Parathyroid Hormone

Parathyroid hormone is a prescription medication used to control hypocalcemia (low blood calcium levels) in patients with hypoparathyroidism.

Parathyroid hormone belongs to a group of drugs called hormones. These help to regulate the body’s calcium levels. Parathyroid hormone should be used with calcium and vitamin D supplementation.

This medication is available in an injectable form to be given under the skin (subcutaneous) once daily.

Common side effects of parathyroid hormone include sensations of tingling, tickling, pricking, or burning of the skin (paraesthesia), low blood calcium, headache, high blood calcium, and nausea.

Parathyroid hormone (PTH) is a prescription hormone used with calcium and vitamin D supplementation to control low blood calcium (hypocalcemia) in people with low PTH blood levels (hypoparathyroidism).

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Parathyroid Hormone may be found in some form under the following brand names:

• Natpara

Serious side effects have been reported with parathyroid hormone. See the “Parathyroid Hormone Precautions” section.

Common side effects of parathyroid hormone include the following:

• sensations of tingling, tickling, pricking, or burning of the skin (paraesthesia)
• low blood calcium
• headache
• high blood calcium
• nausea
• diarrhea
• vomiting
• joint pain
• calcium in the urine
• pain in the extremities

This is not a complete list of parathyroid hormone side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• digoxin (Lanoxin)

This is not a complete list of parathyroid hormone drug interactions. Ask your doctor or pharmacist for more information.

Serious side effects have been reported with parathyroid hormone including the following:

• Osteosarcoma (a type of bone cancer). Parathyroid hormone should not be used in patients with an increased risk of osteosarcoma.
• Severe hypercalcemia (high levels of calcium in the blood). Calcium levels should be monitored while patients are receiving parathyroid hormone.
• Severe hypocalcemia (low levels of calcium in the blood). Hypocalcemia can occur when parathyroid hormone therapy is interrupted or discontinued. Calcium levels should be monitored while patients are receiving parathyroid hormone.

Do not take parathyroid hormone if you:

• are allergic to parathyroid hormone or to any of its ingredients.

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of parathyroid hormone, there are no specific foods that you must exclude from your diet when receiving this medication.

Before taking parathyroid hormone, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• are allergic to parathyroid hormone or to any of its ingredients
• are pregnant or breastfeeding

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X - are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Parathyroid hormone falls into category C. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

Tell your doctor if you are breastfeeding or plan to breastfeed.

It is not known if parathyroid hormone crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using parathyroid hormone.

Take parathyroid hormone exactly as prescribed.

This medication is available in an injectable form to be given under the skin (subcutaneous) once daily.

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take your next dose at the regular time. You may need to take extra calcium.

Do not take 2 doses of parathyroid hormone at the same time.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

• the condition being treated
• other medical conditions you have
• other medications you are taking
• how to respond to this medication

The dose of parathyroid hormone should be individualized based on calcium levels in the blood and urine.

If you take too much parathyroid hormone, call your healthcare provider or local Poison Control Center or seek emergency medical attention right away.

If parathyroid hormone is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

• Store parathyroid hormone cartridges (mixed and unmixed) in the refrigerator, between 36°F and 46°F (2°C and 8°C). Do not freeze parathyroid hormone.
• Store away from excess heat and light.
• Keep this and all medications out of the reach of children.

WARNING: POTENTIAL RISK OF OSTEOSARCOMA

• In male and female rats, parathyroid hormone caused an increase in the incidence of osteosarcoma (a malignant bone tumor). The occurrence of osteosarcoma was dependent on parathyroid hormone dose and treatment duration. This effect was observed at parathyroid hormone exposure levels ranging from 3 to 71 times the exposure levels in humans receiving a 100 mcg dose of Natpara. These data could not exclude a risk to humans.
• Because of a potential risk of osteosarcoma, use Natpara only in patients who cannot be well-controlled on calcium and active forms of vitamin D alone and for whom the potential benefits are considered to outweigh this potential risk.
• Avoid use of Natpara in patients who are at increased baseline risk for osteosarcoma such as patients with Paget's disease of bone or unexplained elevations of alkaline phosphatase, pediatric and young adult patients with open epiphyses, patients with hereditary disorders predisposing to osteosarcoma or patients with a prior history of external beam or implant radiation therapy involving the skeleton.
• Because of the risk of osteosarcoma, Natpara is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the Natpara REMS Program.