Belumosudil (Rezurock®)

Author: Christina Bach, MBE, LCSW, OSW-C
Content Contributor: Colleen Timlin, PharmD, BCOP - Oncology Clinical Pharmacy Specialist
Last Reviewed: November 21, 2023

Pronounce: BEL-ue-MOE-soo-dil

Classification: Kinase inhibitor; rho kinase 2 (ROCK 2) inhibitor

About: Belumosudil (Rezurock®)

Belumosudil is a kinase inhibitor. A kinase is an enzyme that promotes cell growth. There are many types of kinases, which control different phases of cell growth.

Belumosudil is a type of targeted therapy that blocks a protein called “rho kinase 2” or “Rho-associated coiled-coil kinase 2” (ROCK 2; ROCK-II). Belumosudil inhibits the activity of ROCK 2 in cells, blocking the signaling pathway and reducing inflammation caused by ROCK 2. This medication is used to treat chronic graft versus host disease (cGvHD).

How to Take Belumosudil (Rezurock®)

Belumosudil is taken as a tablet by mouth once a day, with food and a glass of water. Swallow the tablet whole. Do not crush, chew, or cut the tablet. Take the tablet with a meal at about the same time every day. If a dose of belumosudil is missed, it should be taken as soon as possible on the same day with a return to the normal schedule the next day. Do not take extra doses to make up for the missed dose.

It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed.

Tell your provider if you have a history of kidney or liver problems. Your provider will do blood tests at least once a month while taking belumosudil to check your liver.

The blood levels of this medication can be affected by certain foods and medications. Be sure to tell your healthcare provider about all medications and supplements you take. Depending on which medications you take, your provider may have you take one tablet two times a day. Ask your provider what your specific dose should be.

Storage and Handling

Store your medication in the original, labeled container at room temperature and in a dry location (unless otherwise directed by your healthcare provider or pharmacist). This medication should not be stored in a pillbox. The original, labeled container will have a desiccant tablet to keep the tablets dry from any moisture. Keep this desiccant in the bottle. Keep containers out of reach of children and pets.

Where do I get this medication?

Belumosudil is available through select specialty pharmacies. Your oncology team will work with your prescription drug plan to identify an in-network specialty pharmacy for the distribution of this medication and shipment directly to your home.

Insurance Information

This medication may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals depending upon prescription drug coverage. Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, may also be available. Your care team can help you find these resources if they are available.

Possible Side Effects of Belumosudil

There are a number of things you can do to manage the side effects of belumosudil. Talk to your care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important side effects:

Infection and Low White Blood Cell Count (Leukopenia or Neutropenia)

This medication can cause life-threatening infections, with or without a decrease in white blood cell counts.

White blood cells (WBC) are important for fighting infection. While receiving treatment, your WBC count can drop, putting you at a higher risk of getting an infection. You should let your doctor or nurse know right away if you have a fever (temperature greater than 100.4°F or 38°C), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.

Tips to preventing infection:

  • Washing hands, both yours and your visitors, is the best way to prevent the spread of infection.
  • Avoid large crowds and people who are sick (i.e.: those who have a cold, fever, or cough or live with someone with these symptoms).
  • When working in your yard, wear protective clothing including long pants and gloves.
  • Do not handle pet waste.
  • Keep all cuts or scratches clean.
  • Shower or bathe daily and perform frequent mouth care.
  • Do not cut cuticles or ingrown nails. You may wear nail polish, but not fake nails.
  • Ask your oncology care team before scheduling dental appointments or procedures.
  • Ask your oncology care team before you, or someone you live with, has any vaccinations.


Fatigue is very common during cancer treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on cancer treatment, and for a period after, you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team for helpful tips on dealing with this side effect.

Nausea and/or Vomiting

Talk to your oncology care team so they can prescribe medications to help you manage nausea and vomiting. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try saltines, or ginger ale to lessen symptoms.

Call your oncology care team if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.

Electrolyte Abnormalities

This medication can affect the normal levels of electrolytes(phosphate, potassium, calcium, etc.) in your body. Your levels will be monitored using blood tests. If your levels become too low, your care team may prescribe specific electrolytes to be given by IV or taken by mouth. Do not take any supplements without first consulting with your care team.

Low Platelet Count (Thrombocytopenia)

Platelets help your blood clot, so when the count is low you are at a higher risk of bleeding. Let your oncology care team know if you have any excess bruising or bleeding, including nose bleeds, bleeding gums, or blood in your urine or stool. If the platelet count becomes too low, you may receive a transfusion of platelets.

  • Do not use a razor (an electric razor is fine).
  • Avoid contact sports and activities that can result in injury or bleeding.
  • Do not take aspirin (salicylic acid), non-steroidal, anti-inflammatory medications (NSAIDs) such as Motrin/Advil (ibuprofen), Aleve (naproxen), Celebrex (celecoxib), etc. as these can all increase the risk of bleeding. Please consult with your healthcare team regarding the use of these agents and all over-the-counter medications/supplements while on therapy.
  • Do not floss or use toothpicks and use a soft-bristle toothbrush to brush your teeth.

Low Red Blood Cell Count (Anemia)

Your red blood cells are responsible for carrying oxygen to the tissues in your body. When the red cell count is low, you may feel tired or weak. You should let your oncology care team know if you experience any shortness of breath, difficulty breathing, or pain in your chest. If the count gets too low, you may receive a blood transfusion.


Your oncology care team can recommend medications to relieve diarrhea. Also, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole grain bread, cereals, and seeds. Soluble fiber is found in some foods and absorbs fluid, which can help relieve diarrhea. Foods high in soluble fiber include applesauce, bananas (ripe), canned fruit, orange sections, boiled potatoes, white rice, products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses of non-alcoholic, uncaffeinated fluid a day to prevent dehydration.

Shortness of Breath and Cough

Some people taking this medication may become short of breath or may develop a new or worsening cough. If you become short of breath or it is more severe than what is normal for you, you should let your provider know. If you develop a cough or it changes from what is normal for you, you should call your provider. If you are having a hard time breathing, call 911 or go to the Emergency Room right away.

Peripheral Edema

Peripheral edema is swelling of the extremities caused by the retention of fluid. It can cause swelling of the hands, arms, legs, ankles, and feet. The swelling can become uncomfortable. Notify your oncology care team if you are experiencing any new or worsening swelling.

Abdominal (Belly) Pain

This medication can cause you to have pain in your abdomen (belly). Call your provider if this pain becomes severe, or if you have a hard time eating, drinking, or doing daily activities.

Hemorrhage (Bleeding)

Patients may experience minor bleeding, such as a nosebleed. Serious bleeding has also occurred in patients treated with this medication, including coughing up blood, bleeding into the stomach, blood in stool, vomiting blood, bleeding in the brain (stroke), nosebleeds, and blood in the urine. People who have had serious bleeding should not take this medication. These events are uncommon, though if they occur, belumosudil should be discontinued. While a nosebleed may not seem like much of a concern, you should notify your healthcare team right away if you develop bleeding of any sort.

Muscle or Joint Pain/Aches and Headache

Your healthcare provider can recommend medications and other strategies to help relieve pain.

High Blood Pressure

This medication can cause high blood pressure (hypertension). Patients should have their blood pressure checked regularly during therapy. Any hypertension should be treated appropriately. If hypertension cannot be controlled, the medication may be stopped. Report any headaches, vision changes, or dizziness to your oncology care team.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. Effective birth control is necessary during treatment and for at least 1 week after treatment. Even if your menstrual cycle stops or you believe you are not producing sperm, you could still be fertile and conceive. This medication may affect your fertility, so you may want to consider sperm banking or egg harvesting if you wish to have a child in the future. Discuss these options with your oncology team. You should not breastfeed while receiving this medication and for at least 1 week after the last dose.