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Generic Name: parathyroid hormone (PAR a THY roid HOR mone)
Brand Names: Natpara

Medically reviewed on Mar 5, 2018

What is Natpara?

Natpara (parathyroid hormone) is a manmade form of a hormone that occurs naturally in the body.

Natpara is used together with calcium and vitamin D to treat hypocalcemia (low levels of calcium in the blood) in people who also have low levels of parathyroid hormone.

Natpara is usually given after calcium and vitamin D alone have been tried without success.

Natpara is available only from a certified pharmacy under a special program. You must be registered in the program and understand the risks and benefits of taking this medicine.

Important information

In animal studies, parathyroid hormone caused bone cancer. However, it is not known whether these effects would occur in humans. Ask your doctor about your risk.

Before taking this medicine

To make sure Natpara is safe for you, tell your doctor if you have:

  • high levels of calcium in your blood;

  • high levels of alkaline phosphatase in your blood;

  • a history of bone cancer;

  • Paget's disease or other bone disorders; or

  • if you have ever had a radiation treatment.

It is not known whether Natpara will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether parathyroid hormone passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

Natpara is not approved for use by anyone younger than 18 years old.

How should I use Natpara?

Take Natpara exactly as prescribed by your doctor. Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Natpara is injected under the skin. You may be shown how to use injections at home. Do not self-inject this medicine if you do not understand how to give the injection and properly dispose of used needles and syringes.

Natpara should be given using only the cartridges and injection pen provided with the medicine. Do not use a syringe to inject Natpara.

Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.

Each Natpara cartridge contains enough medicine for 14 separate injections. Throw the cartridge away after 14 uses, even if there is still some medicine left in the cartridge.

Do not throw away the injection pen. It can be used for up to 2 years if you change the cartridge every 14 days.

Do not shake the cartridge or you may ruin the medicine. Prepare your dose only when you are ready to give an injection. Do not use if the medicine has changed colors or has particles in it. Call your pharmacist for new medicine.

You should not stop using Natpara suddenly. Stopping suddenly may make your condition worse.

While using Natpara, you may need frequent blood tests.

Store in the refrigerator, do not freeze. Protect from heat and light.

Natpara dosing information

Usual Adult Dose for Hypocalcemia:

50 mcg subcutaneously once a day

-The injection should be given in the thigh (alternate thigh every day).

Use: An adjunct to calcium and vitamin D to control hypocalcemia in patients with hypoparathyroidism.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Natpara?

Follow your doctor's instructions about any restrictions on food, beverages, or activity. Tell your doctor if you drink milk or eat dairy products (cheese, yogurt, sour cream) or other foods high in calcium.

Natpara side effects

Get emergency medical help if you have signs of an allergic reaction to Natpara: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • new or unusual pain that is ongoing;

  • swelling or tender lumps under your skin;

  • high calcium--nausea, vomiting, constipation, increased thirst or urination, muscle pain or weakness, bone pain, confusion, and feeling tired or restless; or

  • low calcium--numbness or tingly feeling around your mouth, fast or slow heart rate, muscle tightness or contraction, overactive reflexes.

Common Natpara side effects may include:

  • tingling, burning, or prickly feeling in your skin;

  • headache;

  • nausea, vomiting, diarrhea; or

  • joint pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Natpara?

Tell your doctor about all your current medicines and any you start or stop using, especially:

  • alendronate (Fosamax);

  • digoxin; or

  • vitamin or mineral supplements that contain calcium or vitamin D.

This list is not complete. Other drugs may interact with parathyroid hormone, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Natpara only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.