Epidural Calcitonin: Does it Provide Better Postoperative Analgesia? An Analysis of the Haemodynamic, Endocrine, and Nociceptive Responses of Salmon Calcitonin and Opioids in Epidural Anesthesia for Hip Arthroplasty Surgery

Abstract

Calcitonin is an endogenous regulator of calcium homeostasis, which acts principally on bone. At present, the principal indications for the therapeutic use of calcitonin are disorders involving hypercalcemia Paget's disease, acute pancreatitis, high-bone-turnover osteoporosis, pain associated with osteoporosis or bone metastases, and Sudeck's atrophy. The aim of this study was to compare the analgesic effects on postoperative pain of salmon calcitonin versus opioids administered epidurally. Our prospective study included 53 ASA I-II patients who were scheduled for total hip arthoplasty under epidural anaesthesia and who did not fulfill 1 or more of the exclusion criteria: a history of pituitary gland dysfunction; diabetes mellitus; obesity; contraindications to performing an epidural block and/or an allergy to calcitonin. These patients were randomly allocated into 3 groups (A, B, and C), each of which received postoperatively a different analgesic epidural mixture of 10 mL to control postoperative pain. Group A was given bupivacaine 0.5% (5 mL) + fentanyl 100 (2 mL) + NaCl 0.9% (3 mL). Group B was given bupivacaine 0.5% (5 mL) + salmon calcitonin 100IU (1 mL) + NaCl 0.9% (4 mL). Group C was given salmon calcitonin 100IU (1 mL) + NaCl 0.9% (9 mL). Perioperatively, 4 blood samples were taken from each patient at the following specific times: 1. Before the induction of anesthesia; 2. At the end of the operation and before the epidural administration of the analgesic mixture; 3. At the end of the first postoperative hour (1 hour after the administration of the analgesic mixture); and 4. At the end of the second postoperative hour (2 hours after the administration of the mixture). In each blood sample, glucose, cortisol, growth hormone, and prolactin plasma levels were determined in order to investigate the changes of these parameters as a result of the endocrine reaction to stress, and to pain relief. The analgesic solution was administered immediately after the second blood sample was taken. At the same time as the 4 blood samples were taken, haemodynamic parameters and pain scores were recorded. Epidural salmon calcitonin in combination with local anaesthetic produces an analgesic effect similar to fentanyl and with stable hemodynamic results. It also eliminates postoperative hyperglycaemia. The cortisol plasma level does not increase during the first postoperative hour, but increases significantly during the second postoperative hour. Growth hormone and prolactin plasma levels were stable in all patients in all 3 groups. This study shows that calcitonin is a suitable alternative for the treatment of acute postoperative pain.