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Sapropterin Side Effects

In Summary

Commonly reported side effects of sapropterin include: headache and rhinorrhea. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to sapropterin: oral powder for solution, oral tablet disintegrating

Along with its needed effects, sapropterin 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 sapropterin:

More common Incidence not known
  • Burning feeling in the chest or stomach
  • cough
  • difficulty with swallowing
  • dizziness
  • fast heartbeat
  • fidgeting or moving around too much
  • indigestion
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • skin rash, hives, or itching
  • stomach upset
  • talking too much
  • tenderness in the stomach area
  • tightness in the chest
  • unusual tiredness or weakness

Some side effects of sapropterin 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 Less common
  • Stuffy nose

For Healthcare Professionals

Applies to sapropterin: oral powder for reconstitution, oral tablet dispersible


In phenylketonuria (PKU) trials, the most common side effects were headache, rhinorrhea, pharyngolaryngeal pain, diarrhea, vomiting, cough, and nasal congestion.

In clinical trials for non-PKU indications, a different formulation was used in patients with disorders other than PKU; some had underlying neurologic disorders or cardiovascular disease. Common side effects were headache, peripheral edema, arthralgia, polyuria, agitation, dizziness, nausea, pharyngitis, abdominal pain, upper abdominal pain, and upper respiratory tract infection. Serious and severe side effects included convulsions, exacerbation of convulsions, dizziness, gastrointestinal bleeding, postprocedural bleeding, headache, irritability, myocardial infarction, overstimulation, and respiratory failure.[Ref]

Nervous system

Very common (10% or more): Headache (15%)
Common (1% to 10%): Dizziness
Frequency not reported: Convulsions, exacerbation of convulsions, overstimulation
Postmarketing reports: Hyperactivity[Ref]


Very common (10% or more): Rhinorrhea (11%), pharyngolaryngeal pain (10%)
Common (1% to 10%): Cough, nasal congestion, pharyngitis, upper respiratory tract infection
Frequency not reported: Respiratory failure
Postmarketing reports: Pharyngitis[Ref]


Very common (10% or more): Low phenylalanine levels
Common (1% to 10%): Hypophenylalaninemia[Ref]


Common (1% to 10%): Diarrhea, vomiting, nausea, abdominal pain, upper abdominal pain
Frequency not reported: Gastrointestinal bleeding
Postmarketing reports: Oropharyngeal pain, esophageal pain, gastritis, dyspepsia, abdominal pain, nausea, vomiting[Ref]


Frequency not reported: Myocardial infarction[Ref]


Common (1% to 10%): Peripheral edema
Frequency not reported: Contusion, postprocedural bleeding, pyrexia[Ref]


Common (1% to 10%): Agitation
Frequency not reported: Irritability


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


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


Postmarketing reports: Hypersensitivity reactions (including serious allergic reactions, anaphylaxis, rash)[Ref]


Frequency not reported: Rash[Ref]


Frequency not reported: Increased GGT[Ref]


1. "Product Information. Kuvan (sapropterin)." BioMarin Pharmaceutical Inc, Novato, CA.

2. Dubois EA, Cohen AF "Sapropterin." Br J Clin Pharmacol 69 (2010): 576-7

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

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

Some side effects of sapropterin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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.