Welireg Side Effects

Generic name: belzutifan

Medically reviewed by Drugs.com. Last updated on Feb 17, 2025.

Note: This document provides detailed information about Welireg Side Effects associated with belzutifan. Some dosage forms listed on this page may not apply specifically to the brand name Welireg.

Applies to belzutifan: oral tablet.

Important warnings This medicine can cause some serious health issues

Oral route (tablet)

Warning: Embryo-fetal toxicityExposure to belzutifan during pregnancy can cause embryo-fetal harm.Verify pregnancy status prior to the initiation of belzutifan.Advise patients of these risks and the need for effective non-hormonal contraception.

Belzutifan can render some hormonal contraceptives ineffective.

Serious side effects of Welireg

Along with its needed effects, belzutifan (the active ingredient contained in Welireg) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking belzutifan:

More common side effects

• blurred vision
• change in vision
• chest tightness
• confusion
• cough
• difficulty swallowing
• dizziness
• fast heartbeat
• headache
• hives, itching, skin rash
• nervousness
• pale skin
• pounding in the ears
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• seeing flashes or sparks of light
• seeing floating spots before the eyes, or a veil or curtain appearing across part of vision
• trouble breathing
• unusual bleeding or bruising
• unusual tiredness or weakness

Other side effects of Welireg

Some side effects of belzutifan may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common side effects

• body aches or pain
• chills
• constipation
• difficulty in moving
• ear congestion
• fever
• loss of voice
• muscle aches, cramps, pain, or stiffness
• nausea
• pain in the joints
• sneezing
• sore throat
• stomach pain
• stuffy or runny nose
• swollen joints
• weight increased

For healthcare professionals

Applies to belzutifan: oral tablet.

General adverse events

The most common adverse reactions, including laboratory abnormalities, that occurred during treatment with this drug were anemia, decreased hemoglobin, fatigue, increased creatinine, dizziness, headache, increased glucose, and nausea.^[Ref]

Cardiovascular

• Very common (10% or more): Hypertension (up to 16%)^[Ref]

Gastrointestinal

• Very common (10% or more): Nausea (up to 36%), constipation (up to 21%), abdominal pain (up to 18%), diarrhea (15%)^[Ref]

Hematologic

• Very common (10% or more): Anemia (90%)^[Ref]

Metabolic

• Very common (10% or more): increased weight (up to 16%)^[Ref]

Musculoskeletal

• Very common (10% or more): Myalgia (up to 25%), arthralgia (up to 21%), back pain (13%)^[Ref]

Nervous system

• Very common (10% or more): Headache (up to 44%), dizziness (up to 44%)^[Ref]

Ocular

• Very common (10% or more): Visual impairment (including blurred vision, central retinal vein occlusion, and retinal detachment) (up to 21%)^[Ref]

Other

• Very common (10% or more): Fatigue (up to 70%), peripheral edema (13%), Urinary tract infection (18%), upper respiratory tract infection (including bronchitis, sinusitis, viral upper respiratory infection) (up to 21%), increased creatinine (64%), increased glucose (34%), increased ALT (20%), increased AST (16%), decreased hemoglobin (93%), decreased leukocytes (11%)
• Common (1% to 10%): Decreased corrected calcium, decreased phosphate^[Ref]

Psychiatric

• Very common (10% or more): Insomnia (13%), anxiety (11%)^[Ref]

Respiratory

• Very common (10% or more): Dyspnea (up to 23%)^[Ref]

Further information

Welireg side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer