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Zavesca Side Effects

Generic Name: miglustat

Note: This page contains side effects data for the generic drug miglustat. It is possible that some of the dosage forms included below may not apply to the brand name Zavesca.

It is possible that some side effects of Zavesca may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to miglustat: oral capsule

As well as its needed effects, miglustat (the active ingredient contained in Zavesca) may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking miglustat, check with your doctor immediately:

More common
  • Black, tarry stools
  • bleeding gums
  • blood in the urine or stools
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • diarrhea
  • pinpoint red spots on the skin
  • trembling or shaking in the hands
  • unsteadiness or awkwardness
  • unusual bleeding or bruising
  • weakness in the arms, hands, legs, or feet
  • weight loss

Some miglustat side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common
  • Back pain
  • bloated or full feeling
  • blurred or loss of vision
  • difficulty having a bowel movement (stool)
  • disturbed color perception
  • dizziness
  • double vision
  • dry mouth
  • excess air or gas in the stomach or intestines
  • halos around lights
  • headache
  • heartburn
  • heaviness in the limbs
  • indigestion
  • leg cramps
  • loss of appetite
  • memory loss
  • menstrual changes
  • nausea
  • pain or discomfort in the chest, upper stomach, or throat
  • passing gas
  • stomach discomfort, upset or pain
  • swelling of the abdominal or stomach area
  • tunnel vision
  • unsteady walk
  • vomiting

For Healthcare Professionals

Applies to miglustat: oral capsule


The most common serious side effect was peripheral neuropathy. Diarrhea and tremor were the side effects that required intervention most often.[Ref]


Osmotic diarrhea appears to be due to inhibitory activity of miglustat (the active ingredient contained in Zavesca) on intestinal disaccharidases leading to reduced absorption of dietary disaccharides in the small intestine. Diarrhea decreased over time with continued therapy.[Ref]

Very common (10% or more): Diarrhea (including osmotic diarrhea; up to 100%), abdominal pain (up to 67%), flatulence (up to 50%), nausea (up to 22%), vomiting (up to 11%)
Common (1% to 10%): Constipation, dry mouth, dyspepsia, epigastric pain not food-related, bloating
Frequency not reported: Dysphagia[Ref]


Very common (10% or more): Weight decrease (up to 67%)
Common (1% to 10%): Anorexia[Ref]

Nervous system

Very common (10% or more): Tremor/exacerbation of existing tremor (about 30%), headache (up to 22%), tremor (up to 17%), dizziness (up to 11%), leg cramps (up to 11%)
Common (1% to 10%): Unsteady gait, paresthesia, migraine, peripheral neuropathy
Frequency not reported: Gait abnormal, gait spastic, ataxia, hyperreflexia[Ref]


Very common (10% or more): Generalized weakness (up to 17%)
Common (1% to 10%): Abdominal distension, back pain, heaviness in limbs, pain
Frequency not reported: Abdominal distension with gas, fatigue, lacerations[Ref]


Very common (10% or more): Visual disturbances (up to 17%)[Ref]


Very common (10% or more): Cramps (up to 11%)[Ref]


Common (1% to 10%): Memory loss
Frequency not reported: Insomnia, decreased appetite, depression[Ref]


Common (1% to 10%): Thrombocytopenia
Frequency not reported: Mild reduction in platelet count[Ref]


Common (1% to 10%): Menstrual disorder[Ref]


Frequency not reported: Nasopharyngitis, cough, sinusitis


1. "Product Information. Zavesca (miglustat)." Acetelion Pharmaceuticals US, Inc, South San Francisco, CA.

2. Patterson MC, Vecchio D, Prady H, Abel L, Wraith JE "Miglustat for treatment of Niemann-Pick C disease: a randomised controlled study." Lancet Neurol 6 (2007): 765-72

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