If you have a certain type of blood cancer, your doctor might suggest Blenrep as a treatment option for you.

Blenrep is a prescription medication used in adults to treat multiple myeloma in certain situations. It’s a biologic, which means that it’s made from living cells.

Blenrep comes as a powder that a healthcare professional mixes with liquid to make a solution. They’ll give you Blenrep as an intravenous (IV) infusion (an injection into your vein given over time).

The active ingredient in Blenrep is belantamab mafodotin-blmf. An active ingredient is what makes a drug work.

This article describes the dosages of Blenrep, its strength, and how to take the drug. To learn more about Blenrep, see this in-depth article.

Note: The chart below highlights the basics of Blenrep’s dosage. Be sure to read on for more details. And keep in mind that this article covers Blenrep’s standard dosage schedule, which is provided by the drug’s manufacturer. But your doctor will prescribe the Blenrep dosage that’s right for you.

Recommended Blenrep dosage Recommended Blenrep dose reduction, if needed
2.5 milligrams per kilograms* (mg/kg) of body weight 1.9 mg/kg of body weight

* One kilogram (kg) is about 2.2 pounds (lbs.).

This section covers standard dosage and administration information for Blenrep. Before you start your Blenrep treatment, your doctor will discuss Blenrep dosing instructions specific to your condition.

What is Blenrep’s form?

Blenrep comes as a powder that a healthcare professional mixes to make a solution. They’ll give you the solution as an intravenous (IV) infusion (an injection in your vein given over time).

What strength does Blenrep come in?

Blenrep comes in one strength: 100 milligrams (mg).

What are the usual dosages of Blenrep?

The dosage of Blenrep is based on body weight. Your doctor will calculate your dosage using your weight in kilograms (kg).*

The information below describes dosages that are commonly used or recommended. Your doctor will determine the best dosage to fit your needs.

For treating multiple myeloma in certain situations, the recommended Blenrep dosage is 2.5 mg/kg of body weight. A healthcare professional will give you this dose once every 3 weeks as an IV infusion.

If you have serious side effects from Blenrep, your doctor may suggest a dose reduction. They’ll ultimately recommend a dosing schedule effective for your condition but has the least risk of side effects.

The recommended dose reduction for Blenrep is 1.9 mg/kg of body weight given once every 3 weeks.

* One kg is about 2.2 lbs.

Is Blenrep used long term?

Yes, Blenrep may be used as a long-term treatment if you and your doctor determine this medication is safe and effective for you.

If your condition worsens or you have bothersome side effects from this medication, your doctor may have you stop Blenrep treatment.

Dosage adjustments

If you have severe side effects from Blenrep, your doctor may reduce your dosage.

For example, if you develop very low levels of platelets (cells that help your blood clot) during Blenrep treatment, your doctor may lower your dosage. Or they may have you temporarily stop receiving the drug until your platelet levels are higher.

If you develop bothersome side effects from the IV infusion, the healthcare professional giving the infusion may temporarily stop it. Once your symptoms ease, they may restart the infusion at a slower rate. If your side effects are very severe, your doctor may permanently stop your Blenrep treatment.

Your doctor will refer you to an eye care professional for a vision check before starting Blenrep treatment. You’ll also need your vision checked before you receive each dose of the drug and if you report any vision changes.

Your doctor may recommend a dose reduction if you develop serious vision problems* from this medication.

* Blenrep has a boxed warning for the risk of serious eye problems. A boxed warning is a serious warning from the Food and Drug Administration (FDA). For more information, see the “Boxed warning” section at the beginning of this article.

The dosage of Blenrep you’re prescribed may depend on several factors, including:

  • your body weight
  • side effects you may have from this medication (see “Dosage adjustments” under “What is Blenrep’s dosage?”)

A healthcare professional will give you Blenrep as an intravenous (IV) infusion (an injection into your vein given over time) once every 3 weeks. You’ll need to go to a doctor’s office, hospital, or clinic for your dose.

The infusion typically lasts about 30 minutes. But if you have serious side effects during the infusion, your healthcare professional may give you the medication more slowly. Or they may stop the infusion temporarily.

You’ll need to have an eye care professional check your vision before each Blenrep dose you receive. They’ll determine if it’s safe for you to receive your Blenrep infusion.

It’s important to keep your Blenrep infusion appointments. If you think you might miss an appointment, call your doctor’s office right away to reschedule.

To help ensure you don’t miss an appointment, try writing down a reminder on a calendar or setting one on your phone.

The sections above describe the usual dosages of Blenrep provided by the drug’s manufacturer. If your doctor recommends Blenrep for you, they’ll prescribe the dosage that’s right for you.

Talk with your doctor if you have questions or concerns about your current Blenrep dosage. Here are some examples of questions you may want to ask them:

  • Will my Blenrep dosage need to change if I lose weight?
  • Can receiving my Blenrep infusion over 1 hour instead of 30 minutes reduce my risk of side effects from this medication?
  • Should my dosage increase if Blenrep is not working well for me?

For more information about what side effects Blenrep may cause, see this article.


Will I need a lower Blenrep dosage if I have kidney problems?



If you have mild or moderate kidney problems, you likely will not need a Blenrep dose reduction. Studies have shown that how Blenrep is processed in the body isn’t affected by mild or moderate kidney problems.

But researchers have not studied how Blenrep works in people with more severe kidney problems.

Before starting Blenrep treatment, let your doctor know about any kidney problems you have. They’ll decide if it’s safe for you to take Blenrep and recommend the dosage that best fits your condition.

If you have questions about Blenrep dosage and kidney function, talk with your doctor.

The Healinggeeks Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.