Calcitonin Salmon
Calcitonin salmon is a synthetic polypeptide hormone primarily used in veterinary medicine to manage severe **hypercalcemia** (e.g., secondary to cholecalciferol rodenticide toxicity, apocrine gland anal sac adenocarcinoma, or lymphoma) and nutritional secondary hyperparathyroidism (NSHP) in reptiles. It may also be used as an adjunctive treatment for severe bone pain. * **Clinical Pearl**: Salmon calcitonin is utilized therapeutically because it is approximately 50 times more potent and has a longer duration of action than mammalian (human) calcitonin. * **Limitation**: Its clinical utility is often limited by expense and the rapid development of **tachyphylaxis** (downregulation of receptors), meaning it typically loses efficacy after a few days of continuous treatment. * **Caution**: Do not confuse calcitonin (which lowers serum calcium) with calcitriol (which raises serum calcium).
Mechanism: Calcitonin exerts a multitude of physiologic effects to rapidly lower serum calcium levels: * **Bone**: Binds directly to **calcitonin receptors** on osteoclasts → profoundly inhibits osteoclastic bone resorption → decreases the release of calcium and phosphorus from bone into the extracellular fluid. * **Kidneys**: Acts on the renal tubules → reduces tubular reabsorption of calcium, phosphate, sodium, magnesium, potassium, and chloride → promotes their renal excretion. * **Gastrointestinal Tract**: Increases jejunal secretion of water, sodium, potassium, and chloride (but notably not calcium).
Dosing by species
- Hypervitaminosis D (toxicity)/hypercalcemia · 4-8 Units/kg · SC · two to three times a day · Effects are short-lived and multiple treatments are required.
- Hypervitaminosis D (toxicity)/hypercalcemia · 4-6 Units/kg · SC · q2-3 hours · until serum calcium levels are normalized
- Adjunctive therapy if fluid deficit replacement, saline diuresis, furosemide and prednisone have failed to control calcium · 4 Units/kg IV, then 4-8 Units/kg SC · IV, then SC · q12-24h
- Hypervitaminosis D (toxicity)/hypercalcemia · 4-6 Units/kg · SC · q8-12h
- Hypercalcemia (Green iguanas) · 1.5 Units/kg · SC · q8h · for several weeks if necessary · In combination with fluid therapy
- Nutritional secondary hyperparathyroidism (NSHP) · 50 Units/kg · IM · once weekly · for 2-3 doses · Use if reptile is not hypocalcemic.
- Nutritional secondary hyperparathyroidism (NSHP) · 50 Units/kg · IM · weekly · for 2-3 doses · Correct husbandry problems and correct hypocalcemia with calcium and vitamin D first. Once calcium level is normal and patient is on oral calcium supplementation (usually about 7 days after starting therapy) give calcitonin. Supportive care can be tapered off once patient becomes stable.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Hypersensitivity to calcitonin
- Patients with a history of hypersensitivity to other proteins may be at risk
Adverse effects
- Anorexia
- Vomiting
- Hypocalcemia (with overmedication)
- Diarrhea
- Injection site pain and swelling
- Redness
- Peripheral paresthesias (reported in humans)
- Allergic reactions (rare)
- Tachyphylaxis (resistance to therapy over time)
Drug interactions
- Vitamin D analogs · May interfere with the efficacy of calcitonin
- Calcium products · May interfere with the efficacy of calcitonin
Monitoring
- Serum Calcium
Overdose
Very limited data is available. Nausea and vomiting have been reported after accidental overdose injections. Chronic overdosing can lead to severe **hypocalcemia**.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.