Acetylcysteine Side Effects

Medically reviewed by Drugs.com. Last updated on Jun 7, 2024.

Applies to acetylcysteine: inhalation solution.

Other dosage forms:

• oral capsule, oral solution, oral tablet
• intravenous solution

Serious side effects of acetylcysteine

Along with its needed effects, acetylcysteine 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 as soon as possible if any of the following side effects occur while taking acetylcysteine:

Less common side effects

• wheezing, tightness in chest, or difficulty in breathing (especially in asthma patients)

Rare side effects

• skin rash or other irritation

Other side effects of acetylcysteine

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:

Less common side effects

• clammy skin
• fever
• increase in amount of mucus in lungs
• irritation or soreness of mouth, throat, or lungs
• nausea or vomiting
• runny nose

For patients using a face mask for inhalation of acetylcysteine: the mask may leave a stickiness on your face. This can be removed with water.

When you use acetylcysteine, you may notice that the medicine has an unpleasant odor at first. However, this smell will go away soon after you use the medicine.

For healthcare professionals

Applies to acetylcysteine: compounding powder, inhalation solution, intravenous solution, oral capsule, oral powder for reconstitution, oral tablet, oral tablet effervescent.

General adverse events

The most common adverse events were anaphylactoid reaction, nausea, vomiting, flushing, and skin rash.^[Ref]

Hypersensitivity

• 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]

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]

Gastrointestinal

• Very common (10% or more): Vomiting NOS (12%)
• Common (1% to 10%): Nausea
• Frequency not reported: Stomatitis^[Ref]

Respiratory

• 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]

Respiratory symptoms were defined as presence of any of the following: cough, wheezing, stridor, shortness of breath, chest tightness, respiratory distress, or bronchospasm.^[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]

Frequently asked questions

• What is Fluimucil used for?
• What is NAC and how can it benefit your health?

Further information

Acetylcysteine side effects can vary depending on the individual. 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.

Medical Disclaimer