Beta-adrenoceptor blockade in stress due to oral surgery.

1 The effects of a single oral dose of 5 mg pindolol (P) and 100 mg metoprolol (M) were assessed in a double-blind study in 30 patients undergoing oral surgery. 2 Systolic and diastolic blood pressures and heart rate were reduced 90 min after oral medication and did not exceed initial values at rest during the procedure. 3 Noradrenaline, adrenaline and c-AMP concentrations did not differ at any time from the control values at rest after P, but were increased after local anaesthesia and during oral surgery after M as were the metabolic responses reflected by plasma concentrations of glucose and free-fatty acids. 4 Plasma levels of ACTH and cortisol showed the typical increase during the procedure, being independent of beta-adrenoceptor blockade. In contrast to the cardioselective antagonist M, prophylactic administration of the non-selective drug P prevented the sympathetic and metabolic responses to the stress of oral surgery. 5 Hypothalamic and adrenal stimulation were not reduced by either selective or non-selective beta-adrenoceptor blockade.