Propofol-containing sedatives increase levels of parathyroid hormone

Objective: To evaluate the effects of propofol and propofol containing diso dium edetate (ethylenediaminetetraacetic acid [EDTA]) on the parathyroid-ca lcium axis in normal subjects. Design: Randomised, double-blind, age-stratified, crossover trial. Setting: Single centre. Patients: A total of 50 healthy subjects. Interventions: Each subject was randomised to receive propofol or propofol containing EDTA on day 1 and the alternate treatment between days 15 and 29 , with a 2-week washout period in between. On the day of treatment, subject s received a bolus of trial medication (1 or 2 mg/kg) followed by a 60-minu te observation period. At the end of 60 minutes, subjects received trial me dication infused for 60 minutes at 1 of 4 randomised infusion rates (25, 50 , 100, or 200 mug/kg per min). Subjects were monitored for an additional 60 minutes following the infusion. Measurements and Results: Blood pressure, heart rate, respiratory rate, oxy gen saturation, blood ionised calcium concentration, serum total magnesium concentration, serum intact parathyroid hormone (PTH) level, and plasma EDT A level were assessed at periodic intervals during and following the bolus and continuous infusion of trial medication. Mean arterial pressure signifi cantly decreased (p < 0.05) following the bolus injection of both trial med ications and returned to baseline at 60 minutes; it significantly decreased again during the continuous infusion and returned to baseline during recov ery. Heart rate and respiratory rate fluctuated in both groups with signifi cant increases and decreases throughout the study period following the bolu s injection; both returned to baseline during the recovery period in each g roup. Ionised calcium and total magnesium concentrations remained within no rmal limits and were unchanged in response to both study medications. PTH l evels significantly increased following the bolus injection of both study d rugs. The increase in PTH levels was greater with higher doses of study med ication during the infusion period. There was no difference in the response of blood pressure, heart rate, respiratory rate, or PTH levels between pro pofol and propofol with EDTA. EDTA levels increased significantly during th e infusion of propofol with EDTA, reaching mean levels of 240 ng/mL. Conclusions: The results of this study indicate that propofol increases PTH levels in normal subjects; however, propofol with EDTA does not alter ioni sed calcium or total magnesium concentrations.