Understanding ITP

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Managing Your Platelet Count

Because ITP causes a drop in the number of plateletsSmall cells that are made in the bone marrow and circulate through the bloodstream. Whenever there is damage to a blood vessel, platelets stick to the area to stop or prevent bleeding. in the bloodstream, your healthcare providers will pay close attention to your platelet countsA measure of how many platelets are in the blood, usually expressed in thousands per microliter (e.g., 50,000) or in 109 per liter (e.g., 50 x 109/L). A count of 50 x 109/L is equal to a count of 50,000 per microliter. when deciding if and when to treat and measuring how well treatment is working.

Defining your platelet range

A healthy person will typically have a platelet count of 150,000 to 450,000 per microliter of blood.1 Patients with ITP have platelet counts that are less than 100,000 per microliter.2 Even when you are on therapy that works for you, platelet counts can vary slightly from week to week, which is why your healthcare provider may try to raise your platelet count to at least 50,000 per microliter and keep it at that level. Bruising and other bleeding symptoms most often occur at platelet counts less than 20,000 per microliter.3

Your healthcare provider may work to keep your platelet counts within a range sufficient to reduce the risk of bleeding, rather than trying to hit an exact platelet count.4

Treatment goals

Generally, the most important goal among healthcare providers treating ITP is to reduce the risk for serious bleeding by increasing platelet counts. Another goal may be to relieve the symptoms of chronic ITP, such as bruising, while keeping in mind the potential side effects of treatment.5

Next: Treatments for ITP >

Indication

Nplate® is a man-made protein medicine used to treat low blood platelet counts in adults with chronic immune thrombocytopenia (ITP), when certain other medicines, or surgery to remove your spleen, have not worked well enough.

Nplate® is not for use in people with a precancerous condition called myelodysplastic syndrome (MDS) or low platelet count caused by any condition other than chronic (lasting a long time) immune thrombocytopenia (ITP). Nplate® is only used if your low platelet count and medical condition increase your risk of bleeding. Nplate® is used to try to keep your platelet count about 50,000 per microliter in order to lower the risk for bleeding. Nplate® is not used to make your platelet count normal.

Important Safety Information

What is the most important information I should know about Nplate®?

Nplate® can cause serious side effects:

Worsening of a precancerous blood condition to a blood cancer (leukemia): Nplate® is not for use in people with a precancerous condition called myelodysplastic syndromes (MDS) or for any condition other than chronic (lasting a long time) immune thrombocytopenia (ITP). If you have MDS and receive Nplate®, your MDS condition may worsen and become an acute leukemia. If MDS worsens to become acute leukemia you may die sooner from the acute leukemia.

Higher risk for blood clots:

  • You may have a higher risk of getting a blood clot if your platelet count becomes high during treatment with Nplate®. You may have severe complications or die from some forms of blood clots, such as clots that spread to the lungs or that cause heart attacks or strokes. Your healthcare provider will check your blood platelet counts and change your dose or stop Nplate® if your platelet counts get high.
  • If you have a chronic liver disease, you may get blood clots in the veins of your liver. This may affect your liver function.

Bone marrow changes (increased reticulin and possible bone marrow fibrosis): Nplate® may cause changes in your bone marrow, but these changes may improve if you stop taking Nplate®. These changes may lead to abnormal blood cells or your body making less blood cells. The mild form of these bone marrow changes is called "increased reticulin." It is not known if this may progress to a more severe form called "fibrosis." The mild form may cause no problems while the severe form may cause life-threatening blood problems. Signs of bone marrow changes may show up as abnormalities in your blood tests. Your healthcare provider will decide if abnormal blood tests mean that you should have bone marrow tests or if you should stop taking Nplate®.

Worsening low blood platelet count (thrombocytopenia) and risk of bleeding shortly after stopping Nplate®: When you stop receiving Nplate®, your low blood platelet count (thrombocytopenia) may become worse than before you started receiving Nplate®. These effects are most likely to happen shortly after stopping Nplate® and may last about 2 weeks. The lower platelet counts during this time period may increase your risk of bleeding, especially if you are taking a blood thinner or other medicine that affects platelets. Your healthcare provider will check your blood platelet counts for at least two weeks after you stop taking Nplate®. Call your healthcare provider right away to report any bruising or bleeding.

Lack or loss of response: If you do not experience results from Nplate®, your body may have created cells that are counteractive to Nplate®. Your healthcare provider will monitor your platelet counts and test your blood regularly to determine if this is an issue.

Blood test monitoring: Your healthcare provider will check your platelet count every week and change your dose of Nplate® as needed. This will continue until your healthcare provider decides that your dose of Nplate® can stay the same. After that, you will need to have blood tests every month. When you stop receiving Nplate®, you will need blood tests for at least 2 weeks to check if your platelet count drops too low.

What are the possible side effects of Nplate®?

  • Nplate® may cause serious side effects. See "What is the most important information I should know about Nplate®?"
  • The most common side effects of Nplate® are:
    • Headache
    • Joint pain
    • Dizziness
    • Trouble sleeping
    • Muscle tenderness or weakness
    • Pain in arms and legs
    • Abdominal pain
    • Shoulder pain
    • Indigestion
    • Tingling or numbness in hands and feet
  • These are not all the possible side effects of Nplate®. Tell your healthcare provider if you have any side effect that bothers you or that does not go away. For more information, ask your healthcare provider or pharmacist.
  • If you have any questions about this information, be sure to discuss them with your doctor. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.

Please see Prescribing Information and Medication Guide for more information about Nplate®.

References:

  1. Buckley MF, James JW, Brown DE, et al. A novel approach to the assessment of variations in the human platelet count. Thromb Haemost. 2000;83:480-484.
  2. Rodeghiero F, Stasi R, Gernsheimer T, et al. Standardization of terminology, definitions and outcome criteria in immune thrombocytopenic purpura of adults and children: report from an international working group. Blood. 2009;113:2386-2393.
  3. Merck Manual Home Edition. Thrombocytopenia. http://www.merckmanuals.com/home/sec14/ch173/ch173d.html?qt=itp&alt=sh. Accessed June 9, 2011.
  4. Cines DB, McMillan R. Management of adult idiopathic thrombocytopenic purpura. Annu Rev Med. 2005;56:425-442.
  5. Cines DB, Blanchette VS. Immune thrombocytopenic purpura. N Engl J Med. 2002;346:995-1008.