Patient/caregiver was instructed upon calcitriol and mechanism of action as follows:
- Low levels of serum calcium in the body stimulate increased synthesis of parathyroid hormone by the parathyroid glands.
- Parathyroid hormone and low levels of serum calcium and phosphorus in the body also stimulate synthesis of calcitriol by the kidneys.
- Calcitriol is the final natural active form of vitamin D, which is synthesized from precursors/prior forms synthesized in the skin and liver. This precursor form synthesized in the liver is converted in the kidneys to calcitriol. Calcitriol, in association with parathyroid hormone, by various mechanisms, plays a significant role in regulating the serum concentrations of calcium and phosphorus.
- Increased calcitriol secretion, together with increased parathyroid hormone, results in increased resorption of bone and consequently, leads to mobilization of calcium and phosphorus from the bone into the blood, thus helping to offset the low levels of these salts in the serum.
- Also, they help with increased intestinal absorption of calcium and phosphorus from the food sources. They also help with reabsorption of calcium in the kidneys, thus helping to restore optimal concentrations of serum calcium and phosphorus.
- Once optimal concentrations of serum calcium and phosphorus are reached, calcitriol helps with mobilization and deposition of calcium and phosphorus in the bones, thus helping with the mineralization and strengthening of the bones. After the optimal concentrations of serum calcium and phosphorus are reached, calcitriol also helps with inhibiting the secretion of parathyroid hormone, as continued secretion of parathyroid hormone can lead to further bone resorption, weakening, and can result in osteoporosis.
- In individuals with compromised kidney and parathyroid gland function and other disorders contributing to low calcitriol synthesis in the body, it can be given as a supplement.
