Cinacalcet

(sin-uh-kal-set)

Trade/other name(s): Sensipar, cinacalcet hydrochloride

Why would this drug be used?

Cinacalcet is used to lower high blood calcium levels in people who have cancer of the parathyroid gland. It is also used to treat overactive parathyroid glands in people with chronic kidney disease.

How does this drug work?

The parathyroid glands help regulate the amount of calcium in the blood. They are very sensitive to blood calcium levels. Normally, if calcium levels are too low, the glands secrete parathyroid hormone (PTH), which causes some calcium to be released from the bones. Parathyroid cancer can cause too much PTH to be made, which results in too much calcium in the blood (hypercalcemia).

Cinacalcet works by making parathyroid cells more sensitive to calcium. This makes them less likely to secrete PTH, which in turn lowers calcium levels.

Before taking this medicine

Tell your doctor…

• If you are allergic to anything, including medicines, dyes, additives, or foods.
• If you have ever had seizures. Cinacalcet may make you more likely to have seizures.
• If you have a history of liver disease (including hepatitis). This drug is cleared from the body mainly by the liver. Reduced liver function may result in more drug than expected staying in the body, which could lead to unwanted side effects. Your doctor may need to adjust your dose accordingly.
• If you have any other medical conditions such as kidney disease, heart disease, congestive heart failure, lung disease, diabetes, gout, or infections. You may need closer monitoring of these conditions while being treated. Some people may not be able to use this drug at all.
• If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. It is not known if this drug might cause problems if either the male or female is taking it at the time of conception or during pregnancy. Men and women who are taking this drug should use some kind of birth control during treatment. It is important to check with your doctor about what kinds of birth control can be used with this medicine. This drug should be used during pregnancy only if the potential benefit is thought to justify the potential risk to the fetus.
• If you are breast-feeding. While no studies have been done in humans, this drug may pass into breast milk and affect the baby. Talk with your doctor about the possible risks of breast-feeding while taking this drug.
• About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Some drugs may raise the blood levels of cinacalcet and cause a higher risk of side effects, including:

• the anti-fungal drugs ketoconazole (Nizoral) and itraconazole (Sporanox)
• antibiotics clarithromycin (Biaxin) and erythromycin (EES)

The blood levels of other drugs may also be affected by cinacalcet. Your doctor may need to adjust the doses of these medicines while you are on cinacalcet to avoid dangerous side effects:

• tricyclic antidepressants such as amitriptyline (Elavil), nortriptyline (Pamelor), desipramine (Norpramin), doxepin (Sinequan), and others
• anti-cancer drugs vinblastine (Velban) and tamoxifen (Nolvadex)
• the heart rhythm drug flecainide (Tambocor)
• thioridazine (Mellaril), a drug for certain mental illnesses
• the blood pressure medicines metoprolol (Lopressor) and carvedilol (Coreg)

There are other drugs that may affect or be affected by cinacalcet. Check with your doctor, nurse, or pharmacist about all of your medicines, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with foods are known at this time. Check with your doctor, nurse, or pharmacist about whether these or other foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Cinacalcet is taken as a pill. For high blood calcium levels due to parathyroid cancer, the usual starting dose is one 30 milligram (mg) tablet taken twice a day. It should be taken with food or right after a meal. Tablets should be swallowed whole, and not cut, split, or crushed. The dose may need to be adjusted based on your liver function.

Your doctor will track your blood calcium levels carefully and may adjust your dose every few weeks based on these levels.

Store the medicine in a tightly closed container away from heat and moisture and away from children and pets.

Precautions

In some cases, taking this drug could lead to low blood calcium levels (hypocalcemia). Possible symptoms could include muscle spasms or cramps, muscle or joint pains, changes in sensations on the face, hands or feet, confusion, or seizures. Tell your doctor right away if you notice any of these symptoms.

This drug may raise your risk of seizures, especially if you have had seizures in the past. Be sure your doctor knows about this.

Your doctor will test your blood often throughout your treatment, looking for possible effects of the drug on blood chemistry levels (especially calcium levels). Based on the test results, your doctor may need to change your next dose of this drug.

A few people had problems with low blood pressure, heart failure, or abnormal heartbeat while taking cinacalcet. Call your doctor if you notice dizziness, swelling in your feet or ankles, shortness of breath, or irregular heart beat.

Possible side effects

You will probably not have most of the following side effects. Should you have any of these side effects talk to your doctor or nurse. They can help you understand these side effects and cope with them.

Common

• nausea
• vomiting

Less common

• diarrhea
• feeling dizzy or faint*
• muscle aches
• high blood pressure

Rare

• muscle pain, cramps, or spasms*
• low blood pressure*
• abnormal heartbeat*
• heart failure, with symptoms like swelling feet and ankles, shortness of breath*
• abnormal sensations on the face, hands, or feet*
• allergic reactions with symptoms like swelling of the mouth, face, or throat; itching; hives; faintness or dizziness; trouble breathing or swallowing
• seizures*

*See "Precautions" section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 2004.

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.