Changes in the Patency of the Dog's Eustachian Tube Induced by Histamine and Antihistamines

A simple technique designed to measure the change in eustachian tube patency (ETP) was used to test the effect of graded doses of histamine on the eustachian tube and the effectiveness of antihistamine blockade of histamine. Four antihistamines were used—carbinoxamine maleate (Clistin), promethazine hydrochloride (Phenergan), pyrilamine maleate (Pyrilamine), and chlorpheniramine maleate (Chlor-Trimeton). In general, there was a close correlation between the clinical dose of antihistamine and the histamine blocking dose in the experimental animals.