studied in normal human subjects, and it was found that the mixture produced a different pattern of effects from the separate ingredients: it impaired the efficiency of the performance of three simple tasks less than did the barbiturate alone; it produced almost as big a rise in the pulse rate as did amphetamine alone; and it produced spontaneous reports suggesting " elation " from more subjects than did either drug separately, though there was no corresponding increase in reports of other feelings and sensations. The mixture used contained proportionally several times as much barbiturate as a widely used commercial preparation, Drinamyl (Smith, Kline & French), which contains dexamphetamine sulphate and amylobarbitone sodium in a ratio of 1: 6.5.…”

Differential effects of dexamphetamine and phenidylate on auditory detection

“…The effects of such drugs range from significant improvement of performance to significant impairment of performance, depending on the particular task and drug. Oexamphetarnine, for example, has been shown to improve performance on various mental and motor tasks, including pursuit·rotor tasks (payne & Moore, 1955), mathematical reasoning tasks (Nash, 1962;Legge & Steinberg, 1962), sustained work tasks (Kornetsky, 1959), as well as on a wide variety of more specific tasks (Nash, 1962;Payne & Hauty, 1954;Lehmann & Csank, 1957). However, accuracy of setting controls (Eysenck & Easterbrook, 1960), reaction time (Lehmann & Csank, 1957), and the accuracy of certain forms of judgment (Hauty & Payne, 1957) show a decrement in performance in response to dexamphetarnine administration.…”