Understanding Cinacalcet and Its Brand Names
Cinacalcet is the generic name for a medication primarily known by its brand name, Sensipar [1.2.1, 1.2.4]. As a calcimimetic agent, it works by mimicking the effect of calcium on the body's tissues [1.3.5]. This action is crucial for patients with certain disorders related to the parathyroid glands. While Sensipar is the most common name in the United States, other international brand names include Mimpara and Regpara [1.2.3, 1.2.6]. Since becoming available as a generic, it is also marketed under its chemical name, cinacalcet [1.2.2].
How Cinacalcet Works: The Mechanism of Action
Cinacalcet's primary function is to lower elevated levels of parathyroid hormone (PTH) in the blood [1.3.4]. It achieves this through a specific mechanism of action:
- Targeting the Calcium-Sensing Receptor (CaSR): The surface of the parathyroid gland's chief cells contains calcium-sensing receptors. These receptors are the main regulators of PTH synthesis and secretion [1.3.4].
- Increasing Receptor Sensitivity: Cinacalcet is an allosteric activator of the CaSR. This means it binds to the receptor and increases its sensitivity to the calcium already present in the bloodstream [1.3.5, 1.3.7].
- Suppressing PTH Secretion: By making the CaSR more sensitive, the parathyroid gland is 'tricked' into thinking there is more calcium than there actually is. This signals the gland to decrease its production and release of PTH [1.3.4].
- Lowering Serum Calcium and Phosphorus: The reduction in PTH leads to a corresponding decrease in blood calcium levels [1.3.4]. In patients with chronic kidney disease, this also helps lower phosphorus levels [1.2.4].
The peak effect of cinacalcet, marked by the lowest point (nadir) in PTH levels, occurs approximately 2 to 6 hours after taking a dose [1.3.4].
Primary Uses and Indications for Cinacalcet
Clinicians prescribe cinacalcet for specific conditions characterized by excess parathyroid hormone and high calcium levels [1.5.7].
Secondary Hyperparathyroidism (SHPT) in CKD Patients
This is the most common use for cinacalcet. It is indicated for treating SHPT in adult patients with chronic kidney disease (CKD) who are on dialysis [1.2.5, 1.5.1]. In these patients, failing kidneys disrupt the balance of calcium and phosphorus, leading the parathyroid glands to become overactive. Cinacalcet helps restore this balance by lowering PTH [1.5.5]. It is important to note that cinacalcet is generally not indicated for CKD patients who are not on dialysis due to an increased risk of hypocalcemia (low calcium levels) [1.2.5].
Parathyroid Carcinoma
Cinacalcet is used to treat hypercalcemia (abnormally high levels of calcium in the blood) in patients with parathyroid cancer [1.4.3]. This cancer causes the parathyroid gland to secrete excessive amounts of PTH, leading to dangerously high calcium levels. Cinacalcet helps to control this by reducing PTH secretion [1.5.1].
Primary Hyperparathyroidism
For some patients with primary HPT, surgery (parathyroidectomy) to remove the overactive gland(s) is the standard treatment. However, cinacalcet is an option for treating severe hypercalcemia in adult patients for whom surgery is not a viable option, either because they are unable to undergo the procedure or it is contraindicated [1.4.3, 1.5.3].
Common and Serious Side Effects
Like all medications, cinacalcet has potential side effects. The most common are gastrointestinal in nature [1.4.3].
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Common Side Effects: Nausea and vomiting are very common, affecting a significant percentage of patients [1.2.2]. Other common effects include diarrhea, dizziness, muscle pain, and weakness [1.2.2, 1.4.3].
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Serious Side Effects: Patients should be aware of more serious risks that require immediate medical attention.
- Hypocalcemia (Low Calcium): Because cinacalcet lowers calcium, it can sometimes drop to dangerously low levels. Symptoms include muscle cramps, spasms, seizures, and a tingling or pins-and-needles sensation around the mouth or in the fingers and toes [1.2.2, 1.4.1]. This is a significant risk, and regular blood tests are required to monitor calcium levels [1.4.4].
- Upper Gastrointestinal Bleeding: Cases of stomach bleeding have been reported. Signs include vomiting blood, black or tarry stools, and severe stomach pain [1.4.1].
- Heart Problems: In some cases, particularly in patients with a history of heart issues, cinacalcet has been linked to abnormal heartbeats, worsening heart failure, and low blood pressure [1.2.2].
- Adynamic Bone Disease: If PTH levels are suppressed too much (below 100 pg/mL), it can lead to adynamic bone disease, a condition where bone turnover is extremely low, increasing fracture risk [1.4.6].
Comparing Cinacalcet to Other Treatments
Cinacalcet is one of several options for managing hyperparathyroidism. Its main alternatives include vitamin D sterols and another calcimimetic, etelcalcetide.
| Feature | Cinacalcet (Sensipar) | Etelcalcetide (Parsabiv) | Vitamin D Analogs (e.g., Paricalcitol) |
|---|---|---|---|
| Administration | Oral tablet, taken daily with food [1.2.2, 1.3.4] | Intravenous (IV), typically administered at the end of hemodialysis sessions [1.6.2] | Oral or IV [1.2.7] |
| Mechanism | Calcimimetic: Increases sensitivity of calcium-sensing receptors [1.3.5] | Calcimimetic: Increases sensitivity of calcium-sensing receptors [1.6.6] | Binds to vitamin D receptors to lower PTH [1.2.7] |
| Efficacy | Effective at lowering PTH, calcium, and phosphorus [1.3.8] | Shown to be more effective than cinacalcet in reducing PTH levels in head-to-head trials [1.6.1, 1.6.7] | Effective at lowering PTH, but can increase calcium and phosphorus levels [1.2.7] |
| Key Side Effect | Hypocalcemia, nausea, vomiting [1.2.2] | Hypocalcemia (potentially higher rates than cinacalcet), heart failure events [1.6.1, 1.6.5] | Hypercalcemia (high calcium) and hyperphosphatemia (high phosphorus) [1.2.7] |
Real-world studies suggest etelcalcetide may achieve better PTH control, partly because its IV administration during dialysis ensures 100% adherence, bypassing issues with patients remembering to take an oral pill daily [1.6.2, 1.6.3]. The choice between these agents often depends on patient adherence, tolerability, cost, and specific clinical circumstances [1.6.5].
Conclusion
In summary, another name for cinacalcet is its widely recognized brand name, Sensipar [1.2.1]. This vital medication plays a key role as a calcimimetic, managing serious conditions like secondary hyperparathyroidism in dialysis patients and hypercalcemia from parathyroid cancer by increasing the sensitivity of the calcium-sensing receptor to lower PTH production [1.3.4, 1.4.1]. While effective, its use requires careful monitoring by a healthcare team to manage potential side effects, most notably hypocalcemia [1.4.5]. With the availability of both generic oral forms and an alternative intravenous calcimimetic, etelcalcetide, clinicians can tailor treatment to best suit patient needs.
For more information from an authoritative source, visit the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): https://www.niddk.nih.gov/health-information/kidney-disease/chronic-kidney-disease-ckd/mineral-bone-disorder
