Medically reviewed by Drugs.com. Last updated on Feb 4, 2022.
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 parathyroid hormone. These data could not exclude a risk to humans.Because of a potential risk of osteosarcoma, use parathyroid hormone 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 parathyroid hormone 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, parathyroid hormone is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the NATPARA REMS Program .
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
- Powder for Solution
Therapeutic Class: Endocrine-Metabolic Agent
Pharmacologic Class: Parathyroid
Uses for Natpara
Parathyroid hormone injection is used together with calcium and vitamin D to control hypocalcemia (low calcium levels) in patients with hypoparathyroidism. Hypoparathyroidism is a condition that is caused when the parathyroid gland in the neck doesn't make enough parathyroid hormone (PTH).
This medicine is only available through a restricted access program. Doctors who are enrolled in the restricted program can write a prescription for this medicine.
Before using Natpara
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of parathyroid hormone injection in the pediatric population. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of parathyroid hormone injection in the elderly. However, elderly patients are more likely to have kidney problems, which may require caution and an adjustment in the dose for patients receiving this medicine.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Bone disease (eg, osteosarcoma, Paget's disease of bone)—Use with caution. May make this condition worse.
- Kidney disease—Use with caution. The effects may be increased because of slower removal of the medicine to the body.
Proper use of Natpara
A doctor or other trained health professional will give you this medicine. This medicine is given as a shot under your skin, usually on the upper thighs.
You may be taught how to give this medicine at home. Make sure you understand all of the instructions before giving yourself an injection. Do not use more medicine or use it more often than your doctor tells you to.
This medicine comes with a Medication Guide and patient instructions. Read and follow the instructions carefully. Ask your doctor if you have any questions about:
- How to prepare the injection using the medication cartridge and mixing device.
- The proper use of disposable syringes.
- How to give the injection using the reusable Q-Cliq pen injector.
- How long the injection can be stored at home.
If you have any questions about any of this, check with your doctor.
The medicine should be clear. Do not use the medicine if it is cloudy, discolored, or has large particles in it.
Follow your doctor's instructions about how to take vitamin D and calcium supplements while using this medicine.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For injection dosage form:
- For low calcium levels:
- Adults—Dose must be determined by your doctor. The starting dose is usually 50 microgram (mcg) injected under the skin once a day. Your doctor may adjust your dose every 4 weeks as needed. However, the dose is usually not more than 100 mcg per day.
- Children—Use and dose must be determined by your doctor.
- For low calcium levels:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Store in the refrigerator. Do not freeze.
After mixing Natpara®, store the medication cartridge in the Q-Cliq pen in the refrigerator for up to 14 days. Store away from heat and light. Do not freeze or shake. Throw away any unused mixed medicine in the medication cartridges after 14 days.
Throw away used needles in a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.
Precautions while using Natpara
It is important that your doctor check your progress at regular visits to make sure this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.
Do not use this medicine together with alendronate (Fosamax®).
This medicine may increase your risk of having osteosarcoma (bone tumor). This is more likely to occur if you have Paget's disease of the bone, high levels of alkaline phosphatase, genetic disorders, children with open epiphyses, or a history of external beam or implant radiation therapy. Tell your doctor right away if you have bone pain that does not go away or a new soft tissue mass that is tender to palpitation.
Severe hypercalcemia (high calcium in the blood) may occur while using this medicine. This is more likely to occur when you start treatment or increase your dose. Call your doctor right away if you have confusion, constipation, dry mouth, metallic taste, muscle weakness, nausea or vomiting, or weight loss.
Do not stop using this medicine suddenly without asking your doctor. This may increase your risk of having severe hypocalcemia (low calcium in the blood). Symptoms include abdominal or stomach cramps, muscle spasms or twitching, numbness or tingling in your fingers, toes, or around your mouth, or trouble breathing.
Do not take other medicines unless they have been discussed with your doctor. Taking other medicines (especially digoxin, Lanoxin®) together with Natpara® may require your doctor to change the dose of one of the medicines.
Natpara side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Abdominal or stomach cramps or pain
- blurred vision
- difficulty with breathing
- dry mouth
- incoherent speech
- increased urination
- irregular heartbeats
- loss of appetite
- metallic taste
- muscle cramps in the hands, arms, feet, legs, or face
- muscle weakness
- numbness and tingling around the mouth, fingertips, or feet
- pounding in the ears
- slow or fast heartbeat
- unusual tiredness
- weight loss
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Abnormal or decreased touch sensation
- body aches or pain
- difficulty with moving
- ear congestion
- loss of voice
- muscle pain or stiffness
- pain in the joints or neck
- pain or tenderness around the eyes and cheekbones
- sore throat
- stuffy or runny nose
- tightness of the chest
- upper abdominal or stomach pain
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
More about Natpara (parathyroid hormone)
- Side effects
- Drug interactions
- Dosage information
- During pregnancy
- Reviews (6)
- Pricing & coupons
- En español
- Drug class: parathyroid hormone and analogs
- FDA approval history
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