Mepolizumab Injection
Mepolizumab injection (Nucala) is a biologic medication used to treat severe asthma, chronic rhinosinusitis with nasal polyps, COPD, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic syndrome in eligible adults and children.
🧬 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 →
📖 Mepolizumab Injection: Patient Information Guide
A plain-language walkthrough of Mepolizumab 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▾
Mepolizumab injection (Nucala) is a biologic approved for several conditions that involve elevated eosinophils or eosinophil-driven inflammation.
- Severe asthma: Nucala is an add-on maintenance treatment for patients aged 6 and older with severe asthma and an eosinophilic phenotype (high eosinophil levels in the blood or airways)
- Chronic rhinosinusitis with nasal polyps (CRSwNP): Nucala is an add-on maintenance treatment for adults 18 and older whose nasal polyps aren't adequately controlled with nasal corticosteroids
- COPD (chronic obstructive pulmonary disease): Nucala is an add-on maintenance treatment for adults with inadequately controlled COPD and an eosinophilic phenotype
- Eosinophilic granulomatosis with polyangiitis (EGPA): Nucala treats this rare inflammatory blood vessel condition in adults
- Hypereosinophilic syndrome (HES): Nucala treats adults and adolescents 12 and older who have had HES for 6 months or more without an identifiable non-blood-related cause
- Not for acute attacks: Nucala is not used to relieve sudden asthma attacks, acute bronchospasm, or status asthmaticus
⚙️How it works▾
Mepolizumab is a monoclonal antibody — a lab-made protein that acts like a very targeted interceptor. It binds to interleukin-5 (IL-5), a signaling protein (cytokine) that tells the body to grow, activate, and sustain eosinophils (a type of infection-fighting white blood cell). In conditions like severe asthma, EGPA, and HES, too many eosinophils build up and cause harmful inflammation. By blocking IL-5 from attaching to eosinophil receptors, mepolizumab reduces the production and survival of these cells, which helps calm the inflammation at the root of these conditions.
Blood eosinophil levels typically begin to fall within 4 weeks of the first dose and stay reduced as long as treatment continues. The exact way this translates into clinical benefit for each condition has not been definitively established.
💊How it's taken▾
Nucala is given as a subcutaneous injection (a shot under the skin) once every 4 weeks. The injection is given into the upper arm, thigh, or abdomen. The dose and number of injections per visit vary by condition and age, so always follow your prescriber's specific instructions. Food and drink do not affect this medication.
- For severe asthma in children 6–11 years, Nucala must be given by a healthcare provider or trained caregiver
- For adults and adolescents 12 and older, the prefilled autoinjector or prefilled syringe may be used for self-injection at home after training from your healthcare provider
- For EGPA and HES, each dose is given as 3 separate injections, each at least 2 inches apart
- If you miss a dose, take it as soon as you remember and then return to your regular schedule
🤒Side effects — in detail▾
The most common side effects of Nucala differ slightly by condition, but generally include:
- Headache
- Injection site reactions (redness, pain, or swelling at the injection spot)
- Back pain
- Fatigue
- Throat pain (oropharyngeal pain)
- Joint pain (arthralgia)
- Diarrhea
- Cough
Serious reactions to watch for include signs of a severe allergic reaction (hives, throat swelling, trouble breathing, low blood pressure) and shingles (a painful, blistering rash). Seek emergency care or call your doctor right away if any of these occur.
⚠️Warnings & precautions▾
- Serious allergic reactions (hypersensitivity): Reactions including anaphylaxis, severe swelling (angioedema), low blood pressure, and hives have been reported — sometimes hours or even days after the injection. If this happens, Nucala must be stopped and emergency care sought immediately.
- Not for acute attacks: Nucala will not work fast enough to treat a sudden asthma attack or acute COPD flare. Always have a rescue inhaler available for emergencies.
- Shingles (herpes zoster): Cases of shingles have occurred in patients taking Nucala. Ask your doctor whether you should get the shingles vaccine before starting treatment.
- Stopping steroids too quickly: If you take corticosteroid medications, do not stop them suddenly when starting Nucala. Any steroid reduction must be done slowly and under a doctor's supervision to avoid withdrawal effects or unmasking of other conditions.
- Parasitic infections: Eosinophils help the body fight certain parasitic (worm) infections. Pre-existing parasitic infections should be treated before starting Nucala. If you develop one during treatment that doesn't respond to treatment, Nucala may need to be paused.
🔀What it interacts with▾
Formal drug interaction studies have not been conducted with mepolizumab, so specific interaction data are limited. That said, there are important considerations to discuss with your doctor:
- Corticosteroids (steroids): Do not stop oral or inhaled steroids abruptly when starting Nucala — the dose should be reduced gradually under medical supervision to avoid withdrawal
- Other biologic medications: No formal data are available, but always tell your doctor and pharmacist about all medications, supplements, and biologics you are taking
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▾
- Allergy to mepolizumab or its ingredients: Nucala is contraindicated if you have ever had a serious allergic reaction to mepolizumab or any component of the formulation
- Pregnancy: Human data are limited. Mepolizumab can cross the placenta, particularly in the second and third trimesters. Tell your doctor if you are pregnant or planning to become pregnant
- Breastfeeding: It is unknown whether mepolizumab passes into human breast milk. Discuss the benefits and risks with your doctor
- Active parasitic (worm) infection: Should be treated and resolved before starting Nucala
- Shingles vaccination status: Ask your doctor whether you should be vaccinated before starting Nucala
- Children under 6: Nucala has not been established as safe or effective for asthma in children under 6, or for any of its other approved uses in children under 12 (HES) or under 18 (CRSwNP, COPD, EGPA)
- Older adults (65+): No meaningful differences in safety or effectiveness were observed in older patients compared to younger patients, but individual sensitivity is possible
🚑If you take too much▾
There is no specific antidote if too much mepolizumab is taken. If an overdose occurs, treatment is supportive — meaning healthcare providers will monitor you and manage any symptoms that arise. Contact the Poison Help line at 1-800-222-1222 or seek emergency care for guidance.
📡Pharmacodynamics — effects in the body▾
Mepolizumab's most measurable effect is a significant reduction in blood eosinophil counts. This reduction begins within 4 weeks of the first dose and is maintained throughout the treatment period. The magnitude of reduction is substantial across all approved conditions — for example, in severe asthma trials, blood eosinophils dropped by around 84% compared to placebo. Similar reductions were seen in patients with CRSwNP, COPD, EGPA, and HES. Because eosinophils drive the inflammation in these conditions, reducing their numbers is the key mechanism through which the drug works.
🔬Pharmacokinetics — how your body processes it▾
After a subcutaneous injection, mepolizumab is about 80% absorbed into the bloodstream. With repeated dosing every 4 weeks, drug levels in the body build up to approximately twice the initial exposure at steady state. The drug has a half-life of 16 to 22 days, meaning it stays active in the body for several weeks after each dose. Mepolizumab is broken down by proteolytic enzymes (proteins that digest other proteins) found throughout the body — it is not primarily processed by the liver. Age, sex, and race do not significantly affect how the body clears the drug.
📦How to store it▾
Store vials below 77°F (25°C). Do not freeze. Store in the original carton to protect from light.
📄 Written from Mepolizumab 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 Mepolizumab Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What is Nucala actually doing for my asthma — is it like an inhaler? ▾
Can I inject Nucala at home myself, or do I have to go to a clinic every month? ▾
What side effects should I actually watch out for? ▾
I take a steroid pill every day for my condition — do I stop it now that I'm starting Nucala? ▾
Is it safe to take Nucala if I'm pregnant or trying to get pregnant? ▾
What happens if I miss a dose? ▾
Is Mepolizumab Injection available over the counter? ▾
When was Mepolizumab Injection first available? ▾
💬 Answers drafted from Mepolizumab 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 Mepolizumab Injection comes
Mepolizumab 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
- Nucala is used as add-on maintenance treatment for severe asthma in patients 6 years and older with an eosinophilic phenotype
- Nucala is used as add-on maintenance treatment for chronic rhinosinusitis with nasal polyps (CRSwNP) in adults 18 and older
- Nucala is used as add-on maintenance treatment for COPD in adults with an eosinophilic phenotype
- Nucala is used to treat eosinophilic granulomatosis with polyangiitis (EGPA) and hypereosinophilic syndrome (HES) in eligible adults and adolescents
- Nucala is given as a subcutaneous (under the skin) injection into the upper arm, thigh, or abdomen once every 4 weeks
- Nucala vials must be reconstituted and administered by a healthcare professional; the prefilled autoinjector and 100 mg prefilled syringe can be self-injected by adults and adolescents 12 and older after proper training
- Nucala prefilled autoinjector and prefilled syringe should be removed from the refrigerator and allowed to sit at room temperature for 30 minutes before use — do not warm in any other way
- Never inject into skin that is tender, bruised, red, or hard; if a dose is missed, give it as soon as possible and then resume the usual schedule
📊 Mepolizumab Injection across the U.S. market
How Mepolizumab 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.
📈 How widely Mepolizumab Injection is used
A general measure of how commonly Mepolizumab 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 Mepolizumab 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 Mepolizumab Injection prescribed? Of the 1,596 medications we measure, Mepolizumab Injection ranks #703 by Medicaid prescriptions — more than 56% of them.
Utilization by Mepolizumab 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.
1 ML mepolizumab 100 MG/ML Auto-Injector Most dispensed
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2170990
mepolizumab 100 MG Injection
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1720601
1 ML mepolizumab 100 MG/ML Prefilled Syringe
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2173820
0.4 ML mepolizumab 100 MG/ML Prefilled Syringe
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2596444
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 Mepolizumab 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 4 of 6 listed Mepolizumab Injection NDCs with Medicaid activity.
🔍 Compare Mepolizumab Injection products
A representative set of FDA-listed product records for Mepolizumab 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 | ||||
| 40 mg/0.4 mL | Subcutaneous | GlaxoSmithKline LLC × 3 listings | BLA | View NDC → |
| 100 mg/mL | Subcutaneous | GlaxoSmithKline LLC × 6 listings | BLA | View NDC → |
Showing 9 of 9 products — FDA National Drug Code Directory. See every product, package size and price: browse all 9 Mepolizumab 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 Mepolizumab 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 Mepolizumab 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 Mepolizumab 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 1720597 3 dose forms · 4 strengths
-
Dose form (SCDF) Auto-Injector RxCUI 2170989In current FDA listingsClinical drug / strength (SCD) 1 ML mepolizumab 100 MG/MLRxCUI 2170990 -
Dose form (SCDF) Injection RxCUI 1720600In current FDA listingsClinical drug / strength (SCD) 100 MGRxCUI 1720601 -
Dose form (SCDF) Prefilled Syringe RxCUI 2173819No current FDA listingClinical drug / strength (SCD) 0.4 ML mepolizumab 100 MG/MLRxCUI 25964441 ML mepolizumab 100 MG/MLRxCUI 2173820
Look up RxCUI 1720597 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 Mepolizumab 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
Mepolizumab Injection belongs to the Interleukin-5 Antagonist 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. GlaxoSmithKline LLC 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.