WHY is this medicine prescribed?
Mepolizumab injection is used alone or with other medications
Mepolizumab injection is in a class of medications called monoclonal antibodies. It works by blocking the action of a certain natural substance in the body that causes inflammation.
HOW should this medicine be used?
Mepolizumab injection comes as a prefilled syringe, a prefilled autoinjector, or as a powder to be mixed with water and injected subcutaneously (just under the skin). Give once every 4 weeks. Your doctor will determine the length of your treatment based on your condition and how well you respond to the medication.
Use mepolizumab injection exactly as directed. Do not inject more or less of it or inject it more often than prescribed by your doctor.
You may receive your first dose of mepolizumab injection in your doctor's office. After that, your doctor may allow you or a caregiver to give the injections at home. Before you use mepolizumab injection yourself the first time, read the manufacturer's information for the patient that comes with the medication. Ask your doctor or pharmacist to show you or your caregiver how to inject it.
Use each syringe or autoinjector only once and inject all of the solution in the syringe or autoinjector. Dispose of used syringes or autoinjectors in a puncture-resistant container. Talk to your doctor or pharmacist about how to dispose of the puncture-resistant container.
Remove the prefilled syringe or autoinjector from the refrigerator. Place it on a flat surface without removing the needle cap and allow it to warm to room temperature for 30 minutes (no longer than 8 hours) before you are ready to inject the medication. Do not try to warm the medication by heating it in a microwave, placing it in hot water, leaving it in sunlight, or through any other method.
Do not shake a syringe that contains mepolizumab.
Continue to take or use all other medications that your doctor has prescribed to treat your condition. Do not decrease your dose of any other medication or stop taking any other medication that has been prescribed by your doctor unless your doctor tells you to do so. Your doctor may want to decrease the doses of your other medications gradually.
Always look at mepolizumab solution before injecting it. Check that the expiration date has not passed and that the liquid is clear and colorless or slightly yellow to slightly brown. The liquid should not contain visible particles. Do not use a syringe that is frozen or if the liquid is cloudy or contains small particles.
You can inject mepolizumab injection anywhere on the front of your thighs (upper leg) or stomach except your navel (belly button) and the area 2 inches (5 centimeters) around it. If a caregiver injects the medication, the back of the upper arm may also be used. To reduce the chances of soreness or redness, use a different site for each injection. Do not inject into an area where the skin is tender, bruised, red, or hard or where you have scars or stretch marks.
Mepolizumab injection is not used to treat sudden attacks of breathing problems caused by asthma or COPD. Talk to your doctor about how to treat symptoms of a sudden breathing problem. If your asthma or COPD symptoms get worse or if you have breathing problems more often, talk to your doctor.
Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.
Are there OTHER USES for this medication?
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What SPECIAL PRECAUTIONS should I follow?
Before receiving mepolizumab injection,
What SPECIAL DIETARY instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do IF I FORGET to take a dose?
Use the missed dose as soon as you remember it and then continue your regular dosing schedule. Do not use a double dose to make up for a missed one. Call your doctor if you miss a dose and have questions about what to do.
What SIDE EFFECTS can this medicine cause?
Mepolizumab injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
Some side effects can be serious. If you experience any of these symptoms or those listed in the SPECIAL PRECAUTIONS section, call your doctor immediately or get emergency medical treatment:
Mepolizumab injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
What should I do in case of OVERDOSE?
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at http://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
What should I know about STORAGE and DISPOSAL of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store mepolizumab injection in the refrigerator or in an unopened carton at room temperature for up to 7 days, but do not freeze it. Once removed from the carton, mepolizumab injection can be stored at room temperature for up to 8 hours.
Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location - one that is up and away and out of their sight and reach. http://www.upandaway.org
Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website http://goo.gl/c4Rm4p for more information.
What OTHER INFORMATION should I know?
Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to mepolizumab injection.
Ask your pharmacist any questions you have about mepolizumab injection.
Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.
This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.
The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.
AHFS® Patient Medication Information™ Copyright, 2025. The American Society of Health-System Pharmacists®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Selected Revisions: August 15, 2025.