Myozyme Side Effects

Generic Name: alglucosidase alfa

Note: This page contains information about the side effects of alglucosidase alfa. Some of the dosage forms included on this document may not apply to the brand name Myozyme.

Not all side effects for Myozyme may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to alglucosidase alfa: intravenous powder for solution

In addition to its needed effects, some unwanted effects may be caused by alglucosidase alfa (the active ingredient contained in Myozyme). In the event that any of these side effects do occur, they may require medical attention.

If any of the following side effects occur while taking alglucosidase alfa, check with your doctor or nurse immediately:

More common
  • Blue lips, fingernails, or skin
  • body aches or pain
  • chest discomfort or pain
  • chills
  • cough
  • difficult or labored breathing
  • difficulty with breathing
  • difficulty with swallowing
  • dizziness
  • dry, red, hot, or irritated skin
  • ear congestion
  • fast, pounding, or irregular heartbeat or pulse
  • feeling of warmth
  • fever
  • headache
  • hives
  • increased sweating
  • irregular, fast, slow, or shallow breathing
  • itching
  • lightheadedness, dizziness, or fainting
  • loss of voice
  • nasal congestion
  • pain
  • pale skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • rapid shallow breathing
  • redness of the face, neck, arms, and occasionally, upper chest
  • redness or pain at the catheter site
  • runny nose
  • shakiness in the legs, arms, hands, or feet
  • shortness of breath
  • skin rash
  • slow or irregular heartbeat
  • sneezing
  • sore throat
  • swollen, painful, or tender lymph glands in the neck, armpit, or groin
  • tightness in the chest
  • trembling or shaking of the hands or feet
  • troubled breathing
  • troubled breathing with exertion
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • wheezing
Less common
  • Blood in the urine
  • convulsions
  • decreased urine
  • dry mouth
  • increased thirst
  • loss of appetite
  • mood changes
  • muscle pain or cramps
  • nausea or vomiting
  • numbness or tingling in the hands, feet, or lips
  • pain in the groin or genitals
  • sharp back pain just below the ribs
Incidence not known
  • Blue-green to black skin discoloration
  • blurred vision
  • confusion
  • dilated neck veins
  • extreme fatigue
  • heart stops
  • inability to speak
  • no breathing
  • no pulse or blood pressure
  • pain, redness, swelling, or sloughing of the skin at the place of injection
  • seizures
  • severe or sudden headache
  • severe pain in the chest
  • slurred speech
  • sudden and severe weakness in the arm or leg on one side of the body
  • sudden onset of severe breathing difficulty
  • swelling of the face, fingers, feet, or lower legs
  • temporary blindness
  • unconscious
  • weight gain

Some of the side effects that can occur with alglucosidase alfa may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Abdominal or stomach pain
  • acid or sour stomach
  • belching
  • body aches or pain
  • change in hearing
  • congestion
  • constipation
  • dryness or soreness of the throat
  • ear discomfort or pain
  • ear drainage
  • earache
  • feeling of constant movement of self or surroundings
  • general feeling of discomfort or illness
  • heartburn
  • hives or welts
  • hoarseness
  • indigestion
  • muscle or bone pain, stiffness, or tightness
  • muscle twitching
  • redness of the skin
  • redness or swelling in the ear
  • sensation of spinning
  • sore mouth or tongue
  • stomach discomfort, upset, or pain
  • stuffy nose
  • tender, swollen glands in the neck
  • trouble with swallowing
  • upper abdominal or stomach pain
  • voice changes
  • white patches in the mouth or on the tongue
Less common
  • Bloody nose
  • sleepiness or unusual drowsiness
Incidence not known
  • Burning, dry, or itching eyes
  • discharge, excessive tearing
  • muscle spasm
  • redness, pain, or swelling of the eye, eyelid, or inner lining of the eyelid

For Healthcare Professionals

Applies to alglucosidase alfa: intravenous powder for injection


Assessment of side effects is based on the exposure of 60 patients with late-onset Pompe disease to alglucosidase alfa (the active ingredient contained in Myozyme) Serious side effects included anaphylaxis, supraventricular tachycardia, coronary artery disease, intervertebral disc protrusion, pneumonia, gastroenteritis, and dehydration. The most common side effects reported were infusion reactions. During postmarketing experience, deaths, and serious adverse reactions have been reported, including anaphylaxis.


Anaphylaxis and severe allergic reactions have been reported during and up to 3 hours after alglucosidase alfa (the active ingredient contained in Myozyme) infusion. Some reactions were life-threatening. At least one patient developed anaphylactic shock during alglucosidase alfa infusion that required life-support measures.

Hypersensitivity side effects have included anaphylaxis (6.7%) and severe allergic reactions. Some reactions were life-threatening and included anaphylactic shock, cardiac arrest, respiratory arrest, apnea, dyspnea, bradycardia, tachycardia, and hypotension. Other accompanying reactions included chest discomfort/pain, throat tightness, bronchospasm, wheezing, tachypnea, cyanosis, decreased oxygen saturation/hypoxia, convulsions, angioedema (including tongue or lip swelling, periorbital edema, and face edema), pruritus, rash, urticaria, hyperhidrosis, nausea, dizziness, hypertension, flushing/erythema, fever, pallor, peripheral coldness, feeling hot, restlessness, nervousness, headache, back pain, and paresthesia. Anaphylactic reactions included angioedema, throat tightness, and chest pain/discomfort.


Infusion reactions are defined as side effects occurring during or within 2 hours after completion of the infusion. Delayed onset infusion reactions are defined as side effects occurring within 48 hours after completion of the infusion.

Infusion reactions were reported in twenty of thirty-nine patients treated with alglucosidase alfa (the active ingredient contained in Myozyme) in clinical studies and appear to be more common in antibody-positive patients. Eight of fifteen patients with high antibody titers experienced infusion reactions whereas none of the three antibody-negative patients experienced infusion reactions.

Other side effects have included infusion reactions, delayed onset infusion reactions, chest discomfort or pain (16.7%), peripheral edema (16.7%), procedural pain (15%), infusion site reactions (13.3%), ear discomfort or pain (11.7%), pain (8.3%), and malaise (5%). Infusion reactions (greater than or equal to 5%) have included anaphylaxis, urticaria, diarrhea, vomiting, dyspnea, pruritus, rash/erythema, pharyngolaryngeal pain, neck pain, hypoacusis, flushing/feeling hot, pain in extremity, fall, and chest discomfort. Additional infusion reactions have included respiratory distress, cough, livedo reticularis, agitation, irritability, retching, rigors, tremor, and increased lacrimation. Delayed onset infusion reactions (greater than or equal to 3%) have included urticaria, dizziness, procedural pain, pharyngolaryngeal pain, malaise, muscle spasms, musculoskeletal pain, musculoskeletal weakness, musculoskeletal stiffness, neck pain, insomnia, and epistaxis. Adverse events resulting in death during postmarketing experience have included sepsis. Infusion reactions reported in at least 2 patients during postmarketing experience included dyspnea, respiratory failure, bronchospasm, stridor, decreased oxygen saturation/hypoxia, pharyngeal edema, chest discomfort, chest pain, hypotension, hypertension, erythema, flushing, lung infection, tachycardia, cyanosis, and hypersensitivity.


During one study, all 59 patients with available samples treated with alglucosidase alfa (the active ingredient contained in Myozyme) developed antibodies to alglucosidase alfa. All patients who developed IgG antibodies did so within the first 3 months of exposure. There was no apparent association between mean or peak IgG antibody titers and the occurrence of side effects.

Testing was performed in patients who experienced moderate to severe or recurrent infusion reactions, for which mast cell activation was suspected. Two of 10 patients evaluated tested positive for alglucosidase alfa specific IgE binding antibodies, both of whom experienced anaphylactic reactions.

Patients who develop IgE antibodies to alglucosidase alfa appear to be at greater risk for anaphylaxis and severe allergic reactions.

Immunologic side effects have included the presence of IgG antibodies to alglucosidase alfa. Systemic immune mediated reactions (including nephrotic syndrome secondary to membranous glomerulonephritis and possible type III immune complex-mediated reactions) have been reported during postmarketing experience.


Cardiovascular side effects have included coronary artery disease. Supraventricular tachycardia was reported in a patient with a history of Wolff-Parkinson-White syndrome. Acute cardiorespiratory failure has been reported in a few infantile-onset Pompe disease patients with underlying cardiac hypertrophy, possibly associated with fluid overload with intravenous administration of alglucosidase alfa (the active ingredient contained in Myozyme) Cardiac arrhythmia, including ventricular fibrillation, ventricular tachycardia, and bradycardia, resulting in cardiac arrest or death, or requiring cardiac resuscitation or defibrillation have been reported in infantile-onset Pompe disease patients with cardiac hypertrophy (associated with the use of general anesthesia for the placement of a central venous catheter intended for alglucosidase alfa infusion). Adverse events resulting in death during postmarketing experience have included cardiorespiratory arrest, cardiac failure, and aortic dissection.


Musculoskeletal side effects have included musculoskeletal pain (36.7%), musculoskeletal stiffness or tightness (15%), muscle twitching (8.3%), and intervertebral disc protrusion.

Nervous system

Nervous system side effects have included hypoacusis (33.3%), vertigo (6.7%), tremor (6.7%), and somnolence (5%). Adverse events resulting in death during postmarketing experience have included cerebrovascular accident.


Gastrointestinal side effects have included vomiting (21.7%), constipation (10%), gastroenteritis (10%), and dyspepsia (8.3%). Abdominal pain has been reported during postmarketing experience.


Respiratory side effects have included upper respiratory tract infection (18.3%), exertional dyspnea (6.7%), epistaxis (5%), respiratory tract infection (5%), and pneumonia. Adverse events resulting in death during postmarketing experience have included respiratory failure, hemothorax, and pneumothorax.


Dermatologic side effects have included urticaria (10%), pruritus (10%), and hyperhidrosis (8.3%). Severe cutaneous reactions (including necrotizing skin lesions) have been reported during postmarketing experience. Adverse events resulting in death during postmarketing experience have included skin necrosis.


Hematologic side effects have included lymphadenopathy (8.3%).


Metabolic side effects have included hypokalemia (5%) and dehydration.


Ocular side effects have included blurred vision (5%).


Renal side effects have included nephrolithiasis (5%). Nephrotic syndrome has been reported during postmarketing experience.


Genitourinary side effects have included proteinuria during postmarketing experience.


Endocrine side effects have included at least 1 case of hyperparathyroidism during postmarketing experience.

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