Zavesca (Miglustat): Uses, Side Effects, Dosing and Cost

Miglustat (brand names Zavesca and Yargesa) is an oral capsule used to treat adults with mild to moderate type 1 Gaucher disease when enzyme replacement therapy is not an option. This guide covers how miglustat works, its side effects, how it is dosed, generic options and what it costs. If you need help paying for it, see our Zavesca (miglustat) copay assistance page.

What Is Miglustat?

Miglustat is a glucosylceramide synthase inhibitor, first approved by the FDA on July 31, 2003, for adults with mild to moderate type 1 Gaucher disease. It is prescribed when enzyme replacement therapy is not a therapeutic option, for example because of allergy, hypersensitivity or poor venous access.

In the United States, miglustat 100 mg capsules are sold as Zavesca, Yargesa and generic miglustat. A separate product, Opfolda (miglustat 65 mg), is approved only in combination with the infused enzyme cipaglucosidase alfa for adults with late-onset Pompe disease who weigh at least 40 kg and are not improving on enzyme replacement therapy.

Gaucher disease is an inherited condition in which a fatty substance called glucosylceramide builds up in the body.

How Does Miglustat Work?

Miglustat slows down the body’s production of glucosylceramide, the substance that builds up in type 1 Gaucher disease. It competitively and reversibly blocks the enzyme needed to make glycosphingolipids, which lowers the rate at which glucosylceramide forms.

Miglustat is absorbed well by mouth (about 97% bioavailability), reaches its peak level in 2 to 2.5 hours, and has a half-life of about 6 to 7 hours. It is not broken down by the liver; it leaves the body unchanged in the urine.

Miglustat Side Effects

The most common miglustat side effects are diarrhea, weight loss, stomach pain, gas, nausea and tremor. In adults treated for type 1 Gaucher disease, Lexidrug lists these as reported in more than 10% of patients:

• Diarrhea, stomach pain, gas, nausea and vomiting
• Weight loss
• Weakness, dizziness, headache and tremor
• Leg cramps and muscle cramps
• Vision problems

Side effects reported in 1% to 10% of patients include bloating, loss of appetite, constipation, indigestion, dry mouth, low platelets, heaviness in the arms or legs, memory problems, migraine, tingling, peripheral neuropathy, unsteady walking, back pain and menstrual changes. Psychosis has been reported after the drug came to market.

Diarrhea was seen in most patients, often with weight loss in the first 12 months, and it decreased over time with continued treatment. It may improve by cutting back on sucrose, lactose and other carbohydrates, taking doses between meals, or using anti-diarrhea medicine.

“Tremor and diarrhea are common side effects in the first months on miglustat.* Tremor often starts in the first month and can ease within one to three months or with a lower dose, and diarrhea may improve by cutting back on sugars, lactose and other carbohydrates or by taking doses between meals.* If either one bothers you, call your doctor or our team before you skip or change a dose, so your treatment plan can be adjusted safely.”

Julia Kravtsova, PharmD, Head Patient Navigator, QuickRx Specialty Pharmacy

*Source: Lexidrug, miglustat monograph (Warnings/Precautions, Adverse Reactions, Administration), last updated 9/21/2026; Zavesca prescribing information, DailyMed. This quote is general information, not medical advice for your own treatment. Do not start, stop, skip or change how you take miglustat without talking to your prescriber, and always follow your prescriber’s instructions and the FDA-approved labeling.

Side effect lists are not complete. Source: Lexidrug, last updated 9/21/2026. Report side effects to your doctor, and to FDA MedWatch at 1-800-FDA-1088.

Serious Warnings and Precautions

The main safety concerns with miglustat are nerve damage in the hands and feet, tremor, ongoing diarrhea and a drop in platelets.

• Peripheral neuropathy: numbness, tingling or burning in the hands or feet has been reported. Neurologic monitoring is required, and treatment may need to stop if symptoms appear.
• Tremor: new or worse tremor usually starts in the first month. It may resolve within 1 to 3 months or respond to a lower dose.
• Platelets: a mild drop in platelet count, without bleeding, has been seen in patients switched from enzyme replacement therapy.
• Allergic reaction: get medical help right away for rash, hives, swelling of the face, lips or throat, or trouble breathing.

Miglustat should be prescribed by a doctor experienced in treating Gaucher disease. Call your doctor about unusual burning, numbness or tingling, weakness, changes in eyesight, unexplained bruising or bleeding, memory problems, shakiness or trouble walking.

How Is Miglustat Taken?

For type 1 Gaucher disease, the labeled adult dose of miglustat is 100 mg by mouth 3 times a day. Your doctor may lower it to 100 mg once or twice a day if you have side effects such as tremor or diarrhea.

• Take it at the same times each day, at regular intervals.
• It can be taken with or without food; taking it between meals may reduce diarrhea.
• If you cannot swallow the capsule, ask your pharmacist first. Lexidrug notes the powder may be mixed into a liquid right before the dose and not stored.

Kidney Dose Adjustments

Because miglustat leaves the body through the kidneys, the labeled Gaucher dose changes with kidney function (CrCl in mL/minute/1.73 m²):

• Above 70: no change
• 50 to 70: 100 mg twice daily
• 30 to 50: 100 mg once daily
• Below 30: use is not recommended

The labeling gives no liver dose changes because this has not been studied; Lexidrug notes an adjustment is unlikely because miglustat is not metabolized by the liver.

Always follow the dose your own prescriber gives you. Source: Lexidrug, last updated 9/21/2026.

What Monitoring Is Needed on Miglustat?

People taking miglustat need a neurologic exam at the start of treatment and every 6 months, plus regular checks of weight, stomach symptoms, platelets and kidney function. The neurologic exam includes checks for new or worsening tremor and signs of peripheral neuropathy. Platelet checks matter most for people whose platelet count was low to begin with.

Does Miglustat Interact With Other Drugs?

Lexidrug lists no known significant drug interactions for miglustat. Even so, tell every doctor and pharmacist about all medicines, supplements and herbal products you take.

One safety note: miglustat can be confused with migalastat, a different drug with a similar name. Lexidrug lists them as a sound-alike, look-alike pair.

Can You Take Miglustat During Pregnancy or Breastfeeding?

Animal studies suggest miglustat may harm an unborn baby, so tell your doctor if you are pregnant or planning a pregnancy. When miglustat is used with cipaglucosidase alfa for Pompe disease, it must not be used during pregnancy, and effective birth control is recommended during treatment and for at least 60 days after the last cipaglucosidase alfa dose.

Miglustat is expected to pass into breast milk, and the manufacturer does not recommend breastfeeding during treatment. Based on a small 6-week study of 7 healthy men, miglustat is not expected to decrease male fertility.

Is There a Generic, and How Much Does Miglustat Cost?

Yes, generic miglustat 100 mg capsules are available in the United States.¹ At Average Wholesale Price (AWP), a 30-day supply at the labeled Gaucher dose works out to roughly $20,276 to $28,933, depending on the product.* Lexidrug lists these AWPs:

*90 capsules = the labeled Gaucher dose of 3 capsules a day for 30 days; simple math for illustration. AWP is a Medi-Span benchmark published in Lexidrug (accessed September 29, 2026). It is a reference price only, not a retail price, not a quote and not what you will pay. Your cost depends on your insurance and any assistance you qualify for.

Copay cards, patient assistance programs and foundation grants may lower what you pay. QuickRx applies on your behalf; eligible patients may pay $0.* Learn more on our Zavesca (miglustat) copay assistance page or call (917) 830-2525.

*Eligibility, benefit amounts and availability are set by each manufacturer or foundation, not by QuickRx. Not all patients qualify, and programs may change or end without notice. Manufacturer copay cards generally cannot be used by patients whose prescriptions are paid for by Medicare, Medicaid or other federal health care programs (HHS OIG, 2014). QuickRx does not issue copay cards.

Is Miglustat Used for Niemann-Pick Disease Type C?

Yes, miglustat is used off-label for Niemann-Pick disease type C, mainly for its neurologic symptoms. Lexidrug cites a randomized controlled trial (Patterson 2007) and consensus clinical management guidelines (Geberhiwot 2018) that recommend miglustat for existing neurologic manifestations of the disease.

Off-label means the use is not approved by the FDA for that condition. Insurance coverage and assistance eligibility for off-label use may differ from approved uses.

How Should Miglustat Be Stored?

Store Zavesca and generic miglustat capsules at room temperature, 20°C to 25°C (68°F to 77°F). Brief exposure to 15°C to 30°C (59°F to 86°F) is allowed. Opfolda should be kept in its original container at the same temperature and protected from light.

Miglustat FAQs

References

1. Miglustat. Lexidrug via UpToDate (Wolters Kluwer Health). Last updated September 21, 2026. Accessed September 29, 2026. (Subscription required.)
2. Zavesca (miglustat) capsules prescribing information. DailyMed, US National Library of Medicine.
3. Miglustat. MedlinePlus, US National Library of Medicine.
4. Gaucher disease. MedlinePlus Genetics, US National Library of Medicine.
5. Patterson MC, Vecchio D, Prady H, et al. Miglustat for treatment of Niemann-Pick C disease: a randomised controlled study. Lancet Neurol. 2007;6(9):765-772. PubMed 17689147
6. Geberhiwot T, Moro A, Dardis A, et al. Consensus clinical management guidelines for Niemann-Pick disease type C. Orphanet J Rare Dis. 2018;13(1):50. PubMed 29625568
7. HHS Office of Inspector General. Special Advisory Bulletin: Pharmaceutical Manufacturer Copayment Coupons. September 2014.

Prescribing information: Zavesca (miglustat). Titusville, NJ: Actelion Pharmaceuticals US Inc; August 2022. Yargesa (miglustat). Parsippany, NJ: Edenbridge Pharmaceuticals LLC; December 2025. Opfolda (miglustat). Philadelphia, PA: Amicus Therapeutics US LLC; July 2024.

Need help paying for miglustat? Call QuickRx at (917) 830-2525 or visit our Zavesca (miglustat) copay assistance page.