1. Prenalterol is rapidly and completely absorbed after oral administration with peak concentrations reached after 30 minutes. 2. Prenalterol is rapidly distributed to extravascular tissues after intravenous administration. 3. The extent of bioavailability after administration of prenalterol as a solution is about 25% of an intravenous dose. After administration of 20 mg prenalterol in a controlled release preparation the bioavailability is increased to about 45%. 4. The half-life of the elimination phase is close to 2 hours. 5. 60% of an intravenous dose and 15% of an oral dose is eliminated unchanged by renal excretion. The rest is mainly excreted as the sulphate ester of prenalterol.