ATC Group: R06AD Phenothiazine derivatives

Alimemazine has a central sedative effect, comparable to that of chlorpromazine, but largely devoid of the latter’s antiadrenaline action. It has powerful antihistamine and anti-emetic actions. Alimemazine is used to treat neurosis, depression and anxiety of different origins. It prevents and relieves allergic conditions, which cause pruritus and urticaria by blocking histamine produced by the body during an allergic reaction. Alimemazine competes with free histamine for binding at HA-receptor sites. This antagonizes the effects of histamine on HA-receptors, leading to a reduction of the negative symptoms brought on by histamine HA-receptor binding.

Mequitazine is a phenothiazine derivative with the actions and uses of antihistamines. Antihistamines diminish or abolish the main actions of histamine in the body by competitive, reversible blaockade of histamine receptor site on tissues; they do not inactivate histamine or prevent its synthesis or release. Antihistamines are used for palliative treatment of allergic reactions.

Promethazine is a potent, long acting, antihistamine with additional anti-emetic central sedative and anti-cholinergic properties.