Romiplostim
Also known as Nplate
Romiplostim is a thrombopoietin (TPO) receptor agonist engineered as a peptibody, combining peptide sequences that activate the TPO receptor with an antibody Fc fragment that extends its circulating half-life. It is approved for chronic immune thrombocytopenia (ITP) in adults and children who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. It is given as a once-weekly subcutaneous injection, typically administered and monitored by a healthcare professional based on regular platelet counts. It is a prescription-only biologic therapy requiring individualized, weight-based dosing.
Reported benefits
- Increases and sustains platelet counts in chronic ITP resistant to first-line therapy
- Reduces the need for rescue therapies (corticosteroids, immunoglobulins) in responders
- Once-weekly dosing schedule
- Approved for use in both adults and children
How it works
Romiplostim binds and activates the thrombopoietin receptor (MPL) on megakaryocytes and their progenitors, mimicking the action of endogenous thrombopoietin. This stimulates megakaryocyte proliferation and maturation, ultimately increasing platelet production and release from the bone marrow. Because it does not share sequence homology with native thrombopoietin, it was designed to avoid triggering antibodies that cross-react with the endogenous hormone.
Dosing ranges
| Tier | Dose | Frequency |
|---|---|---|
| Low | 1 mcg | once weekly, subcutaneous, dosed per kg body weight (starting dose) |
| Moderate | 3 mcg | once weekly, subcutaneous, dosed per kg body weight (typical titrated dose) |
| High | 10 mcg | once weekly, subcutaneous, dosed per kg body weight (maximum recommended dose) |
Estimate your dose
Dose estimator
Educational estimate for Romiplostim, scaled to body size. Not medical advice.
Read before using
This tool produces a rough, educational estimate by scaling commonly-published research ranges to lean body mass. It is not a prescription, medical advice, or a substitute for a licensed clinician. Most peptides use fixed dosing, not weight-based dosing. Individual needs vary. You are solely responsible for how you use this information.
Mixing & syringe units
Target dose follows the estimate above. Change it there, or edit it directly below.
Reconstitution calculator
How much water to add and how many insulin-syringe units to draw for Romiplostim. Educational only.
Draw to this mark
0.1units
= 0.001 mL for a 3 mcg dose
Concentration
5,000 mcg/mL
Doses per vial
3,333
Under 2 units is hard to measure accurately. Use less water for a larger, easier-to-read draw.
A U-100 syringe reads 100 units per mL. This is a reconstitution math helper only, not a prescription or dosing advice. Verify every calculation and consult a qualified healthcare provider.
Possible side effects
Stacking notes
Used as monotherapy for chronic ITP in most regimens; sometimes combined with corticosteroids or other ITP therapies under hematology supervision.
Common protocols
Common questions
What is Romiplostim used for?
Romiplostim is a thrombopoietin (TPO) receptor agonist engineered as a peptibody, combining peptide sequences that activate the TPO receptor with an antibody Fc fragment that extends its circulating half-life. It is approved for chronic immune thrombocytopenia (ITP) in adults and children who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. It is given as a once-weekly subcutaneous injection, typically administered and monitored by a healthcare professional based on regular platelet counts. It is a prescription-only biologic therapy requiring individualized, weight-based dosing. Reported benefits include increases and sustains platelet counts in chronic itp resistant to first-line therapy, reduces the need for rescue therapies (corticosteroids, immunoglobulins) in responders, once-weekly dosing schedule.
What is a typical Romiplostim dose?
Reported ranges run 1-10 mcg. A low protocol is 1 mcg once weekly, subcutaneous, dosed per kg body weight (starting dose), and a high protocol is 10 mcg once weekly, subcutaneous, dosed per kg body weight (maximum recommended dose). This is reference information, not a dosing recommendation.
What is the half life of Romiplostim?
Highly variable between patients, generally reported in a range of about 1 to 34 days. That is what sets the dosing frequency, and it is why the timing guidance is weekly · clinician-directed.
How is Romiplostim administered?
Subcutaneous: into fat, under the skin. Subcutaneous injection prepared and typically administered by a healthcare professional based on weekly platelet counts.
How long is a Romiplostim cycle?
Continuous once-weekly dosing while platelet response is maintained, with dose titrated by 1 mcg/kg increments based on platelet counts on, followed by Discontinued if no adequate platelet response is achieved after dose escalation to the maximum recommended dose over about four weeks off.
What are the side effects of Romiplostim?
Reported side effects include headache, fatigue, and arthralgia, risk of thromboembolic events with excessive platelet elevation, bone marrow reticulin fibrosis with prolonged use, monitored periodically, worsening of thrombocytopenia after discontinuation (rebound) in some patients, increased risk of hematologic malignancy progression in patients with myelodysplastic syndromes (contraindicated in that population). Evidence level for this compound is well studied.
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Educational use only, not medical advice. This profile is provided for research and educational purposes. Romiplostim may be a research compound or a prescription medication; nothing here is intended to diagnose, treat, cure, or prevent any disease. Dosing figures reflect commonly-published research ranges, not a prescription. Consult a qualified healthcare provider before making any health decision. Read the full disclaimer →