In a 6-month, double-blind multicenter trial conducted over the winter, the effects of daily administration of ambroxol retard (75 mg) were compared with those of placebo in preventing exacerbations and improving symptoms and clinical signs in chronic bronchitis patients. The trial was completed by 110 patients in the ambroxol group and by 104 in the placebo group. Initially, there were no significant differences between the groups. By the end of the 2nd month of treatment, 67.2% of the ambroxol group had had no exacerbations compared to 50.4% in the placebo group. At the end of the 6-month trial, 45.5% of the treatment group had had no exacerbations, compared to only 14.4% of the control group. These differences were statistically significant. Patients in the treatment group lost significantly fewer days through illness (442) and had fewer days when they needed antibiotic therapy (371) compared to the placebo group patients (837 and 781). Ambroxol also produced statistically significant symptomatic improvement, measured as difficulty in expectoration, coughing, presence of dyspnea and the auscultatory signs as compared to controls. Since ambroxol was well tolerated and compliance was good, it appears like a drug of choice for pharmacological prophylaxis of chronic bronchitis.

The single dose pharmacokinetics of flutoprazepam and its active N-desalkyl metabolite were determined in 8 normal subjects by using newly developed, highly sensitive, GC-MS and HPLC techniques. Following a 2 mg dose of the drug, the concentrations of unchanged flutoprazepam in serum were extremely low (below 5 ng/ml at 2 h) and declined rapidly to undetectable levels within 6-9 h after dosing. At all sampling times, the serum concentration of the N-dealkylated metabolite (N-desalkylflurazepam) was much greater than that of the parent compound. This metabolite appeared in serum rapidly (within 2 h), reached a peak between 2 and 12 h and declined slowly, with an elimination half-life of about 90 h on average. The serum concentration of two additional putative metabolites (3-hydroxy-flutoprazepam and N-desalkyl-3-hydroxy-flutoprazepam) was below the limit of detection (2 ng/ml) in all samples. Mild CNS effects (documented by prolonged choice reaction time) were present at 2 and 4 h but were no longer detectable at 9 h. It is suggested that unchanged flutoprazepam is unlikely to contribute significantly to clinical effects and that the drug exerts its therapeutic activity through conversion to the slowly eliminated N-desalkyl metabolite.

In a double-blind multicenter study versus placebo, the therapeutic effects of ambroxol (10 mg/kg, i.v. twice daily for 7 days) were studied in an appropriately selected population with severe respiratory failure. Treatment was given to 28 neonates with birth weight ≤ 2,000 g, appropriate for gestational age with idiopathic respiratory distress of such severity as to require assisted ventilation (IMV or IPPV) within 12 h of birth. The preliminary results showed that ambroxol treatment, and not placebo, increased survival, reduced the time during which mechanical ventilation was required and improved the FiO₂/PaO₂ ratio and the biochemical indices of pulmonary maturity. This latter improvement suggests that the amelioration of the IRDS clinical picture and the reduction of ventilatory requirement might be due to an increase in pulmonary surfactant. No side effects attributable to ambroxol therapy were observed in the treated infants.

No abstract