Promacta and Its Role in Treating Low Platelet Levels

If you’re suffering from a particular medical condition that causes a low level of platelet cells in your blood (thrombocytopenia), your doctor might recommend Promacta. This article will review how this drug works and cover the benefits and side effects.

What Is Promacta?

Promacta, also known by its generic name eltrombopag, is a medication that is typically prescribed to treat low platelet levels in patients with chronic immune thrombocytopenia (特发性血小板减少症), severe aplastic anemia, and hepatitis C virus (HCV)-related thrombocytopenia. This medication is often used as a second-line treatment option when other medications have failed to manage a patient’s platelet levels effectively.

Promacta belongs to the “platelets stimulating agent” drug class that works by stimulating cells to produce platelets in the body, which are crucial for blood clotting and preventing excessive bleeding. 

This medication can only be obtained via a doctor’s prescription and is available in tablet and oral suspension forms taken once a day.

Is There a Generic for Promacta?

No, there is no generic version. It is only available in a branded form, which makes this medication expensive, even with insurance.  

What Is Promacta Used To Treat?

Promacta has been approved for treating thrombocytopenia in patients (adults and pediatric age 1 year and older) suffering from chronic immune thrombocytopenic purpura (ITP) when other treatments (splenectomy) or medicines (corticosteroid, 免疫球蛋白) do not work well enough. 

Promacta is also indicated to treat thrombocytopenia in patients with chronic hepatitis C (CHC). In these patients, whose low platelet count prevents them from initiating or continuing interferon-based therapy, Promacta is used to initiate and maintain the interferon treatment. Besides treating thrombocytopenia, it is also used alone or in combination with immunosuppressive therapy to treat severe aplastic anemia in adult patients and children aged 2 and older. 

它是如何工作的？

Promacta works to promote platelet production in your body. It contains an active substance called eltrombopag, a form of small non-peptide molecule that binds to the natural protein receptor thrombopoietin receptor (TPO-R). 

Mode of Action

Eltrombopag acts as a thrombopoietin receptor agonist (TPO-RA) and works by binding to and activating the natural thrombopoietin (TPO) receptor, a protein found on the surface of platelet precursor cells such as megakaryocytes. Megakaryocytes are large cells that are found in the bone marrow and are responsible for producing and releasing platelets into the bloodstream.

When a thrombopoietin receptor agonist activates the natural TPO receptor, it signals the growth and maturation of the megakaryocytes in the bone marrow to produce more platelets and release them into the bloodstream. This results in an increase in the number of circulating platelets in the blood, which can help prevent bleeding and bruising in individuals with low platelet counts.

How Long Does Promacta Take To Work?

According to reports of clinical studies conducted on adults with chronic ITP, Promacta treatment increases platelet counts within a week. The earliest maximum response was observed after 2 weeks of therapy. In the two main studies conducted, 54% of patients reached their platelet goal of ≥50,000/mcl in one study and 88% reached their goal of ≥50,000/mcl in the other study, within a month and a half. By completion of the first year of clinical studies, 80% of patients reported less fatigue and less bleeding or bruising.  

Promacta Dosage Form and Strength

Promacta is available in two forms with different strengths, which include:

• Tablets with the strength of 12.5 mg, 25 mg, 50 mg, and 75 mg 
• Oral suspension with 12.5 mg or 25 mg powder for reconstitution

剂量信息

The dose of Promacta will depend on your platelet count and your medical conditions. In general, the starting dose of Promacta in adult and pediatric patients is as follows:

For Adult and Pediatric Patients (6 Years and Older) With ITP

The recommended starting dose for Promacta in adults and pediatrics (6 years and older) with chronic ITP is 50 mg once daily. 

• For pediatric patients who are aged less than 6 years, the starting dose is 25 mg once a day. 
• Patients with ITP and liver problems or certain Asian ancestries should receive Promacta at a lower dose of 25 mg once per day. 

Your doctor may adjust your dose based on your response to the medication and platelet count, but the maximum recommended dose should not exceed 75 mg/day. 

For Adults with Chronic Hepatitis C (CHC)

The initial dose of Promacta for patients with CHC is 25 mg once a day. Moreover, it is advised to use the smallest effective dose of Promacta to reach and sustain the platelet level required to begin and continue interferon-based treatment.

The maintenance dose of Promacta should not be more than 100 mg/day.

For Patients with Severe Aplastic Anemia

For patients using Promacta in combination with immunosuppressants:

• For patients 12 years and older the daily dose is 150 mg once daily. 
• For patients between the ages of 6-11 years old the daily dose is 75 mg once daily.
• For children between the ages of 2-5 years old the dose is 2.5 mg/kg. 

For patients using Promacta alone after an insufficient response to immunosuppressants, the dose is 50 mg once daily.

Patients with certain Asian ancestries or those with liver impairment may need their dose adjusted. Additionally, your dose of Promacta may be adjusted based on your body’s response to the medication. The recommended maximum maintenance dose is 150 mg once daily.

How Is Promacta Taken?

The Promacta tablets or suspension mixture is taken orally (by mouth). 

If you are taking calcium-rich foods (such as dairy products and calcium-fortified juices), medications (e.g., antacids), or any other supplements containing iron, calcium, aluminum, magnesium, selenium, and zinc, take Promacta either 2 hours before or 4 hours after the medication, food or supplements. 

Tablets should be swallowed whole; do not crush and mix them with other foods or liquids.

The oral suspension powder of Promacta should only be prepared with water. A new single-dose oral syringe should be used with each dose of Promacta. Do not reuse the oral dosing syringe.

Is Promacta a Form of Chemotherapy?

No, Promacta is not a form of chemotherapy but a prescription medicine typically prescribed to treat thrombocytopenia in patients with ITP and CHC and treat severe aplastic anemia. 

Possible Side Effects

The side effects of Promacta may vary among patients and the condition they are suffering from. For example, the most frequent undesirable effects observed in adult patients with ITP are: 

• Nausea and Vomiting
• Myalgia (muscles pain)
• 腹泻
• 上呼吸道感染
• Urinary tract infections
• 头痛
• Abnormal liver tests

Common Side Effects In Pediatric Patients With ITP 

The most commonly reported side effects in pediatric patients (aged 1 year or older) are upper respiratory tract infections and nasopharyngitis (cold symptoms).

Common Side Effects in Patients With CHC 

Patients with chronic hepatitis C-associated thrombocytopenia may experience the following symptoms: 

• Anemia (low red blood cell count)
• 发烧
• 发冷
• Alopecia (hair loss)
• 瘙痒
• Peripheral edema (swelling of the lower limbs)
• Myalgia (muscles pain)
• Headache, fatigue, and nausea
• 腹泻 
• Low appetite
• Influenza-like illness and cough
• Trouble sleeping (insomnia)

Common Side Effects in Patients With Severe Aplastic Anemia

Patients with severe aplastic anemia may experience:

• Abnormal liver tests
• 皮疹
• Hyperpigmentation of the skin  

Promacta Precautions

If you are taking Promacta, there are several precautions that you should keep in mind to ensure your safety and well-being. Promacta may not be suitable for you if:

• You are pregnant or intend to become pregnant, as Promacta may harm an unborn baby. It is recommended to use effective birth control while taking Promacta and for at least 7 days after stopping the medication.
• You are breastfeeding or planning to breastfeed, as the study on the secretion of Promacta in human breast milk is limited. Therefore, breastfeeding is not recommended during this treatment.
• You have an allergy to any component of Promacta.
• You have myelodysplastic syndrome (MDS) (a type of blood cancer).
• You have liver problems and bleeding problems.
• You have had a history of cataracts. New or worsened cataracts have been reported in people taking Promacta.
• You have received a splenectomy (surgery to remove the spleen). 
• You are taking multivitamins, mineral supplements, or blood thinners and antacids.

Overall, it is important to follow your doctor’s instructions carefully while taking Promacta and to report any unusual symptoms or side effects immediately.

Promacta Cost 

The cost of Promacta can vary depending on the medication form and strengths. The average wholesale price (AWP) for a 30-day supply of Promacta tablets is as follows:

• Promacta 12.5 mg costs approximately $7,074.97 for a supply of 30 tablets. 
• Promacta 25 mg tablets have an AWP of approximately $6,035.45 for a supply of 30 tablets. 
• Promacta 50 mg costs about $5,976.42 for a supply of 14 tablets.
• Promacta 75 mg costs about $16,382.51 for a supply of 30 tablets. 

Cost of Promacta Oral Suspension:

The AWP for a 30-day Promacta oral suspension supply (12.5 mg/5 ml or 25 mg/5 ml) ranges from approximately $7,074.97 to 7,075.35, depending on the dosage.