Note: This document contains side effect information about acetylcysteine. Some dosage forms listed on this page may not apply to the brand name NAC.
Applies to acetylcysteine: oral capsule, oral solution, oral tablet. Other dosage forms:
- inhalation solution
- intravenous solution
Serious side effects of NAC
Along with its needed effects, acetylcysteine (the active ingredient contained in NAC) 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 or nurse immediately if any of the following side effects occur while taking acetylcysteine:
Incidence not known
- Difficulty with breathing or swallowing
- fever
- hives or itching
- nausea
- rash with or without a fever
- reddening of the skin, especially around the ears
- severe or ongoing vomiting
- swelling of the eyes, face, or inside of the nose
- unusual tiredness or weakness
Other side effects of NAC
Some side effects of acetylcysteine 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
- Mild nausea
- stomach upset
- vomiting
For Healthcare Professionals
Applies to acetylcysteine: compounding powder, inhalation solution, intravenous solution, oral capsule, oral tablet, oral tablet effervescent.
General
The most common adverse events were anaphylactoid reaction, nausea, vomiting, flushing, and skin rash.[Ref]
Hypersensitivity
Anaphylactoid symptoms include airway obstruction (bronchospasm), angioedema, dyspnea, hypotension, shock, tachycardia, urticaria, and injection site reaction (including rash). These are most common either during, or at the end of the loading dose infusion, and may be dose related. Careful monitoring is recommended.[Ref]
Very common (10% or more): Anaphylactoid reaction (18%)
Uncommon (0.1% to 1%): Anaphylaxis
Rare (less than 0.1%): Acquired sensitization
Frequency not reported: Dermal eruptions[Ref]
Gastrointestinal
Very common (10% or more): Vomiting NOS (12%)
Common (1% to 10%): Nausea
Frequency not reported: Stomatitis[Ref]
Respiratory
Respiratory symptoms were defined as presence of any of the following: cough, wheezing, stridor, shortness of breath, chest tightness, respiratory distress, or bronchospasm.[Ref]
Common (1% to 10%): Respiratory symptoms, pharyngitis, rhinorrhea, rhonchi, throat tightness
Frequency not reported: Bronchoconstriction, bronchospasm, irritation to tracheal and bronchial tract (inhalation route), hemoptysis, dyspnea, respiratory arrest, coughing, stridor[Ref]
Cardiovascular
Common (1% to 10%): Tachycardia
Uncommon (0.1% to 1%): Hypotension
Frequency not reported: Cyanosis, tachycardia, bradycardia, cardiac arrest, extrasystoles, flushing, hypertension, vasodilation, ECG changes[Ref]
Dermatologic
Common (1% to 10%): Urticaria/facial flushing, rash NOS, pruritus, flushing
Frequency not reported: Angioedema, sweating, edema periorbital, clamminess[Ref]
Metabolic
Common (1% to 10%): Edema
Frequency not reported: Acidosis, hypokalemia[Ref]
Other
Rare (less than 0.1%): Death
Frequency not reported: Fever, malaise, rigors, chest pain, facial pain, facial edema, raised temperature[Ref]
Nervous system
Frequency not reported: Syncope, generalized seizure, drowsiness[Ref]
Local
Frequency not reported: Injection site reaction[Ref]
Musculoskeletal
Frequency not reported: Arthralgia, arthropathy[Ref]
Hepatic
Frequency not reported: Deterioration of liver function[Ref]
Hematologic
Frequency not reported: Thrombocytopenia[Ref]
Ocular
Frequency not reported: Blurred vision, eye pain, puffy eyes, itching/redness/irritation in eyes (ophthalmic formulation)[Ref]
Psychiatric
Frequency not reported: Anxiety[Ref]
