Bronchodilator and antiallergic effects of thiazinamium chloride in guinea pigs, rats, cats and dogs.

This study characterized the in vivo pulmonary pharmacology of thiazinamium chloride administered largely by the aerosol route in different animal species. The compound has greater anticholinergic but weaker antihistaminic activity than promethazine, the parent compound. It was less potent than atropine or ipratropium as an anticholinergic and had a shorter duration of action, but unlike these compounds it had long-lasting antihistaminic activity. It is effective in both IgG- and IgE-induced models of passive lung anaphylaxis in guinea pigs and rats, respectively. In Ascaris-induced allergic asthma in the conscious dog it produced a dose-related inhibition of the antigen-induced bronchospasm. No major side effects were observed in acute oral and inhalation toxicity studies in guinea pigs or rhesus monkeys. The results demonstrate that thiazinamium chloride is a safe, potent and efficacious bronchodilator after aerosol administration, with a rapid onset and moderate duration of action in animal models.