The alleged sedative effect of thonzylamine hydrochloride (neoheteramine).

Abstract

T HAT there are wide differences among the various antihistaminic agents with respect to potency and duration of action is well known. That qualitalive and quantitative differences exist in undesirable side effects, particularl) sedat,ion, produced by these various agents seems equally probable. That is, agents having a common therapeutic result usually differ widely in potency! duration and side effects. However, the entire group of antihistamines are frequently said to produce more or less sedation in many patients. For example, in their recent book, The Antihistamines, Feinberg, Malkiel, and Feinberg write as follows : “The sedative effect of the antihistamines is their most charactcristic side action. Dependin g on the individual susc*eptibilities of the person, the nature of the specific drug and dose, this sedative action may assume varying degrees of severity. . . . In more severe effects the patient becomes groggy and, if still more severe, very sleepy. The sedative effect often reaches a stage comparable to that obtained from a soporific dose of a barbiturate and not infrequently the effect is even more pronounced. . . . This sedative action, except in its mildest form, is objectionable and endangers the patient as well as those who are dependent, for their safety on his alert,ness” (p. 193) .6 With respect t,o thonzylamine (Neohetramine) these authors state : “The commonest side action is sedation. With doses of 50 mg. we obtained an incidence of side actions of 9 per cent, with 100 mg., 16 per cent. ,4rbesmanl noted an incidence of 16 per cent, while Criep and Aaron” reported 10 per cent, and the Friedlaenders’ gave an incidence of 12 per cent for doses of 50 to 100 mg. ” (p. 201) .6 The only report that we have found of an objective attempt to measure side effects of antihistamines is that of Holtkamp, Hagerman, and Whitehead,s who t,ested the effect of Benadryl, Pyribenzamine, and Hydryllin on ten students. As measures they employed a cancellation test, reaction time, two-point discrimination, blood pressure, pulse, and respiration. They also made a note of any subjective change that occurred. They found that there was no consistent effect produced on any test by any of the three agents. (Application of the chisquare test of statistical significance to their data indicates that no statistically significant differences were found.) However, they conclude their report as follows : “Care should be taken . . to warn the patient of the dangers in-