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Palynziq Side Effects

Generic name: pegvaliase

Medically reviewed by Last updated on Feb 6, 2024.

Note: This document contains side effect information about pegvaliase. Some dosage forms listed on this page may not apply to the brand name Palynziq.

Applies to pegvaliase: subcutaneous solution.


Subcutaneous route (Solution)

Anaphylaxis has been reported after administration of pegvaliase-pqpz and may occur at any time during treatment. Administer the initial dose of pegvaliase-pqpz under the supervision of a healthcare provider equipped to manage anaphylaxis, and closely observe patients for at least 60 minutes following injection. Prior to self-injection, confirm patient competency with self-administration, and patient’s and observer’s ability to recognize signs and symptoms of anaphylaxis and to administer auto-injectable epinephrine, if needed. Prescribe auto-injectable epinephrine. Prior to first dose, instruct the patient and observer (if applicable) on its appropriate use. Instruct the patient to seek immediate medical care upon its use. Instruct patients to carry auto-injectable epinephrine with them at all times during pegvaliase-pqpz treatment. Pegvaliase-pqpz is available only through a restricted program called the Palynziq(TM) REMS.

Serious side effects of Palynziq

Along with its needed effects, pegvaliase (the active ingredient contained in Palynziq) 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 pegvaliase:

More common


Other side effects of Palynziq

Some side effects of pegvaliase 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

For Healthcare Professionals

Applies to pegvaliase: subcutaneous solution.


The most commonly reported adverse reactions have included injection site reactions, arthralgia, hypersensitivity reactions, headache, generalized skin reactions lasting at least 14 days, pruritus, nausea, abdominal pain, oropharyngeal pain, vomiting, cough, diarrhea, and fatigue.[Ref]


Very common (10% or more): Hypersensitivity reactions (up to 65%)

Common (1% to 10%): Anaphylaxis, acute systemic hypersensitivity reaction, serum sickness[Ref]

During clinical trials, a total of 42 anaphylactic episodes were reported in 29 patients (n=285). The rate of anaphylaxis was highest during induction and titration phase. Signs and symptoms of anaphylaxis included syncope, hypotension, hypoxia, dyspnea, wheezing, chest discomfort/chest tightness, tachycardia, angioedema (swelling of face, lips, eyes, tongue), throat tightness, skin flushing, rash, urticaria, pruritus, and gastrointestinal symptoms (vomiting, nausea, diarrhea). Anaphylaxis occurred within 1 hour in 81% (34/42) of the reported anaphylaxis episodes. Most episodes occurred within the first year of dosing (69%, 29/42 episodes), however, cases also occurred after one year of dosing and up to 1604 days (4.4 years) into treatment. Twenty one out of the 29 (72%) patients who experienced anaphylaxis were rechallenged and 6 out of the 21 (29%) had recurrence of anaphylaxis. All anaphylaxis episodes resolved without sequelae.

Hypersensitivity reactions other than anaphylaxis have been reported in 72% of patients (204/285). Hypersensitivity reactions have included rash, urticaria, anaphylaxis, rash generalized, hypersensitivity, rash erythematous, rash maculo-papular, rash pruritic, serum sickness, swelling face, dermatitis contact, swollen tongue, lip swelling, rash macular, pharyngeal edema, injection site hypersensitivity, eczema, drug eruption, dermatitis allergic, dermatitis, tongue edema, palatal edema, edema mouth, multiple allergies, lip edema, eye edema, exfoliative rash, drug hypersensitivity, dermatitis atopic, dermatitis acneiform, pruritus allergic, mouth swelling, implant site rash, gingival swelling, face edema, eyelid edema, eye swelling, dermatitis psoriasiform, dermatitis infected, conjunctivitis allergic, bronchospasm, angioedema, allergic sinusitis, allergic cough, eczema nummular, and rhinitis allergic.[Ref]


Very common (10% or more): Anti-phenylalanine ammonia lyase (PAL) immunoglobulin G (IgG) antibodies (up to 99.6%), anti-PAL IgM antibodies (up to 98%), anti-drug IgE antibodies (up to 96%), sustained total anti-drug antibody response (up to 91%), neutralizing antibodies (up to 89%), complement factor C3 decreased (up to 84%), complement factor C4 decreased (up to 64%)[Ref]


Very common (10% or more): Injection site reactions (up to 93%)[Ref]

Injection site reactions have included: Erythema, pruritus, pain, bruising, rash, swelling, urticaria, induration, hemorrhage, edema, mass, inflammation, nodule, discoloration, warmth, hematoma, irritation, vesicles, hypersensitivity, papule, discomfort, scar, paresthesia, hypertrophy, extravasation, scab, and dryness[Ref]


Very common (10% or more): Arthralgia (up to 86%), blood creatinine phosphokinase above upper limit of normal (up to 48%), myalgia (up to 12%)

Common (1% to 10%): Joint swelling, musculoskeletal stiffness, joint stiffness[Ref]

Arthralgia included: Pain in extremity, back pain, musculoskeletal pain, and neck pain[Ref]


Very common (10% or more): C-reactive protein (CRP) above upper limit of normal (up to 71%), fatigue (up to 24%), high sensitivity CRP levels increased (up to 17%)[Ref]


Hypophenylalaninemia (blood phenylalanine level below 30 micromol/L) on a single measurement was reported in up to 65% of patients; hypophenylalaninemia on at least 2 consecutive measurements was reported in up to 49% of patients.[Ref]

Very common (10% or more): Hypophenylalaninemia (up to 65%)[Ref]

Nervous system

Headache included migraine and sinus headache.[Ref]

Very common (10% or more): Headache (up to 56%), dizziness (up to 21%)[Ref]


Generalized skin reactions included pruritus, rash, urticaria, dry skin, rash erythematous, erythema, cellulitis, rash macular, pruritus generalized, petechiae, dermatitis allergic, skin infection, skin induration, rash maculopapular, rash generalized, pharyngeal edema, macule, granulomatous dermatitis, exfoliative rash, drug eruption, dermatitis atopic, dermatitis, xanthogranuloma, skin plaque, skin mass, skin lesion, skin hypopigmentation, skin hyperpigmentation, skin exfoliation, septal panniculitis, scar, rash pruritic, rash papular, psoriatic arthropathy, pruritus allergic, papule, necrobiosis lipoidica diabeticorum, furuncle, eczema, ecchymosis, dermatitis psoriasiform, dermatitis infected, blister, eczema nummular, granuloma, infected dermal cyst, lipohypertrophy, psoriasis, and skin irritation.[Ref]

Very common (10% or more): Generalized skin reaction lasting at least 14 days (up to 47%), rash (up to 33%), pruritus (up to 27%), urticaria (up to 25%), alopecia (up to 21%), erythema (up to 11%)

Common (1% to 10%): Skin exfoliation, maculopapular rash, angioedema[Ref]


Abdominal pain included upper abdominal pain and abdominal discomfort.[Ref]

Very common (10% or more): Nausea (up to 31%), abdominal pain (up to 30%), oropharyngeal pain (up to 29%), vomiting (up to 30%), diarrhea (up to 27%)[Ref]


Very common (10% or more): Cough (up to 30%), nasal congestion (up to 27%)[Ref]


Very common (10% or more): Anxiety (up to 21%)[Ref]


Very common (10% or more): Lymphadenopathy (up to 16%)[Ref]

Frequently asked questions


1. Cerner Multum, Inc. "Australian Product Information."

2. (2018) "Product Information. Palynziq (pegvaliase)." BioMarin Pharmaceutical Inc

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.