STUDY IN MICE OF BENZODIAZEPINE-ANTICHOLINERGIC INTERACTION - PROTECTION AGAINST RESTRAINT-IMMERSION AND FORCED EXERTION-INDUCED GASTRIC MUCOSAL EROSION

The effectiveness of benzodiazepines and anticholinergics administered alone or in combination in preventing restraint-immersion and forced exertion-induced gastric mucosal erosion was investigated in mice. The benzodiazepines used were diazepam and chlordiazepoxide HCl and the anticholinergics were propantheline bromide and clidinium bromide. The administration of a benzodiazepine with an anticholinergic resulted in additive or supra-additive protective effects in both systems. In the restraint-immersion system, diazepam combined with propantheline bromide at a ratio of 1 to 13.7 yielded a 4.53-fold supra-additive effect. At ratios of 4.6 or 1.5 parts of propantheline bromide to 1 part of diazepam an additive effect was observed. One part of diazepam, when combined with 1.4 to 12.0 parts of clidinium bromide resulted in supra-additive effects of about 1.5-fold. The co-administration of chlordiazepoxide HCl and clidinium bromide in ratios of 2 to 1 or 2.5 to 1 resulted in supra-additive effects of 2.4- and 1.85-fold, respectively. At higher and lower ratios additive effects were demonstrated. In the forced exertion system, diazepam combined with either anticholinergic resulted in supra-additive effects of 2- to 3-fold which occurred at ratios of diazepam to the anticholinergic varying over an 8-fold range. The co-administration of 2 parts of chlordiazepoxide HCl and 1 part of clidinium bromide resulted in a 2.84-fold supra-additive effect in the forced exertion system. These results are discussed in relation to the use of benzodiazepine anticholinergic combinations in the treatment of human gastric and duodenal ulcer disease.