Antihypertensive activity at rest and during dynamic exercise of oxprenolol oros 16/260 24 hours after dosing: A double-blind comparison with atenolol

Oxprenolol oros 16/260 (osmotic delivery system) and atenolol 100 mg were compared in their antihypertensive activity at rest and during dynamic exercise. Twenty out-patients with arterial hypertension received for 4 weeks oxprenolol oros 16/260 and atenolol 100 mg once-daily in random order and double-blind. All measurements were made 24 to 25 hours after intake. There was no difference between the two treatments in their antihypertensive activity at rest. Results of a symptom-limited cycloergometric exercise test showed no differences between the two treatments in exercise duration or peak blood pressure. No noticeable adverse effect was noted. At rest, the heart rate decreased 9-11 beats per minute after oxprenolol oros 16/260 and 18-20 beats per minute after atenolol in respect to placebo washout (P<0.05 in the comparison between the two β-blockers). The step-by-step rise in heart rate with exercising was parallel with the two β-blockers although more down-located after atenolol (mean values: 94.1 → 106.5 → 114.6 → 134.4 b.p.m. after oxprenolol oros; 87.8 → 99.1 → 107.4 → 123.8 b.p.m. after atenolol). The difference in exercise heart rate between the two β-blockers was significant at all steps (all P<0.05). In conclusion, oxprenolol oros 16/260 and atenolol 100 mg were not dissimilar in their antihypertensive activity 24 to 25 hours after dosing after a 4-week treatment period. At rest and during dynamic exercise the heart rate was reduced slightly less by oxprenolol oros than by atenolol, possibly as a result of partial agonist activity of the former, but this difference did not appear to influence antihypertensive activity or tolerability.