From the FDA Drug Label
The development of hypocalcemia has not been reported in studies in healthy volunteers or postmenopausal women. In normal adults, who have a relatively low rate of bone resorption, the administration of exogenous calcitonin results in only a slight decrease in serum calcium in the limits of the normal range. However, the pharmacologic actions of FORTICAL® calcitonin-salmon (rDNA origin) Nasal Spray suggest that this could occur in overdose
Calcitonin does not typically cause hypocalcemia in the usual dosage range, as it only results in a slight decrease in serum calcium within the normal range 1, 1. However, hypocalcemia could potentially occur in overdose situations 1.
From the Research
Yes, calcitonin causes hypocalcemia, as it inhibits osteoclast activity, reduces bone resorption, and increases calcium excretion by the kidneys, ultimately leading to decreased serum calcium levels. Calcitonin is a hormone produced by the parafollicular C cells of the thyroid gland that acts to lower blood calcium levels 2. It works through several mechanisms: it inhibits osteoclast activity in bones, reducing bone resorption and calcium release into the bloodstream; it increases calcium excretion by the kidneys; and it decreases calcium absorption in the intestines. These combined actions result in decreased serum calcium levels. Physiologically, calcitonin serves as a counterbalance to parathyroid hormone (PTH), which increases blood calcium.
Some key points to consider when using calcitonin therapeutically include:
- Monitoring patients for hypocalcemia, especially if they have pre-existing low calcium levels or vitamin D deficiency
- Typical doses of 100-200 IU daily via injection or nasal spray for conditions like Paget's disease, hypercalcemia, and osteoporosis
- The potential for calcitonin to inhibit osteoblast activity and bone turnover, as demonstrated in genetically modified mice 2
- The importance of understanding the relationship between the pharmacological effects and the physiological roles of calcitonin and other peptides in the calcitonin family
It is essential to prioritize the most recent and highest quality study, which in this case is 2, published in 2019 in the journal Physiological Reviews. This study provides a comprehensive review of the activity of peptides of the calcitonin family in bone, including the physiological role of calcitonin and its effects on osteoclasts and osteoblasts.