Skip to main content

Viltolarsen Side Effects

Medically reviewed by Last updated on Oct 25, 2021.

For the Consumer

Applies to viltolarsen: intravenous solution

Side effects requiring immediate medical attention

Along with its needed effects, viltolarsen 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 or nurse immediately if any of the following side effects occur while taking viltolarsen:

More common

  • Body aches or pain
  • chills
  • cough
  • confusion
  • diarrhea
  • difficulty in moving
  • ear congestion
  • fast, pounding, or irregular heartbeat
  • fever
  • headache
  • joint pain
  • loss of voice
  • muscle pain or stiffness
  • nausea
  • runny or stuffy nose
  • sneezing
  • sore throat
  • stomach pain
  • swelling of the face, ankles, or hands
  • trouble breathing
  • unusual bruising
  • unusual tiredness or weakness
  • vomiting

Incidence not known

Side effects not requiring immediate medical attention

Some side effects of viltolarsen 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

  • Bleeding, blistering, burning, coldness, discoloration of skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
  • hives or welts, itching, skin rash
  • redness of the skin

For Healthcare Professionals

Applies to viltolarsen: intravenous solution


The most reported adverse reactions with this drug have included upper respiratory tract infection, injection site reaction, cough, and pyrexia.[Ref]


Upper respiratory tract infection includes upper respiratory tract infection, nasopharyngitis, and rhinorrhea.

Very common (10% or more): Upper respiratory tract infection (up to 63%), cough (19%)


Injection site reactions include injection site bruising, injection site erythema, injection site reaction, and injection site swelling.

Very common (10% or more): Injection site reaction (25%)


Common (1% to 10%): Diarrhea (13%), vomiting 13%, abdominal pain (13%)


Kidney toxicity, including potentially fatal glomerulonephritis, has been observed after administration of some antisense oligonucleotides. To date, it has not been reported in clinical trials with this drug, but clinical experience is limited. In juvenile male mice injected weekly with escalating doses of this drug, there was a dose-dependent increase in the incidence and severity of renal tubular effects (including degeneration), which were not accompanied by clinical pathology correlates.

Other antisense oligonucleotides:

Frequency not reported: Kidney toxicity including potentially fatal glomerulonephritis


Very common (10% or more): Pyrexia (19%), contusion (13%)


Very common (10% or more): Arthralgia (13%)


Very common (10% or more): Urticaria (13%)


Very common (10% or more): Ejection fraction decreased (13%)

Frequently asked questions


1. "Product Information. Viltepso (viltolarsen)." NS Pharma, Paramus, NJ.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.