Nplate (romiplostim) is a prescription drug that’s used to treat low platelet count. The drug comes as powder that’s made into a liquid solution for injection. It’s given once weekly.
Nplate is used in adults and certain children to treat low platelet count from the following conditions:
- immune thrombocytopenia (when other treatments, such as corticosteroids, haven’t worked well)
- acute radiation syndrome affecting the bone marrow
This article describes the dosages of Nplate, as well as its strengths and how it’s given. To learn more about Nplate, see this in-depth article.
This section describes the usual dosages of Nplate. Keep reading to learn more.
What is Nplate’s form?
Nplate comes as a powder in single-use vials. The powder is mixed with a sterile water to make a liquid solution. (In small children, it’s further diluted with saline.) A doctor or another healthcare professional injects the liquid solution under the skin.
What strengths does Nplate come in?
Nplate comes in three strengths: 125 micrograms (mcg), 250 mcg, and 500 mcg.
What are the usual dosages of Nplate?
Your doctor will start you with the recommended dosage of Nplate that provides the desired effect. Your dosage depends on the cause of the low platelet count. Your dosage for repeat treatments will also change, depending on your platelet count each week.
The information below describes dosages that are commonly used or recommended. But your doctor will determine the best dosage to fit your needs.
Dosage for immune thrombocytopenia
Doctors dose Nplate by body weight. Your first dose of Nplate for immune thrombocytopenia (ITP) is likely to be 1 mcg of Nplate for every kilogram (kg)* of body weight (1 mcg/kg).
You’ll usually receive repeat injections once per week. Each week before your injection, your doctor will order a complete blood count to check your platelet count. Depending on your platelet count, your doctor may increase or decrease your dosage, or they may delay your injection by another week.
The maximum recommended weekly dosage of Nplate is 10 mcg/kg.
* A kg is approximately 2.2 pounds (lb).
Dosage for low platelets from radiation
For treatment of low platelet count following radiation exposure, you’ll receive 10 mcg of Nplate for every kg of body weight (10 mcg/kg). This is a one-time treatment. Doctors recommend that you receive this dose as soon as possible after the radiation exposure.
What’s the dosage of Nplate for children?
Doctors can also prescribe Nplate for children with a low platelet count from ITP or radiation exposure.
Dosage for immune thrombocytopenia
Nplate may be prescribed for children ages 1 year and older for treatment of ITP.
As in adults, Nplate is dosed by body weight. The first dose will be 1 mcg of Nplate for each kg of your child’s body weight (1mcg/kg).
Injections will be repeated every week. The dosage may be adjusted, depending on your child’s platelet count. Approximately every 12 weeks, your child’s doctor will also check their body weight and adjust the dosage as necessary.
Nplate’s maximum dosage is 10 mcg/kg per week.
Dosage for radiation exposure
Newborns and children who have been exposed to radiation may be treated with Nplate. The recommended dosage is a one-time dose of 10 mcg/kg.
For more information about Nplate’s dosage for children, talk with your child’s doctor or a pharmacist.
Is Nplate used long term?
If you’re prescribed Nplate for ITP, you might take the drug long term. This will depend on how your body responds to treatment with Nplate. It also depends on your platelet count and whether you have acute, persistent, or chronic ITP.
For example, children commonly have acute ITP. With acute ITP, platelet counts return to normal within 3 months. And 80% of children with ITP won’t go on to have chronic ITP (low platelet counts for more than 12 months).
Some adults also experience treatment-free remission. This means your platelet count stays within the normal range after you’ve stopped taking Nplate. (You should not stop your treatment without first discussing this with your doctor.)
If you have questions about how long you’re likely to receive Nplate to treat ITP, talk with your doctor.
Note: If you’re prescribed Nplate following radiation exposure, you’ll receive a one-time dose.
The dosage of Nplate you’re prescribed may depend on several factors. These include:
- the type and severity of the condition the drug is being used to treat
- your body weight
- how you respond to Nplate (your platelet count)
Nplate comes as a powder in single dose vials. The powder is mixed with sterile water to make a liquid solution. When the calculated dose is less than 23 micrograms (mcg), saline solution will also be added to the liquid solution.
Your doctor (or another healthcare professional) will inject the small amount of liquid solution under your skin.
You’ll receive these injections at your doctor’s office or another medical facility on a weekly basis.
If you miss your appointment to receive Nplate, call your doctor’s office as soon as possible to reschedule.
The sections above describe the usual dosages provided by the manufacturer. If your doctor recommends Nplate for you, they’ll prescribe the dosage that’s right for you.
Talk with your doctor if you have questions or concerns about your current dosage.
Here are some examples of questions you may want to ask your doctor:
- Does my risk of developing a blood clot increase with higher doses of Nplate?
- Would I need a different dosage if I’m taking other medications for my condition?
- How does the dosage of Nplate compare with Promacta (eltrombopag)?
To learn more about Nplate, see these articles:
To get information on different conditions and tips for improving your health, subscribe to any of Healthline’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.
Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.