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Miglustat Side Effects

Medically reviewed by Last updated on Jun 4, 2022.

For the Consumer

Applies to miglustat: oral capsule

Side effects requiring immediate medical attention

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

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

Side effects not requiring immediate medical attention

Some side effects of miglustat 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

  • 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 commonly reported adverse reactions included diarrhea, flatulence, abdominal pain, weight loss, and tremor; the most common serious adverse reaction was peripheral neuropathy; diarrhea and tremor were the side effects that most commonly required intervention.[Ref]


Osmotic diarrhea appears to be due to inhibitory activity of miglustat 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, stomach pain, gas, abdominal distension/discomfort

Frequency not reported: Dysphagia, indigestion, dry mouth[Ref]


Weight loss has been observed in approximately 55% to 65% of patients. Peak weight loss occurs between 6 and 12 months, with a mean weight loss of 6% to 7% of body weight. It is unclear if weight loss results from the diarrhea and associated gastrointestinal complaints, a decrease in food intake, or a combination of these or other factors. There is a trend to return to baseline weight after the first year.[Ref]

Very common (10% or more): Weight decrease (up to 67%)

Common (1% to 10%): Anorexia[Ref]

Nervous system

The most common serious adverse reaction in clinical trials was peripheral neuropathy. Tremor, and worsening tremor were very commonly reported. Compared to the general population, patients with type 1 Gaucher disease are more likely to have peripheral neuropathy. A patient should be evaluated for tremor and neuropathy prior to starting therapy.[Ref]

Very common (10% or more): Tremor/exacerbation of existing tremor (about 30%), headache (up to 22%), tremor (up to 17%), dizziness (up to 11%)

Common (1% to 10%): Unsteady gait, paresthesia, migraine, peripheral neuropathy, ataxia, hypoesthesia

Frequency not reported: Gait abnormal, gait spastic, hyperreflexia[Ref]


Very common (10% or more): Generalized weakness (up to 17%)

Common (1% to 10%):Fatigue, asthenia, chills, malaise, pain

Frequency not reported: Fatigue, lacerations[Ref]


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


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

Common (1% to 10%): Muscle spasms

Frequency not reported: Leg cramps, muscle cramps, back pain, heaviness in arms and legs[Ref]


Common (1% to 10%): Memory loss

Frequency not reported: Insomnia, decreased appetite, depression, decreased libido[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[Ref]


1. "Product Information. Zavesca (miglustat)." Actelion Pharmaceuticals US Inc (2003):

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. Cerner Multum, Inc. "Australian Product Information." O 0

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.