Casimersen: uses, dosing, side effects & brands
Casimersen 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
- Amondys 45
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How casimersen is dosed
From the FDA label for Amondys 45 (application NDA213026). Other casimersen 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 AMONDYS 45 ( 2.1 ) 30 milligrams per kilogram of body weight once weekly ( 2.2 ) Administer as an intravenous (IV) infusion over 35 to 60 minutes via an in-line 0.2 micron filter ( 2.2 , 2.4 ) Dilution required prior to administration ( 2.3 ) 2.1 Monitoring to Assess Safety Serum cystatin C, urine dipstick, and urine protein-to-creatinine ratio (UPCR) should be measured before starting AMONDYS 45. Consider measurement of glomerular filtration rate prior to initiation of AMONDYS 45. Monitoring for kidney toxicity during treatment is recommended. Obtain the urine sample prior to infusion of AMONDYS 45 or at least 48 hours after infusion [see Warnings and Precautions ( 5.2 )] . 2.2 Dosing Information The recommended dosage of AMONDYS 45 is 30 milligrams per kilogram administered once weekly as a 35 to 60-minute intravenous infusion via an in-line 0.2 micron filter. If a dose of AMONDYS 45 is missed, it may be administered as soon as possible after the scheduled dose. 2.3 Preparation Instructions AMONDYS 45 is supplied in single-dose vials as a preservative-free concentrated solution that requires dilution prior to administration. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and…
Casimersen side effects
The following clinically significant adverse reactions are described elsewhere in the labeling: Hypersensitivity reactions [see Warnings and Precautions ( 5.1 )] The most common adverse reactions (incidence >20% and at least 5% higher than placebo) were upper respiratory tract infection, cough, pyrexia, headache, arthralgia, and oropharyngeal pain. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Sarepta Therapeutics, Inc. at 1-888-SAREPTA (1-888-727-3782) 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 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 the AMONDYS 45 clinical development program, 76 patients received at least one intravenous dose of AMONDYS 45 (30 mg/kg). All patients were male and had genetically confirmed Duchenne muscular dystrophy. Age at study entry was 7 to 20 years (mean 9.9 years). Most (88%) patients were White, and 9% were Asian. AMONDYS 45 was studied in a double-blind, placebo-controlled study (Study 1). Patients in ongoing Study 1 received AMONDYS 45 (n=57) 30 mg/kg or placebo (n=31) intravenously once weekly for up to 96 weeks, after which all patients received or will receive AMONDYS 45 30 mg/kg…
Who shouldn’t take casimersen
AMONDYS 45 is contraindicated in patients with known serious hypersensitivity to casimersen or to any of the inactive ingredients in AMONDYS 45. Instances of hypersensitivity, including angioedema and anaphylaxis, have occurred in patients receiving AMONDYS 45 [see Warnings and Precautions ( 5.1 )] . AMONDYS 45 is contraindicated in patients with serious hypersensitivity to casimersen or to any of the inactive ingredients in AMONDYS 45. ( 4 , 5.1 )
Every casimersen 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: Amondys 45.
What people report to the FDA about casimersen
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 34 reports naming casimersen, and the FDA flagged 74% 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:
- seizure3 reports
- vomiting3 reports
- abdominal pain2 reports
- acute kidney injury2 reports
- acute respiratory failure2 reports
- asthenia2 reports
- diarrhoea2 reports
- infusion related reaction2 reports
Read these as a signal, not a rate. A report does not mean casimersen 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 25, 2026.
Related calculators
Frequently asked questions
What is casimersen?
AMONDYS 45 (casimersen) injection is a sterile, aqueous, preservative-free, concentrated solution for dilution prior to intravenous administration. AMONDYS 45 is a clear to slightly opalescent, colorless liquid and may contain trace amounts of small, white to off-white amorphous particles. AMONDYS 45 is supplied in single-dose vials containing 100 mg casimersen (50 mg/mL). AMONDYS 45 is formulated as an isotonic phosphate buffered saline solution with an osmolality of 260 to 320 mOsm and a pH of 7.5. Each milliliter of AMONDYS 45 contains: 50 mg casimersen; 0.2 mg potassium chloride; 0.2 mg potassium phosphate monobasic; 8 mg sodium chloride; and 1.14 mg sodium phosphate dibasic, anhydrous, in water for injection. The product may contain hydrochloric acid or sodium hydroxide to adjust pH. Casimersen 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). Casimersen contains 22 linked…
Can you take casimersen 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 casimersen 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 casimersen come in?
Across the brands we track, casimersen 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 casimersen?
We do not currently list a generic-labelled casimersen 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). Casimersen: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/casimersen
- MLA
- “Casimersen: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/casimersen.
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 casimersen on DailyMed (NIH) ↗.