Cinacalcet
Calcimimetics
Calcimimetics
An oral calcimimetic that lowers PTH and calcium in dialysis patients with secondary hyperparathyroidism and in parathyroid cancer.
Quick facts
- Group
- Calcimimetics
- Target
- Calcium-sensing receptor (CaSR), a G-protein–coupled receptor of the parathyroid gland
- Used for
- Secondary hyperparathyroidism · Hypercalcaemia
- Key effects
- Nausea and vomiting · Diarrhoea · Dizziness
- Monitor
- Serum calcium within a week · Intact PTH · Phosphate
- ATC
- H05BX01
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows cinacalcet itself in the transmembrane domain of the human calcium-sensing receptor (cryo-EM).
Cinacalcet binds the transmembrane part of the calcium-sensing receptor on parathyroid chief cells and makes it more sensitive to extracellular calcium. The gland responds as if calcium were higher and secretes less PTH. Lower PTH reduces bone resorption and renal calcium reabsorption, so serum calcium and the calcium-phosphate product fall.
- Cinacalcet binds the calcium-sensing receptor of the parathyroid
- The receptor now responds to lower calcium
- Chief cells release less PTH
- PTH, calcium and the calcium-phosphate product fall
Indications
- Secondary hyperparathyroidism in adults with chronic kidney disease on dialysis CKD-mineral and bone disorder (renal osteodystrophy) →
- Hypercalcaemia in parathyroid carcinoma
- Hypercalcaemia in primary hyperparathyroidism when parathyroidectomy is not possible Primary hyperparathyroidism →
Adverse effects
Common
- Nausea and vomiting
- Diarrhoea
- Dizziness
- Weakness
- Chest pain
Contraindications
- Starting it when serum calcium is below the lower limit of normal
Key interactions
- Drugs metabolised by CYP2D6 with a narrow margin (flecainide, most tricyclic antidepressants, some beta-blockers)
- Cinacalcet inhibits CYP2D6 strongly and raises their levels
- Strong CYP3A4 inhibitors (ketoconazole)
- Higher cinacalcet levels
- Other drugs that lower calcium (e.g. denosumab)
- More risk of hypocalcaemia
What is monitored
- Serum calcium within a week of starting or changing the dose, then regularly
- Intact PTH, measured at least 12 hours after a dose
- Phosphate
- ECG/QT in people at risk
- Signs of gastrointestinal bleeding; seizures in people with epilepsy
Administration and safety
- Oral tablet once a day, with food or shortly after a meal
- Swallowed whole, not split, chewed or crushed
- Not started if calcium is below normal; often combined with vitamin D sterols and phosphate binders
Pregnancy and breastfeeding
Human data are limited; it is used in pregnancy only if the benefit justifies the risk.
Nursing care
- Check calcium before the dose; hold and report if it is low
- Teach signs of low calcium: tingling of lips or fingers, cramps, muscle spasms
- Ask about seizures, heart failure and long QT before starting
- Ask about vomiting blood or black stools
- Review other drugs for CYP2D6 interactions
Pharmacokinetics
- Absorption
- Oral; food, especially a high-fat meal, increases absorption
- Metabolism
- In the liver by CYP3A4, CYP2D6 and CYP1A2; it is itself a strong CYP2D6 inhibitor
- Half-life
- Terminal half-life of about 30 to 40 hours, allowing once-daily use
Test yourself
Think of the answer, then tap the question to see it.
Why must cinacalcet be taken with food?
Food, especially fat, increases its absorption; the label tells it to be taken with or shortly after a meal.
When is intact PTH measured in a person on cinacalcet?
At least 12 hours after a dose.
A patient on cinacalcet also takes flecainide. What is the concern?
Cinacalcet strongly inhibits CYP2D6, so flecainide levels rise and toxicity becomes more likely.
What is the contraindication to starting cinacalcet?
A serum calcium below the lower limit of normal.
Connections
← Back to the class: Calcimimetics
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - CINACALCET tablet (DailyMed (U.S. National Library of Medicine), 2026); Cinacalcet: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.