How Do Calcimimetics Work?

Calcimimetics (drugs that mimic the action of calcium on tissues) are a class of drugs used to treat hyperparathyroidism (a condition in which the parathyroid glands produce a high amount of parathyroid hormone [PTH]) in patients with chronic kidney disease (gradual loss of kidney function) who are being treated with dialysis (a procedure to remove waste products and excess fluid from the blood when the kidneys stop working properly) and to treat high levels of calcium in patients who have parathyroid cancer (parathyroid glands are two pairs of small, oval-shaped glands located behind the thyroid glands).

Calcimimetics work by decreasing the levels of PTH (responsible for maintaining proper levels of both calcium and phosphorus in the body). The right amount of these substances in the body helps to prevent progressive bone disease. Increased PTH stimulates osteoclastic activity, resulting in cortical bone resorption (remodeling of bones) and marrow fibrosis.

Hyperparathyroidism (overactive parathyroid gland) is a condition in which one or more of the parathyroid glands become overactive and release a high amount of PTH. This increases the calcium levels in the blood, a condition known as “hypercalcemia” and the symptoms include:

• Joint pain
• Tiredness
• Muscle weakness
• Loss of appetite
• Trouble concentrating
• Depression
• Nausea 
• Vomiting
• Increased thirst
• Frequent urination
• Constipation
• Bone pain
• Forgetfulness
• Osteoporosis (thinning bones)
• Reduced kidney function
• High blood pressure

Calcimimetics work in the following ways:

• Reduce the amount of PTH, calcium, and phosphorous in the body.
• Act directly to lower PTH levels by increasing the sensitivity of the calcium-sensing receptors to activation by extracellular calcium, inhibiting PTH secretion.
• Reduction in PTH is associated with a concomitant decrease in serum calcium levels.

Calcimimetics are used in conditions such as:

• Primary hyperparathyroidism (a condition in which the parathyroid glands produce a high amount of PTH, which causes high blood calcium level)
• Secondary hyperparathyroidism (overactivity of the parathyroid glands occurs in response to another medical condition that causes calcium loss)
• Parathyroid carcinoma (a rare disease in which malignant [cancer] cells form in the tissues of a parathyroid gland)

Some of the common side effects include:

• Diarrhea
• Nausea
• Vomiting
• Myalgia (muscle pain)
• Stomach upset
• Weakness
• Abdominal pain

Other rare side effects include:

• Chest pain
• Dizziness (feeling faint, weak, or unsteady)
• Seizures (a sudden, uncontrolled electrical disturbance in the brain)
• Hypertension (high blood pressure)
• Anorexia (lack or loss of appetite)
• Asthenia (abnormal physical weakness or lack of energy)
• Infection of dialysis access (surgically created blood vessel where the blood leaves and enters the body during dialysis)
• Numb/tingling skin
• Severe muscle spasms
• Unusual tiredness
• Fast/irregular/pounding heartbeat

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of calcimimetics include:

• Cinacalcet
• Sensipar