Assessment of antitussive effects by citric acid threshold

Abstract

The cough threshold to citric acid inhalation was measured in eight subjects by single inhalations of increasing concentrations of citric acid until a cough was consistently produced. The cough threshold was measured before and after 60 mg glaucine, 60 mg codeine and matched placebo on three separate days a week apart. Base-line cough threshold in each subject was consistent from week to week. Codeine increased the threshold by more than one citric acid concentration in three subjects. Placebo and glaucine did not produce a threshold change of more than one citric acid concentration. We conclude that the citric acid threshold is a simple measure of antitussive activity. No such activity was found with glaucine.

Peripheral Mechanisms II: The Pharmacology of Peripherally Active Antitussive Drugs

“…Dextromethorphan (Grattan et al 1995;Karttunen et al 1987) (Braman 2006) × ( ± (Danzon et al 1988;Lilienfield et al 1976) ± (Dicpinigaitis and Gayle 2003b) Primarily used as an antiallergic drug (Ventresca et al 1990) (Foresi et al 1996;Stone et al 1993b;Ventresca et al 1990) Glaucine × (Rees and Clark 1983) (Ruhle et al 1984) (Gastpar et al 1984) Local anaesthetics (Choudry et al 1990;Hansson et al 1994) (Sheppard et al 1983) (Midgren et al 1992) (Chong et al 2005;Fuller and Jackson 1990;Trochtenberg 1994) β 2 −agonists × (Smith et al 1991) (Higenbottam 1987;Lowry et al 1987) ...…”