Viltolarsen: uses, dosing, side effects & brands
Viltolarsen is a medicine sold in the U.S. under one brand, for duchenne muscular dystrophy. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Treats
- Duchenne Muscular Dystrophy
- Available as
- Injectable
- Sold as
- Viltepso
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How viltolarsen is dosed
From the FDA label for Viltepso (application NDA212154). Other viltolarsen products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Serum cystatin C, urine dipstick, and urine protein-to-creatinine ratio should be measured before starting VILTEPSO. ( 2.1 ) Recommended dosage is 80 milligrams per kilogram of body weight once weekly. ( 2.2 ) Administer as an intravenous infusion over 60 minutes. ( 2.2 , 2.4 ) If the volume of VILTEPSO required is less than 100 mL, dilution in 0.9% Sodium Chloride Injection, USP, is required. ( 2.3 ) 2.1 Monitoring to Assess Safety Serum cystatin C, urine dipstick, and urine protein-to-creatinine ratio should be measured before starting VILTEPSO. Consider measurement of glomerular filtration rate prior to initiation of VILTEPSO. Monitoring for kidney toxicity during treatment is recommended. Obtain the urine samples prior to infusion of VILTEPSO or at least 48 hours after the most recent infusion [see Warnings and Precautions ( 5.1 )]. 2.2 Dosing Information The recommended dosage of VILTEPSO is 80 mg/kg administered once weekly as a 60-minute intravenous infusion. If a dose of VILTEPSO is missed, it should be administered as soon as possible after the scheduled dose time. 2.3 Preparation Instructions Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Prepare the VILTEPSO dose using aseptic technique. Calculate the total dose of VILTEPSO to be administered based on the…
Viltolarsen side effects
The most common adverse reactions (incidence ≥15% in patients treated with VILTEPSO) were upper respiratory tract infection, injection site reaction, cough, and pyrexia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact NS Pharma at 1-866 NSPHARM (1-866-677-4276) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. In clinical trials with VILTEPSO, 32 patients have been exposed to VILTEPSO once weekly, ranging between 40 mg/kg (0.5 times the recommended dosage) and 80 mg/kg (the recommended dosage), including 16 patients treated for greater than 12 months and 8 patients treated for greater than 24 months as part of an ongoing open-label extension study. All patients were male and had genetically confirmed DMD. Study 1 was a multicenter, 2-period, dose-finding study conducted in the United States and Canada in males 4 years to less than 10 years of age on a stable corticosteroid regimen for at least 3 months. During the initial period (first 4 weeks) of Study 1, patients were randomized (double-blind) to VILTEPSO or placebo. All patients then received 20 weeks of VILTEPSO 40 mg/kg once…
Who shouldn’t take viltolarsen
None. None ( 4 )
Every viltolarsen product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Viltepso.
What people report to the FDA about viltolarsen
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 40 reports naming viltolarsen, and the FDA flagged 33% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- illness6 reports
- pyrexia4 reports
- infusion site swelling3 reports
- malaise3 reports
- vomiting3 reports
- catheter site infection2 reports
- cough2 reports
- fall2 reports
Read these as a signal, not a rate. A report does not mean viltolarsen caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 26, 2026.
Related calculators
Frequently asked questions
What is viltolarsen?
VILTEPSO (viltolarsen) injection is a sterile, preservative-free, aqueous solution for intravenous administration. VILTEPSO is a clear and colorless solution. VILTEPSO is supplied in single-dose vials containing 250 mg/5 mL viltolarsen (50 mg/mL) in 0.9% sodium chloride. Each milliliter of VILTEPSO contains 50 mg viltolarsen and 9 mg sodium chloride in water for injection. The final product is adjusted to a pH ranging between 7.0 and 7.5 using hydrochloric acid and/or sodium hydroxide. Viltolarsen is an antisense oligonucleotide of the phosphorodiamidate morpholino oligomer (PMO) subclass. PMOs are synthetic molecules in which the five-membered ribofuranosyl rings found in natural DNA and RNA are replaced by a six-membered morpholino ring. Each morpholino ring is linked through an uncharged phosphorodiamidate moiety rather than the negatively charged phosphate linkage that is present in natural DNA and RNA. Each phosphorodiamidate morpholino subunit contains one of the heterocyclic bases found in DNA (adenine, cytosine, guanine, or thymine). Viltolarsen contains 21 linked subunits.
Can you take viltolarsen with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run viltolarsen against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does viltolarsen come in?
Across the brands we track, viltolarsen is currently marketed as injectable, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic viltolarsen?
We do not currently list a generic-labelled viltolarsen product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Viltolarsen: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/viltolarsen
- MLA
- “Viltolarsen: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/viltolarsen.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for viltolarsen on DailyMed (NIH) ↗.