Thrombocythemia is a condition caused by high platelet count, which increases your risk of blood clots. If left untreated, these clots can block blood flow to your brain, hands, or feet, causing further health complications. Essential thrombocythemia is a type of blood condition in a category called myeloproliferative neoplasms (MPNs) caused by an overgrowth of megakaryocytes. These specialized cells are found in the bone marrow and are responsible for making platelets.1
Thrombocythemia treatments focus on reducing cells in the bone marrow to limit platelet production, in addition to “thinning” the blood to prevent blood clots. You may, in emergent situations, also undergo treatment to filter out extra platelets from your blood.2
These therapies are used to treat essential thrombocythemia — secondary thrombocythemia (thrombocytosis) typically doesn’t need separate treatments. The symptoms tend to go away once the underlying health condition responsible for increasing platelet levels is addressed. Secondary thrombocythemia is not as dangerous as primary thrombocythemia.
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Treatments for High Platelet Count
Many people living with thrombocythemia don’t know they have it and often don’t experience symptoms. Treatments are typically used only for more severe cases in those who have symptoms from blood clots. Unfortunately, there are no cures for thrombocythemia, but currently available therapies make it possible to live a long, healthy life.
Hydroxyurea for High Platelet Count
Hydroxyurea (Hydrea®, Droxia®) is a chemotherapy drug typically used to treat chronic myelogenous leukemia (cancer of the white blood cells) and some head and neck cancers. It belongs to a class of medications known as antimetabolites, which block cells from making and repairing their DNA. As a result, the cells undergo programmed cell death.3
Hydroxyurea helps reduce the number of cells in the bone marrow, such as megakaryocytes. As a result, your bone marrow produces fewer platelets, lowering your counts to prevent blood clots. Hydroxyurea is available as a tablet or capsule that’s taken once daily with water.
Side effects of this medication include:
- Nausea or vomiting
- Loss of appetite
- Constipation or diarrhea
- Sores in your mouth and throat
- Hair loss
- Changes in your nails and skin
- Skin rashes
- Pale skin
- Weight gain
Long-term use of hydroxyurea may also increase your risk of developing the blood cancer acute myelogenous leukemia (AML). However, thrombocythemia also increases your risk of AML, so doctors and researchers are working to determine hydroxyurea’s impact.1
Aspirin for High Platelet Count
Aspirin® is a well-known preventative treatment for blood clots and heart attacks.4 Doctors prescribe Aspirin® to thrombocythemia patients due to its blood-thinning effects. Specifically, it stops platelets from sticking together, preventing blood clots from forming. Aspirin® is taken once daily at a dose of 75 to 100 milligrams (mg).5 In severe cases of thrombocythemia, Aspirin® is given in addition to hydroxyurea to lower your blood clot risk.
Side effects of Aspirin® therapy include:6
- Nausea or vomiting
- Stomach pain
While Aspirin® is an effective thrombocythemia treatment, it can increase your risk of bleeding. Don’t begin aspirin therapy without talking to your doctor first. This is because Aspirin® interacts with several other medications and herbal supplements, which may lead to dangerous bleeding if taken together. Contact your doctor immediately if you begin to vomit blood or a substance that looks like coffee grounds or if there is blood in your stools.
Anagrelide for High Platelet Count
Anagrelide (Agrylin®) is a platelet-reducing agent prescribed for treating thrombocythemia and other MPNs. This medication stops megakaryocytes from maturing, preventing them from making platelets. As a result, your platelet levels gradually decrease to normal levels. Anagrelide is taken as a capsule two or four times a day.7
Anagrelide isn’t associated with an increased risk of AML — however, it does have some undesirable side effects, making it a difficult medication to tolerate. With this, doctors may only prescribe it to people who don’t improve on hydroxyurea.
Side effects of anagrelide include:8
- Fluid retention (edema), which can cause swelling of your legs, feet, arms, hands, and face
- Abnormal heart rhythm (arrhythmias) or pounding heart rate (palpitations)
- Heart failure
- Rapid weight gain
- Dry or sore throat
- Body aches
- Difficulty breathing
- Chest pain
- “Pins and needles,” tingling, or burning sensations
Interferon Alfa for High Platelet Count
Interferon alfa (Intron® A, Roferon®-A) is an antiviral drug typically used to treat hepatitis (liver inflammation) caused by viral infections, in addition to certain types of cancer. It also blocks the growth of immature megakaryocytes to help reduce platelet count in people with thrombocythemia. Interferon alfa-2a and interferon alfa-2b are given as injections.9,10
Side effects of interferon alfa include:
- Irritation, bleeding, bruising, pain, or swelling at the injection site
- Hair loss
- Taste changes
- Dry mouth
- Trouble concentrating
- Muscle pain
- Weight changes
- Feeling too hot or too cold
Other Drugs to Treat Thrombocythemia
There are additional interventions used in the treatment of thrombocythemia, including:
- Ruxolitinib (Jakavi®) — a Janus kinase (JAK) inhibitor that blocks cell growth signals in MPNs13
- Ropeginterferon (Bestremi®)
- Fedratinib (Inrebic®) and Pacritinib (Vonjo®) used for myelofobrosis
Plateletpheresis for Very High Platelet Count
Thrombocythemia can also be treated with plateletpheresis. Also known as platelet reduction apheresis, this procedure removes extra platelets from your blood and returns your filtered blood to you.11
During plateletpheresis, you’ll have a needle inserted into a vein in each of your arms. One needle removes your blood, which then runs into a machine that isolates the platelets and puts them in a separate bag. The rest of your blood contains red blood cells, white blood cells, and other proteins, which are returned to your body through the other needle. Overall, the procedure takes around 90 minutes.12
The Future of Thrombocythemia Treatments
Doctors and researchers continue to learn more about thrombocythemia and how to treat it every year. Before these therapies can be used for the general public, they must first undergo clinical trials to ensure they’re safe and effective. There are several studies currently recruiting thrombocythemia patients who are newly diagnosed or who have been living with the condition for some time.
Clinical trials are an option for those looking to try new treatments or for those interested in helping to advance science.