The clinical pharmacology of salmefamol.

1 The absorption, excretion and metabolism of [(3)H]-salmefamol, a new sympathomimetic bronchodilator drug, have been studied in asthmatic patients. 2 Following oral administration of 1 or 2 mg to four patients the drug was well absorbed, peak plasma levels occurring from 0.6-2.0 h after administration. An improvement in forced expiratory volume in 1 s (FEV(1)) (ranging from 12-50% above baseline) was seen. 3 Following aerosol administration of 0.22-0.34 mg to four patients a rapid rise in FEV(1) was seen (range 26-117%). The plasma and urinary pictures following this route were similar to those seen after oral administration, suggesting that the majority of the dose was swallowed. 4 Very little free salmefamol was found in plasma or urine, the majority being present as metabolites. Urinary radioactivity was mainly present in the form of sulphate conjugates of at least two compounds, one of which was salmefamol. The other compound has not been identified but it is suggested that it may be an active metabolite.