Introduction

Polypeptide hormone secreted by parafollicular cells (C cells) of thyroid gland; acts predominantly on bone to lower serum calcium concentration and inhibit bone resorption.

Uses for Calcitonin

Paget Disease of Bone

Treatment of Paget disease of bone. Consider treatment with calcitonin or a bisphosphonate (e.g., alendronate, etidronate, pamidronate, risedronate) in patients with biochemical markers suggestive of an increase in bone remodeling, those who are symptomatic, and those at risk for future complications from their disease (e.g., those with pagetic lesions in weight-bearing regions or adjacent to joints).

Hypercalcemia

Early treatment of hypercalcemic emergencies (with other appropriate agents) when a rapid decrease in serum calcium concentration is required.

Postmenopausal Osteoporosis

Treatment of postmenopausal osteoporosis in women >5 years postmenopause.

In addition to adequate intake of calcium/vitamin D and other lifestyle modifications (e.g., exercise, avoidance of excessive alcohol and tobacco use), experts recommend that pharmacologic therapy for osteoporosis be considered in postmenopausal women with high risk of fractures (generally those who have experienced a previous hip or vertebral fracture or who have low BMD); pharmacologic therapy also may be considered in postmenopausal women with low bone mass, although there is less evidence supporting overall fracture risk reduction in such patients.

Use of a drug with proven antifracture efficacy is recommended; experts generally recommend calcitonin as a last-line therapy when other drugs are not effective or tolerated.

Individualize choice of therapy based on potential benefits (with respect to fracture risk reduction) and adverse effects of therapy, patient preferences, comorbidities, and risk factors.

Glucocorticoid-induced Osteoporosis

Has been used in the treatment of glucocorticoid-induced osteoporosis^{† [off-label]}; however, other therapies (e.g., oral bisphosphonates) are preferred.

Calcitonin Dosage and Administration

General

Paget Disease of Bone

• Monitor by periodic determinations of serum alkaline phosphatase and urinary hydroxyproline excretion as well as evaluation of symptoms.

• Investigate possibility of antibody formation in any patient who shows initial response but subsequently relapses.

Postmenopausal Osteoporosis

• Monitor BMD.

Administration

Administer by sub-Q or IM injection (Paget disease of bone, hypercalcemia, postmenopausal osteoporosis) or intranasally (postmenopausal osteoporosis).

IM Administration

IM injection preferred when injection volume >2 mL.

Use multiple sites of injection when volume >2 mL.

Sub-Q Administration

Sub-Q injection preferred for patient self-administration.

Intranasal Administration

Administer once daily (as a single spray in 1 nostril) using metered-dose spray pump supplied by manufacturer. Alternate nostrils daily.

Allow solution to reach room temperature before priming pump and administering first dose.

Prime pump before first dose; do not prime before each dose.

Miacalcin: To prime pump, hold bottle upright and depress the 2 white side arms of pump toward the bottle until full spray is produced.

Fortical: To prime pump, hold bottle upright and depress the 2 white side arms of pump toward the bottle at least 5 times until full spray is produced.

Administer dose by placing nozzle in nostril with head in upright position and firmly depressing pump toward bottle.

Discard spray pump after 30 actuations, since the correct drug dose per actuation cannot be assured if used for additional doses.

Dosage

Activity of calcitonin salmon expressed in terms of International Units (units).

Intranasal spray pumps deliver 0.09 mL of solution per actuation; each 0.09-mL spray delivers 200-unit dose.

Adults

Paget Disease of Bone

Sub-Q or IM

Initial dosage: 100 units (0.5 mL) daily.

Maintenance: 50 units (0.25 mL) daily or every other day; higher dosage (100 units daily) appropriate in patients with serious deformity or neurologic involvement.

Dosage >100 units daily usually does not produce an improved response in patients who relapse while receiving calcitonin.

Hypercalcemia

Sub-Q or IM

Initially, 4 units/kg every 12 hours; may increase dosage after 1 or 2 days (if response not adequate) to 8 units/kg every 12 hours; may further increase dosage after 2 days (if response not adequate) to 8 units/kg every 6 hours.

Postmenopausal Osteoporosis

Sub-Q or IM

Minimum effective dosage not established; 100 units every other day may be effective in preserving vertebral BMD.

Intranasal

200 units (1 spray) daily.

Prescribing Limits

Adults

Hypercalcemia

Sub-Q or IM

Maximum 8 units/kg every 6 hours.

Contraindications

• Known hypersensitivity to calcitonin salmon.

Warnings/Precautions

Sensitivity Reactions

Serious allergic reactions (bronchospasm, swelling of tongue or throat, anaphylactic shock, at least 1 death due to anaphylaxis) reported in patients receiving calcitonin injection. Differentiate hypersensitivity reactions from generalized flushing and hypotension.

Allergic-type reactions also reported in patients receiving calcitonin nasal spray.

Appropriate agents for treatment of hypersensitivity reactions should be readily available.

For patients with suspected sensitivity to calcitonin, consider skin testing prior to initiating therapy.

General Precautions

Hypocalcemic Tetany

Possibility of hypocalcemic tetany following parenteral administration; have calcium injection readily available, particularly during first several doses of parenteral calcitonin.

Laboratory Monitoring

Coarse granular casts and casts containing renal tubular epithelial cells reported in some young adult volunteers at bedrest who received parenteral calcitonin in a study of its effect on immobilization osteoporosis. Cl_cr not altered and proteinuria not reported; urine sediment returned to normal within 4 days following drug discontinuance. Effect not reported by other investigators.

Periodic examinations of urine sediment are recommended in patients receiving long-term parenteral therapy.

Radiographic Monitoring

In patients with Paget disease, carefully evaluate radiographic evidence of marked progression of pagetic lesions to rule out osteogenic sarcoma (since frequency is increased in patients with Paget disease).

Nasal Examinations

Periodic nasal examinations with visualization of nasal mucosa, turbinates, septum, and mucosal blood vessel status are recommended for patients receiving calcitonin nasal spray.

Discontinue nasal spray if severe ulceration of nasal mucosa (i.e., ulcers >1.5 mm in diameter or penetrating below the mucosa, ulcers associated with heavy bleeding) occurs. For smaller ulcers, interrupt therapy until healing occurs.

Specific Populations

Pregnancy

Category C.

Lactation

Inhibits lactation in animals. Not known whether calcitonin is distributed into human milk. Use not recommended.

Pediatric Use

Experience with calcitonin in children with juvenile Paget disease is very limited; the relationship between this disorder and adult Paget disease is not established.

Experience with calcitonin in children with idiopathic juvenile osteoporosis is very limited; the relationship between this disorder and postmenopausal osteoporosis is not established.

Data are inadequate to support use of calcitonin in children.

Geriatric Use

Adverse nasal effects (i.e., rhinitis, irritation, congestion) reported more frequently in patients >65 years of age receiving calcitonin nasal spray. Nasal effects described as mild.

Common Adverse Effects

With parenteral therapy, nausea, vomiting, injection site reaction, flushing of the face, ears, hands, and feet.

With intranasal therapy, rhinitis, nasal symptoms, back pain.

General

Paget Disease of Bone

• Monitor by periodic determinations of serum alkaline phosphatase and urinary hydroxyproline excretion as well as evaluation of symptoms.

• Investigate possibility of antibody formation in any patient who shows initial response but subsequently relapses.

Postmenopausal Osteoporosis

• Monitor BMD.

Administration

Administer by sub-Q or IM injection (Paget disease of bone, hypercalcemia, postmenopausal osteoporosis) or intranasally (postmenopausal osteoporosis).

IM Administration

IM injection preferred when injection volume >2 mL.

Use multiple sites of injection when volume >2 mL.

Sub-Q Administration

Sub-Q injection preferred for patient self-administration.

Intranasal Administration

Administer once daily (as a single spray in 1 nostril) using metered-dose spray pump supplied by manufacturer. Alternate nostrils daily.

Allow solution to reach room temperature before priming pump and administering first dose.

Prime pump before first dose; do not prime before each dose.

Miacalcin: To prime pump, hold bottle upright and depress the 2 white side arms of pump toward the bottle until full spray is produced.

Fortical: To prime pump, hold bottle upright and depress the 2 white side arms of pump toward the bottle at least 5 times until full spray is produced.

Administer dose by placing nozzle in nostril with head in upright position and firmly depressing pump toward bottle.

Discard spray pump after 30 actuations, since the correct drug dose per actuation cannot be assured if used for additional doses.

Dosage

Activity of calcitonin salmon expressed in terms of International Units (units).

Intranasal spray pumps deliver 0.09 mL of solution per actuation; each 0.09-mL spray delivers 200-unit dose.

Adults

Paget Disease of Bone

Sub-Q or IM

Initial dosage: 100 units (0.5 mL) daily.

Maintenance: 50 units (0.25 mL) daily or every other day; higher dosage (100 units daily) appropriate in patients with serious deformity or neurologic involvement.

Dosage >100 units daily usually does not produce an improved response in patients who relapse while receiving calcitonin.

Hypercalcemia

Sub-Q or IM

Initially, 4 units/kg every 12 hours; may increase dosage after 1 or 2 days (if response not adequate) to 8 units/kg every 12 hours; may further increase dosage after 2 days (if response not adequate) to 8 units/kg every 6 hours.

Postmenopausal Osteoporosis

Sub-Q or IM

Minimum effective dosage not established; 100 units every other day may be effective in preserving vertebral BMD.

Intranasal

200 units (1 spray) daily.

Prescribing Limits

Adults

Hypercalcemia

Sub-Q or IM

Maximum 8 units/kg every 6 hours.

Bisphosphonates

Possible reduced antiresorptive response to calcitonin in patients with Paget disease previously treated with bisphosphonates.