EFFECTS OF CLONIDINE ON THE PITUITARY HORMONAL RESPONSE TO PELVIC-SURGERY

We have investigated the effects of the central alpha(2) adrenorecepto r agonist, clonidine, given i.v. before induction of anaesthesia, on t he haemodynamic and endocrine responses to pelvic surgery. Twenty pati ents were allocated randomly to receive either clonidine 3 mu g kg(-1) or an equivalent volume of 0.9% sodium chloride solution. Arterial pr essure, heart rate, and circulating concentrations of cortisol, growth hormone, glucose and lactate were measured during and in the 24 h aft er total abdominal hysterectomy. Arterial pressure and heart rate decr eased significantly in the clonidine group during surgery and in the e arly postoperative period. There were no differences between groups in serum cortisol or growth hormone concentrations throughout the study. Despite an effective decrease in the cardiovascular response to surge ry, clonidine 3 mu g kg(-1) i.v. had no significant effect on pituitar y hormone secretion.