ISSN:
1420-908X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract In a controlled clinical trial on histamine release in anaesthesia, it was suspected that the antihypertensive fixed-dose combination drugBetathiazid ® masked clinical signs of histamine release. By structure analysis of its constituents (propranolol, triamterene and hydrochlorothiazide), hydrochlorothiazide was considered to be most likely an H1-antagonist. An aqueous solution of the whole drug tablet (2×10−4 M propranolol, 2.9×10−5 M triamterene, 1.7×10−5 M hydrochlorothiazide) and of the individual substances (1 μM each) was tested in the classical H1-receptor assay using the guinea pig ileum. Betathiazid® in total suppressed the contraction to histamine (78% inhibition), but not to carbachol. Propranolol and triamterene had depressive effects (14% and 38% inhibition), but hydrochlorothiazide potentiated the contractions to histamine (75% potentiation). In all cases, the type of antagonism was not competitive. Although different mechanisms may account for the modulatory effects of Betathiazid®, they have to be considered in the interpretation of clinical studies, especially for relating mediator concentrations with clinical signs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02007798
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