Blenrep is a treatment option for certain types of blood cancer.

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).

Blenrep has an active ingredient belantamab mafodotin. 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

The kilogram is 2.2 pounds.

The section covers standard dosage and administration information. Your doctor will discuss Blenrep instructions for you when you start your treatment.

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?

100 milligrams is the strength of Blenrep.

What are the usual dosages of Blenrep?

The body weight is the basis for the Blenrep dosage. Your doctor will calculate your dose using your weight.

The information below is about the dosages that are commonly used. Your doctor will make a decision on the best dose.

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 grams of body weight every 3 weeks.

The weight is 2.2 lbs.

Is Blenrep used long term?

If you and your doctor determine that Blenrep is safe and effective for you, it may be used as a long-term treatment.

If your condition gets worse or you have side effects from the medication, your doctor may want you to stop taking it.

Dosage adjustments

If you have serious side effects from Blenrep, your doctor may reduce your dose.

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 side effects from the IV, the healthcare professional may temporarily stop giving the IV. They may restart the infusion at a slower rate once you are symptom free. Your doctor may stop your Blenrep treatment if your side effects are very severe.

Before starting Blenrep treatment, you will need to have a vision check. You will need to have your vision checked before you receive the drug and if you have any vision changes.

If you develop vision problems from this medication, your doctor may recommend a dose reduction.

* 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 amount of Blenrep you are prescribed may depend on a number of factors.

  • Your body weight.
  • You can see side effects from this medication.

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 lasts about 30 minutes. If you have serious side effects, your healthcare professional may give you the medication more slowly. They may stop the injection temporarily.

You need to have an eye care professional check your vision before you receive any Blenrep. They will determine if it is safe for you to receive the Blenrep injection.

It is important to keep your Blenrep appointments. If you think you might miss an appointment, call your doctor.

Setting a reminder on your phone or writing it down on a calendar will help you make it to your appointment.

The dosages of Blenrep are usually described in the sections above. If your doctor recommends Blenrep, they will prescribe the correct amount.

If you have questions about your current Blenrep dosage, talk to your doctor. Some examples of questions you may want to ask them.

  • Will my Blenrep dosage change if I lose weight?
  • Can I receive my Blenrep injection over an hour instead of 30 minutes?
  • Should my dosage increase if Blenrep is not working 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.

Researchers have not studied how Blenrep works in people with more severe problems.

Let your doctor know if you have any problems with the kidneys. They will decide if it is safe to take Blenrep and recommend the best dose for you.

If you have questions about Blenrep, you should talk to your doctor.

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