[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Biologics for asthma](https://durgical.com/en/pharmacology/classes/biologics-for-asthma/) › Mepolizumab

# Mepolizumab

## Biologics for asthma?

Biologics for asthma

An anti-IL-5 antibody that lowers eosinophils, used in severe eosinophilic asthma, COPD, nasal polyps, EGPA and hypereosinophilic syndrome.

Updated Nov 1, 2026

## Quick facts

**Group**
[Biologics for asthma](https://durgical.com/en/pharmacology/classes/biologics-for-asthma/)

**Target**
Interleukin-5 (IL-5)

**Used for**
Severe eosinophilic asthma

**Key effects**
Injection-site pain · Headache · Dry

**Monitor**
Blood eosinophil count · Exacerbations

**ATC**
R03DX09

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Mepolizumab is a humanised monoclonal antibody that binds interleukin-5 and stops it from attaching to its receptor on eosinophils. IL-5 is the main cytokine for eosinophil maturation, activation and survival, so blood and tissue eosinophils fall. In eosinophilic asthma this reduces exacerbations and the need for oral corticosteroids.

- Mepolizumab binds circulating IL-5
- IL-5 cannot reach its receptor on eosinophils
- Eosinophils mature less and die sooner
- Eosinophilic airway inflammation and flare-ups fall

## Indications

- Severe eosinophilic asthma, as add-on maintenance [Asthma →](https://durgical.com/en/conditions/asthma/)
- COPD with an eosinophilic phenotype [Chronic obstructive pulmonary disease (COPD) →](https://durgical.com/en/conditions/chronic-obstructive-pulmonary-disease/)
- Chronic rhinosinusitis with nasal polyps [Chronic rhinosinusitis and nasal polyps →](https://durgical.com/en/conditions/chronic-rhinosinusitis-and-nasal-polyps/)
- Eosinophilic granulomatosis with polyangiitis (EGPA) [Eosinophilic granulomatosis with polyangiitis (Churg–Strauss) →](https://durgical.com/en/conditions/eosinophilic-granulomatosis-with-polyangiitis/)
- Hypereosinophilic syndrome [Hypereosinophilic syndrome →](https://durgical.com/en/conditions/hypereosinophilic-syndrome/)

## Adverse effects

### Common

- Injection-site pain, redness or swelling
- Headache
- Back pain and muscle spasms
- Dry, itchy skin or eczema

### Serious (rare, important)

- Hypersensitivity reactions: hives, swelling, breathing difficulty, fainting
- Herpes zoster has occurred; vaccination status is reviewed before starting

## Contraindications

- Hypersensitivity to mepolizumab
- Not for acute bronchospasm or status asthmaticus
- Existing helminth infection is treated first

## Key interactions

**Oral and inhaled corticosteroids**
Are not stopped abruptly; dose reduction is gradual and supervised

## What is monitored

- Blood eosinophil count (selection and response)
- Exacerbations and oral corticosteroid use
- Hypersensitivity after injections

## Administration and safety

- Subcutaneous injection in a clinic or at home after training
- Injected into the upper arm, thigh or abdomen; vials, prefilled syringes and autoinjectors exist

## Pregnancy and breastfeeding

Antibodies cross the placenta, especially late in pregnancy; data are limited and use is decided with the specialist.

## Nursing care

- Ask about worm infections and shingles vaccination before starting
- Teach signs of allergic reaction
- Remind that the rescue inhaler is still needed and steroids are not stopped suddenly

## Pharmacokinetics

**Absorption**
Subcutaneous injection, slowly absorbed

**Elimination**
Broken down like other antibodies (proteolysis)

**Onset and duration**
Eosinophils fall within days; clinical benefit builds over weeks to months

## Memory aid

MEPO-lizumab: Mops up Eosinophil Producer (IL-5).

## Test yourself

Think of the answer, then tap the question to see it.

## Which cytokine does mepolizumab block?

Interleukin-5.

## Which blood test helps select patients for mepolizumab?

The blood eosinophil count.

## What are two non-asthma indications of mepolizumab?

EGPA and hypereosinophilic syndrome (also nasal polyps and eosinophilic COPD).

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/mepolizumab/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 2

- [Omalizumab](https://durgical.com/en/pharmacology/omalizumab/)
- [Dupilumab](https://durgical.com/en/pharmacology/dupilumab/)

## Related conditions 5

- [Asthma](https://durgical.com/en/conditions/asthma/)
- [Chronic obstructive pulmonary disease (COPD)](https://durgical.com/en/conditions/chronic-obstructive-pulmonary-disease/)
- [Chronic rhinosinusitis and nasal polyps](https://durgical.com/en/conditions/chronic-rhinosinusitis-and-nasal-polyps/)
- [Eosinophilic granulomatosis with polyangiitis (Churg–Strauss)](https://durgical.com/en/conditions/eosinophilic-granulomatosis-with-polyangiitis/)
- [Hypereosinophilic syndrome](https://durgical.com/en/conditions/hypereosinophilic-syndrome/)

[← Back to the class: Biologics for asthma](https://durgical.com/en/pharmacology/classes/biologics-for-asthma/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Mepolizumab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a615058.html) (MedlinePlus (U.S. National Library of Medicine), 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=R03DX09) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/mepolizumab/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/mepolizumab/