Effect of zatebradine, a novel 'sinus node inhibitor', on pulmonary function compared to placebo

Zatebradine, a member of a novel class of drugs called 'sinus node inhibitors', is a specific heart rate lowering drug suitable for the treatment of stable angina pectoris. Animal studies showed that relatively high intravenous doses of zatebradine contracted guinea-pig airways by a histamine-like mechanism. Therefore, the objective of the present study was to assess the bronchopulmonary effects in asthmatic patients who showed a moderate to severe bronchial hyperreactivity towards histamine (PC20 FEV1 < or = 1 mg/ml). Moreover, it had to be established to what extent the bronchial responsiveness to inhaled salbutamol was retained and whether pulmonary effects were related to the severity of bronchial hyperreactivity. By means of a double-blind cross-over design, single oral doses of zatebradine (10 mg) or placebo were administered on two occasions with a washout phase of at least 3 days. Sixteen patients, four female and 12 male, with stable mild to moderate bronchial asthma (FEV1 less than 80% predicted) were selected. Their mean age was 54 years and the mean FEV1 was 1.831 (59% predicted). They showed a mean improvement in FEV1 of 27% 15 min after inhaling 200 micrograms salbutamol; the mean PC20 was 0.35 mg/ml. Following test drug intake, the respiratory and cardiac effects were assessed at regular time intervals up to 6 h after administration. In comparison to placebo, zatebradine induced small, but significant (P < 0.05), mean falls of 128 ml and 168 ml in FEV1 at 3 h and 6 h after drug intake. A large inter-individual variation in response was noted.(ABSTRACT TRUNCATED AT 250 WORDS)