Plasma drug concentrations, and heart rate and blood pressure responses to exercise at a predetermined load were examined in twelve hypertensive patients following single and repeated doses of oxprenolol administered once daily as oral osmotic drug delivery systems (10/170 and 16/260 oxprenolol OROS). 2. Plasma oxprenolol concentration profiles after each preparation were consistent with the criteria for sustained drug release. Levels immediately after exercise were significantly higher than those prior to exercise (P less than 0.001), but differences were slight. 3. Both OROS drug forms reduced exercise heart rate for 24 h after single and repeated doses; effects were greater for 16/260 OROS than for 10/170 OROS. Significant reductions in post-exercise systolic BP were observed 24 h after drug administration and after repeated doses there was little difference between the preparations. Effects on diastolic BP after exercise were slight. 4. The relationship between plasma oxprenolol concentrations and exercise heart rates fitted an exponential mathematical model which makes allowance for inter-individual variability. No such kinetic-dynamic relationship could be defined for post-exercise systolic or diastolic BP.
