SOME ACTIONS OF CHLORPROMAZINE

Since the first account of the pharmacology of chlorpromazine by Courvoisier, Fournel, Ducrot, Kolsky, and Koetschet (1953), much work has been done in an attempt to elucidate the mode of action of this drug. Investigations have been made by Bradley and Hance (1955), Dasgupta and Werner (1954), Hiebel, Bonvallet, and Dell (1954), Holzbauer and Vogt (1954), Longo, Von Berger, and Bovet (1954), Cathala and Pocidalo (1952), Huidobro (1954), Kopera and Armitage (1954), Melville (1954), Cosnier and Drouin (1954), Salzman, Moran, and Brodie (1955), and others. Chlorpromazine, like promethazine, is a phenothiazine derivative and possesses some of its actions to a greater degree, but it has negligible antihistamine properties. Perhaps the most outstanding property of chlorpromazine is its central depressant action, which is different from that of barbiturates, and is more marked than with other related phenothiazines. Its main peripheral action is an antagonism to adrenaline, and Kopera and Armitage (1954) showed that chlorpromazine also caused a paralysis of striated muscle. These authors compared the properties of chlorpromazine, promethazine, and pethidine, and found that all three substances showed the same types of pharmacological action, but chlorpromazine was the most active except in its anti-acetylcholine and antihistamine actions. In the present investigation we have determined pA2 values for the anti-acetylcholine and antihistamine properties of chlorpromazine. Its actions on striated muscle, on the heart for a quinidine-like effect, on body temperature, on insulin hypoglycaemia, and on liver glycogen, were also studied.