Calcitonin nasal spray reduces opioid withdrawal syndrome without modification of endogenous opioid secretion

It has been suggested that the well known analgesic effect of calcitonin (CT) may result from an enhanced secretion of opioid peptides. The purpose of this double-blind, controlled study was therefore to evaluate the effectiveness of CT on the opiate withdrawal syndrome. 20 drug addicts were randomly allocated to receive either 200 UI/day of salmon CT (n = 10) or placebo (n = 10) by nasal spray, after the abrupt withdrawal of low-dose methadone (20 mg/day). The severity of the withdrawal syndrome was evaluated by means of a score derived from a symptom check-list. Plasma beta-endorphin, glucose and insulin levels were measured before and after CT administration. The subjects treated with spray CT had significantly lower score than those treated with placebo. Beta-endorphin levels did not show any significant variation in both groups. An inhibitory action of CT on insulin secretion was observed. Our data suggested that CT might be considered a useful supportive measure for opiate withdrawal. CT action does not seem to involve the opioid system, but is probably mediated by a direct action on specific receptors or by a modulation of noradrenergic pathways.