Comment: effects and side effects of H1- and H2-receptor antagonists in clinical situations.

The combined administration of H1- and H2-receptor antagonists has been shown to be beneficial in clinical situations in which the release of histamine causes trouble. It needs to be shown whether the use of either type of histamine antagonists would be as effective as the combination. Side effects of H1- and H2-receptor antagonists are mild and can be controlled. The various reports during this symposium have shown that most of the drugs which can release histamine have been replaced by other drugs not having this property. That seems to be more effective to cope with histamine than to try to antagonize the effects of endogenously released histamine. Let us call it the zero-option.