Propranolol kinetics in hyperthyroidism [proceedings]

Abstract

The mean increase over baseline for the young subjects was 2.0 pmol/106 cells at a concentration of 10-8 M isoprenaline and rose to a maximum (11.3 pmol/106 cells) at 10-1 M isoprenaline. In the elderly subjects the mean concentration of cAMP at 10-1 M isoprenaline showed no increase over baseline while a maximum (5.4 pmol/106 cells) was observed at 10-4 M isoprenaline. The increase in cAMP in both young and old was a linear function of the log concentration of isoprenaline between 10-I M and 10-6 M isoprenaline. Covariance analysis of these linear portions showed no significant difference in slopes, but there was a significant difference in elevation (P < 0.01) with the line for the elderly displaced to the right.These findings support the suggestion that altered receptor function plays a role in the changed responsiveness to drugs observed in the elderly. In particular, they are consistent with the observation of Shand, Vestal & Woods (1978) of a decreased cardiac responsiveness to isoprenaline in the elderly.

The kinetics of propranolol in hypothyroidism [proceedings]

“…The rate of elimination of some drugs is altered by thyroid dysfunction (Eichelbaum, 1976). It has recently been shown that the clearance of propranolol is significantly increased in patients when hyperthyroid (Riddell, Neill, Kelly & McDevitt, 1979) but the influence of hypothyroidism on propranolol disposition is unknown. In a previous study the rate of elimination of oral propranolol was not found to differ significantly between a group of patients with hyperthyroidism and another group with hypo-oid, but there was no significant difference between the half-lives of intravenous propranolol in the two thyroid states.…”