Calcitriol Uses

Calcitriol is a vitamin D analog that helps to increase calcium levels in the blood. This medication is used to treat low calcium levels and metabolic bone disease in people with severe chronic renal failure who are on chronic renal dialysis. It is also used to treat hypocalcemia (low calcium) in people with idiopathic hypoparathyroidism (low parathyroid levels), postsurgical hypoparathyroidism, and pseudohypoparathyroidism. Calcitriol is also prescribed for secondary hyperparathyroidism (high parathyroid hormone levels) and metabolic bone disease in people with moderate to severe chronic renal failure who are not yet on dialysis.

There may be other uses of calcitriol, such as to treat vitamin D-dependent rickets and osteomalacia (weak bones caused by vitamin D deficiency in children and adults, respectively) and familial hypophosphatemia (weak bones caused by a decreased ability to break down vitamin D). Other uses of calcitriol are to increase serum calcium levels in premature babies. Your pharmacist or doctor can give you further information on calcitriol uses and the associated benefits versus risks.

Calcitriol Mechanism of Action

Calcitriol works by increasing intestinal calcium absorption and lowering parathyroid hormone levels.

Calcitriol Doses

The dose of calcitriol is carefully chosen for each patient. Calcitriol comes in the form of capsules (0.25 mcg or 0.50 mcg) and an oral solution (1 mcg/mL). Typical doses of calcitriol are as follows:

Dialysis patients: The initial dose is 0.25 mcg/day. This may be increased by 0.25 mcg/day at 4- to 8-week intervals. Some patients with only slightly low serum calcium levels may need to take 0.25 mcg of calcitriol every other day. Most patients undergoing chronic renal dialysis require maintenance doses between 0.5 mcg and 1 mcg daily. In some patients, calcitriol helps to normalize serum calcium levels but does not suppress secondary hyperparathyroidism. 

Hypoparathyroidism: The initial dosage is 0.25 mcg/day. This may be increased by 0.25 mcg/day at 2- to 4-week intervals. Most adults and children (age 6 plus) respond to doses between 0.5 mcg and 2 mcg daily. Pediatric patients between 1 and 5 years old with hypoparathyroidism are usually given calcitriol at doses between 0.25 mcg and 0.75 mcg daily. Dosage recommendations for pediatric patients under 6 years of age with pseudohypoparathyroidism are not available.

Predialysis patients: The initial dosage is 0.25 mcg/day. This may be increased to 0.5 mcg/day if needed in adults and pediatric patients aged 3 years and older. For pediatric patients under 3 years of age, the recommended initial dosage is based on the child’s body weight.

When the dose of calcitriol is being adjusted, your doctor will check serum calcium levels at least twice weekly. Keep all your medical and lab appointments. Your doctor will need to discontinue calcitriol if the medicine is found to induce hypercalcemia (high serum calcium levels) until your calcium levels normalize. Your doctor may also ask you to decrease your dietary calcium intake if you have high blood calcium levels.