Comparative pharmacodynamics and pharmacokinetics of conventional and long-acting propranolol.

This investigation was conducted to compare the pharmacokinetic and pharmacodynamic effects of single and multiple doses of conventional propranolol and long-acting propranolol in healthy human volunteers. Two double-blind, randomized, double-crossover, Latin square studies were carried out. One study evaluated long-acting propranolol 160 mg/d, conventional propranolol 40 mg qid, or placebo for seven days in 24 men. The other study compared long-acting propranolol 80 mg/d, conventional propranolol 20 mg qid, or placebo for seven days in 27 men. At specific times after the administration, blood samples were obtained, and heart rate and blood pressure were measured; exercise tests were done both on the first day and at steady state (day 7). In both studies, the area under the plasma propranolol concentration-time curve and the peak concentration were significantly less (P less than .0001) after the administration of long-acting propranolol compared with conventional propranolol on both day 1 and day 7; in addition, the elimination half-life was longer after administration of the long-acting preparation (9 hr) compared with that following the conventional dosage form (4 hr). Both conventional and long-acting propranolol significantly decreased the exercise heart rate at each of the selected time points (P less than .05) compared with placebo. Reduction in exercise heart rate was greater with conventional propranolol than with the long-acting formulation, but the differences were not statistically significant, when exercise was performed only at trough levels of the conventional drug. The decreases in exercise heart rate were correlated with plasma propranolol concentrations.

Etodolac, aspirin, and gastrointestinal microbleeding.

The effects of etodolac, a new nonsteroidal anti-inflammatory drug, on gastrointestinal (GI) microbleeding were quantitatively assessed in two studies in healthy adult men. The first was a two-group, open-label, parallel comparison of etodolac, 600 mg/day, aspirin, 2600 mg/day, and placebo in 20 subjects; the second was a four-group, double-blind, parallel comparison of etodolac, 600, 800, and 1200 mg/day, aspirin, 2600 mg/day, and placebo in 41 subjects. Subjects in both studies received a single-blind placebo on days 1 through 7, either etodolac or aspirin on days 8 through 14, and a single-blind placebo on days 15 through 19. GI blood loss (milliliters per day) was estimated by the radiolabeled (51Cr) erythrocyte method and was based on daily radioactivity counts of stool specimens and regression-estimated daily blood radioactivity. Etodolac, 600 mg/day, induced no significant GI blood loss at any time during the experiments, nor was there significant blood loss after 800 and 1200 mg/day in experiment 2. Blood loss was noted after aspirin in both.