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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.

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.

Major Side Effects

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

Minor Side Effects

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 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 (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, 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

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]

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

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

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

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.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.