Cinacalcet is a calcimimetic agent used primarily to manage secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) on dialysis, and to treat parathyroid carcinoma or severe primary hyperparathyroidism when surgery is not an option.
Pharmacologic Profile:
- Mechanism of Action: Cinacalcet increases the sensitivity of the calcium-sensing receptors (CaSR) on the parathyroid gland to extracellular calcium. This leads to a decrease in parathyroid hormone (PTH) secretion, which in turn lowers serum calcium and phosphate levels.
- Drug Class: Calcimimetic
- Route of Administration: Oral
Clinical Indications:
- Secondary hyperparathyroidism in CKD patients on dialysis
- Hypercalcemia in parathyroid carcinoma
- Severe primary hyperparathyroidism when parathyroidectomy is not feasible
Pharmacokinetics:
- Metabolism: Primarily via CYP3A4, CYP2D6, and CYP1A2
- Half-life: ~30–40 hours
- Protein Binding: ~93–97%
Monitoring Parameters: Serum calcium (risk of hypocalcemia), PTH levels, Serum phosphate, Signs of adynamic bone disease with overtreatment
Common Adverse Effects: Hypocalcemia (may be symptomatic: muscle cramps, paresthesia, seizures), Nausea, vomiting, Myalgia, QT prolongation (in setting of hypocalcemia)
Drug Interactions:
- CYP3A4 inhibitors/inducers may affect plasma levels
- Use caution with medications that lower serum calcium or prolong QT interval