Correlation between propranolol in plasma and urine, renin-aldosterone system and blood pressure in essential hypertension

The influence of H2-receptor antagonists on steady-state concentrations of propranolol and 4-hydroxypropranolol

Twelve healthy male volunteers were treated with 1200 mg/day cimetidine, 300 mg/day ranitidine, or no H2-receptor antagonist (control) for seven days in a sequence determined by Latin-square design. Each treatment period was separated by a seven-day washout. On the third day of each treatment period, 80 mg propranolol every 12 hours for nine doses was initiated. Whole blood concentrations of propranolol and 4-hydroxypropranolol were measured at 12 time points during the 12-hour period following administration of the last propranolol dose. Heart rate was measured before each blood sample was withdrawn. Cimetidine treatment was associated with a 47 per cent increase in the area under the propranolol concentration-time curve and a 17 per cent increase in elimination half-life of propranolol. Ranitidine had no significant effect on the concentration-time profile of propranolol. There were no significant differences in the 4-hydroxypropranolol pharmacokinetic parameters during any of the treatments. There was, however, a significant decrease in the average 4-hydroxypropranolol-to-propranolol steady-state concentration ratio during the cimetidine treatment. There was no significant difference in heart rate between any of the treatments. The elevation of propranolol concentrations during cimetidine treatment is likely due to metabolic inhibition by cimetidine.

Changes in blood chemistry in hypertensive patients during propranolol therapy

Propranolol induced changes in blood plasma chemistry were followed in thirty hypertensive patients (WHO I-II) who were seen each week during 14-15 weeks. The initial 4 weeks were a drug free period and the next 2 weeks were a drug adjustment period. After that the patients were on an unchanged propranolol dose for 8 weeks (40, 80 or 160 mg four times daily). For all observed changes the correlation was studied to (1) dose, (2) free and total simultaneously determined plasma concentration and (3) free and total average plasma concentration of unchanged drug during the preceding 24 h period. Total protein and albumin did not change significantly. After 4 and 8 weeks on the final dose orosomucoid was increased significantly (by 10%) compared with the value from the end of the drug free period. Creatinine rose significantly during the initial 4-6 weeks therapy to remain at the same level during the last 4 weeks. Urate was increased at the two lowest dose levels. Total cholesterol fell significantly (5%) while triglycerides increased significantly (16%). T4 rose significantly, T3 fell and r-T3 rose significantly in a dose dependent way. Interindividually r-T3 was the only biochemical change showing a significant relationship to the propranolol plasma concentration. The relationship reached the highest level of significance to the average 24 h free concentration.