Romiplostim Injection
Romiplostim is an injectable medication that boosts platelet production, used to treat low platelet counts in immune thrombocytopenia (ITP) and to improve survival after life-threatening radiation exposure.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
📖 Romiplostim Injection: Patient Information Guide
A plain-language walkthrough of Romiplostim Injection — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Romiplostim (Nplate injection) is approved for two distinct situations involving dangerously low platelet counts:
- Immune thrombocytopenia (ITP) in adults: Nplate treats low platelets caused by the immune system when previous treatments — including corticosteroids, immunoglobulins, or spleen removal — have not worked well enough.
- ITP in children (1 year and older): Nplate treats ITP in pediatric patients who have had the condition for at least 6 months and have not responded sufficiently to standard therapies.
- Hematopoietic Syndrome of Acute Radiation Syndrome (HS-ARS): Nplate is used to increase survival in adults and children — including newborns — who have been exposed to radiation doses high enough to suppress bone marrow function.
- Important limits: Nplate is not approved for low platelets caused by myelodysplastic syndrome (MDS) or any other cause besides ITP. It should only be used when low platelet counts increase bleeding risk — not to normalize counts.
⚙️How it works▾
Romiplostim works by binding to and switching on the body's thrombopoietin (TPO) receptor — the same receptor that the body's own platelet-stimulating protein, thrombopoietin, targets. Activating this receptor signals the bone marrow to ramp up platelet production. This leads to a higher platelet count in the blood, which helps protect against abnormal bleeding. The effect mimics what the body would naturally do if it were producing enough thrombopoietin on its own.
Because the drug is cleared partly through the TPO receptors on platelets themselves, patients with very low platelet counts may have higher drug levels in the blood, while those with higher counts may have lower levels. This is why dose adjustments based on platelet count monitoring are so important.
💊How it's taken▾
Nplate is given as a subcutaneous (under the skin) injection — never by mouth or intravenously. For ITP, it is injected once a week, and the dose is carefully adjusted based on how your platelet count responds. Your doctor will check your blood counts weekly during dose adjustments, then monthly once the dose is stable.
- For radiation exposure (HS-ARS), Nplate is given as a single injection as soon as possible after exposure — no weekly schedule is used in this setting.
- The injection volume can be very small, so a specially calibrated syringe (with 0.01 mL markings) is required for accurate dosing.
- Always follow your prescriber's instructions on dose and timing — do not adjust on your own.
🤒Side effects — in detail▾
The most commonly reported side effects with Nplate include:
- Joint pain (arthralgia) and muscle pain (myalgia)
- Headache
- Dizziness
- Trouble sleeping (insomnia)
- Stomach or abdominal pain
- Pain in the arms or legs
- Tingling or numbness (paresthesia)
- In children: bruising (contusion), upper respiratory infections, and sore throat (oropharyngeal pain) are very common
More serious reactions — including blood clots, signs of bone marrow changes, or a loss of drug response over time — require prompt medical attention. If you notice sudden leg swelling, chest pain, or shortness of breath, seek emergency care right away.
⚠️Warnings & precautions▾
- Blood clots: Nplate can cause platelet counts to rise too high, leading to dangerous clots in veins or arteries — including in the legs, lungs, heart, brain, and the portal vein in the liver. This risk exists even at platelet counts that don't look alarming. Nplate should never be used to push platelet counts to a normal level.
- Risk of leukemia in MDS patients: Nplate must not be used for low platelets caused by myelodysplastic syndrome (MDS). In MDS patients, Nplate has been associated with an increased risk of progression to acute myelogenous leukemia (AML), a serious blood cancer.
- Bone marrow fibrosis: Long-term use may cause increased reticulin fiber or collagen formation in the bone marrow. This has been seen in both adults and children on extended therapy. Your doctor may monitor for this over time.
- Loss of response: If the drug stops working — for example, if your platelet counts no longer respond — the cause may be antibodies forming against romiplostim. Nplate will be discontinued if counts don't improve after 4 weeks at the maximum dose.
- Rebound low platelets after stopping: Blood counts should be monitored weekly for at least 2 weeks after stopping Nplate, as platelet counts may drop significantly.
🔀What it interacts with▾
Nplate has limited known drug interactions, but it is often used alongside other ITP medications — your doctor should know everything you take:
- Corticosteroids, danazol, azathioprine, IVIG, and anti-D immunoglobulin: Nplate can be used with these standard ITP treatments, but platelet counts must be monitored closely to avoid levels that become too high and increase clot risk.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- MDS (myelodysplastic syndrome): Nplate is not approved for this condition and may increase the risk of progression to blood cancer — do not use it for MDS-related low platelet counts.
- Chronic liver disease: Portal vein thrombosis (a blood clot in the liver's main vein) has been reported in patients with and without liver disease — tell your doctor about any liver conditions.
- Pregnancy: Nplate may harm an unborn baby based on animal studies. Tell your doctor immediately if you are pregnant or become pregnant during treatment.
- Breastfeeding: Women should not breastfeed while using Nplate due to the potential for serious harm to the nursing infant.
- Children under 1 year: Safety and effectiveness in children under 1 year of age with ITP have not been established.
- Older adults (65+): No major differences in safety have been found compared with younger patients, but dose adjustments should be made carefully given the higher chance of other health issues or medications.
🚑If you take too much▾
If too much Nplate is given, platelet counts can rise excessively, which significantly increases the risk of dangerous blood clots. In that situation, Nplate would be stopped and platelet counts monitored closely. Treatment can be restarted later at an adjusted dose once counts return to a safe level — always following the prescribed dosing guidelines.
📡Pharmacodynamics — effects in the body▾
Nplate produces dose-related increases in platelet counts. In patients with ITP, a single subcutaneous dose led to peak platelet counts 1.3 to nearly 15 times higher than baseline over a 2- to 3-week period. With repeated weekly dosing, most patients were able to reach and maintain platelet counts above the level needed to reduce bleeding risk. In the radiation exposure setting, a single dose is expected to meaningfully reduce the severity and duration of dangerously low platelet counts caused by bone marrow suppression.
🔬Pharmacokinetics — how your body processes it▾
After a subcutaneous injection, romiplostim reaches peak blood levels roughly 7 to 50 hours after dosing (typically around 14 hours). Its half-life — the time for the body to clear half the drug — ranges widely from 1 to 34 days, with a median of about 3.5 days. Interestingly, how quickly the drug is cleared depends partly on how many platelets are in the blood: patients with very low platelets tend to have higher drug levels, while those with higher platelet counts clear it faster. Drug levels vary considerably from person to person and do not track linearly with the dose given. In children with ITP, blood levels fall within the same range seen in adults at similar doses, though variability is also high.
📦How to store it▾
Store Nplate vials in the refrigerator at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light. Do not freeze. stored in the original carton at room temperature up to a maximum of 25°C (77°F) for a single period of up to 30 days.
📄 Written from Romiplostim Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Romiplostim Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is Nplate doing in my body? ▾
How often will I need to get these injections? ▾
What side effects should I actually watch out for? ▾
Can I take my other ITP medications while using Nplate? ▾
Is Nplate safe to use if I'm pregnant or trying to get pregnant? ▾
What happens if I stop taking Nplate? ▾
Is Romiplostim Injection available over the counter? ▾
When was Romiplostim Injection first available? ▾
Who makes Romiplostim Injection? ▾
💬 Answers drafted from Romiplostim Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Romiplostim Injection comes
Romiplostim Injection is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Injection
How this form is used
- Nplate is used to treat immune thrombocytopenia (ITP) in adults and children 1 year and older who have not responded well to corticosteroids, immunoglobulins, or splenectomy
- Nplate is used to increase survival in adults and children (including newborns) exposed to life-threatening, bone-marrow-suppressing doses of radiation (HS-ARS)
- Nplate is given as a subcutaneous (under the skin) injection — never by any other route
- For ITP, Nplate is injected once weekly; for radiation exposure, a single injection is given as soon as possible after exposure
- Nplate comes as a powder in single-dose vials that must be reconstituted (mixed) with Sterile Water for Injection before use — do not shake the vial, gently swirl instead
- Nplate must be administered using a syringe with 0.01 mL graduations to ensure accurate dosing; discard any unused portion and never pool leftover amounts from multiple vials
📊 Romiplostim Injection across the U.S. market
How Romiplostim Injection appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
📈 How widely Romiplostim Injection is used
A general measure of how commonly Romiplostim Injection is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Romiplostim Injection is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Romiplostim Injection prescribed? Of the 1,596 medications we measure, Romiplostim Injection ranks #802 by Medicaid prescriptions — more than 50% of them.
Utilization by Romiplostim Injection product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
romiplostim 0.125 MG Injection Most dispensed
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2201538
romiplostim 0.25 MG Injection
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1728092
romiplostim 0.5 MG Injection
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1728097
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Romiplostim Injection, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 3 of 6 listed Romiplostim Injection NDCs with Medicaid activity.
🔍 Compare Romiplostim Injection products
A representative set of FDA-listed product records for Romiplostim Injection — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 125 mcg/0.25 mL | Subcutaneous | Amgen, Inc × 2 listings | BLA | View NDC → |
| 250 mcg/0.5 mL | Subcutaneous | Amgen, Inc × 2 listings | BLA | View NDC → |
| 500 mcg/mL | Subcutaneous | Amgen, Inc × 2 listings | BLA | View NDC → |
| 125 mcg/0.25 mL | Subcutaneous | Amgen Inc | BLA | View NDC → |
| 250 mcg/0.5 mL | Subcutaneous | Amgen Inc | BLA | View NDC → |
| 500 mcg/mL | Subcutaneous | Amgen Inc | BLA | View NDC → |
| 125 mcg/0.25 mL | — | Patheon Italia S.p.A. | DRUG FOR FURTHER PROCESSING | View NDC → |
| 0.4 mg | — | Patheon Italia S.p.A. | DRUG FOR FURTHER PROCESSING | View NDC → |
| 0.6 mg | — | Patheon Italia S.p.A. | DRUG FOR FURTHER PROCESSING | View NDC → |
Showing 12 of 12 products — FDA National Drug Code Directory. See every product, package size and price: browse all 12 Romiplostim Injection NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Romiplostim Injection — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Romiplostim Injection in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Romiplostim Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 805452 1 dose form · 3 strengths
-
Dose form (SCDF) Injection RxCUI 1728091In current FDA listings
Look up RxCUI 805452 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Romiplostim Injection is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Romiplostim Injection belongs to the Thrombopoietin Receptor Agonist class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Amgen Inc is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.