NAC Side Effects

Generic name: acetylcysteine

Medically reviewed by Drugs.com. Last updated on Dec 4, 2024.

Note: This document provides detailed information about NAC Side Effects associated with acetylcysteine. Some dosage forms listed on this page may not apply specifically to the brand name NAC.

Applies to acetylcysteine: intravenous solution.

Other dosage forms:

• oral capsule, oral solution, oral tablet
• inhalation 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:

More common side effects

• fast heartbeat
• feeling of warmth
• fever
• hives or welts, itching, or skin rash
• hoarseness
• irritation
• joint pain, stiffness, or swelling
• redness of the face, neck, arms, and occasionally, upper chest
• redness of the skin
• swelling of the eyelids, face, lips, hands, or feet
• tightness in the chest
• trouble breathing or swallowing

Less common side effects

• cough
• fast, pounding, or irregular heartbeat or pulse
• noisy breathing

Rare side effects

• confusion
• dizziness
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• sweating
• 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 side effects

• nausea
• vomiting

Less common side effects

• body aches or pain
• congestion
• dryness or soreness of the throat
• fever
• hoarseness
• runny nose
• tender, swollen glands in the neck
• voice changes

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

Further information

NAC 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.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer