Acetylcysteine inhalation

Name: Acetylcysteine inhalation

What is the most important information I should know about acetylcysteine inhalation?

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Acetylcysteine inhalation side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using acetylcysteine inhalation and call your doctor at once if you have:

  • chest tightness; or

  • trouble breathing.

Common side effects may include:

  • sticky feeling around the nebulizer mask;

  • white patches or sores inside your mouth or on your lips;

  • nausea, vomiting;

  • fever, runny nose, sore throat;

  • drowsiness; or

  • cold and clammy skin.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.



With the administration of acetylcysteine, the patient may initially observe a slight disagreeable odor that is soon not noticeable. With a face mask there may be stickiness on the face after nebulization. This is easily removed by washing with water.

Under certain conditions, a color change may occur in the opened bottle of acetylcysteine. The light purple color is the result of a chemical reaction which does not significantly affect the safety or mucolytic effectiveness of acetylcysteine.

Continued nebulization of acetylcysteine solution with a dry gas will result in an increased concentration of the drug in the nebulizer because of evaporation of the solvent. Extreme concentration may impede nebulization and efficient delivery of the drug. Dilution of the nebulizing solution with appropriate amounts of Sterile Water for Injection, USP, as concentration occurs, will obviate this problem.

Drug Interactions

Drug stability and safety of acetylcysteine when mixed with other drugs in a nebulizer have not been established.

Carcinogenesis, Mutagenesis, Impairment of Fertility:


Carcinogenicity studies in laboratory animals have not been performed with acetylcysteine alone, nor with acetylcysteine in combination with isoproterenol.

Long-term oral studies of acetylcysteine alone in rats (12 months of treatment followed by 6 months of observation) at doses up to 1,000 mg/kg/day (5.2 times the human mucolytic dose) provided no evidence of oncogenic activity.


Published data1 indicate that acetylcysteine is not mutagenic in the Ames test, both with and without metabolic activation.

Impairment of Fertility

A reproductive toxicity test to assess potential impairment of fertility was performed with acetylcysteine (10%) combined with isoproterenol (0.05%) and administered as an aerosol into a chamber of 12.43 cubic meters. The combination was administered for 25, 30, or 35 minutes twice a day for 68 days before mating, to 200 male and 150 female rats; no adverse effects were noted in dams or pups. Females after mating were continued on treatment for the next 42 days.

Reproductive toxicity studies of acetylcysteine in the rat given oral doses of acetylcysteine up to 1,000 mg/kg (5.2 times the human mucolytic dose) have also been reported in the literature.1 The only adverse effect observed was a slight non-dose-related reduction in fertility at dose levels of 500 or 1,000 mg/kg/day (2.6 or 5.2 times the human mucolytic dose) in the Segment I study.

Pregnancy: Teratogenic Effects: Pregnancy Category B

In a teratology study of acetylcysteine in the rabbit, oral doses of 500 mg/kg/day (2.6 times the human mucolytic dose) were administered to pregnant does by intubation on days 6 through 16 of gestation. Acetylcysteine was found to be nonteratogenic under the conditions of the study.

In the rabbit, two groups (one of 14 and one of 16 pregnant females) were exposed to an aerosol of 10% acetylcysteine and 0.05% isoproterenol hydrochloride for 30 and 35 minutes twice a day from the 6th through the 18th day of pregnancy. No teratogenic effects were observed among the offspring.

Teratology and a perinatal or postnatal toxicity study in rats were performed with a combination of acetylcysteine and isoproterenol administered by the inhalation route. In the rat, two groups of 25 pregnant females each were exposed to the aerosol for 30 and 35 minutes, respectively, twice a day from the 6th through the 15th day of gestation. No teratogenic effects were observed among the offspring.

In the pregnant rat (30 rats per group), twice-daily exposure to an aerosol of acetylcysteine and isoproterenol for 30 or 35 minutes from the 15th day of gestation through the 21st day postpartum was without adverse effect on dams or newborns.

Reproduction studies of acetylcysteine with isoproterenol have been performed in rats and of acetylcysteine alone in rabbits at doses up to 2.6 times the human dose. These have revealed no evidence of impaired fertility or harm to the fetus due to acetylcysteine. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies may not always be predictive of human responses, this drug should be used during pregnancy only if clearly needed.

Nursing Mothers

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when acetylcysteine is administered to a nursing woman.



  1. Blair D, Rumack, BH, Clin Chem, 1977; 23(4):743-745.
  2. Howie D, Andriaenssens Pl, Prescott LF. J. Pharm Pharmacol, 1977; 29(4):235-237. GLC
  3. Prescott LF. J. Pharm Pharmacol, 1971; 23(10):807-808. Colorimetric
  4. Glynn JP. Kendal SE, Lancet 1975; 1(May 17):1147-1148.

Supportive Treatment of Acetaminophen Overdose

  1. Maintain fluid and electrolyte balance based on clinical evaluation of state of hydration and serum electrolytes.
  2. Treat as necessary for hypoglycemia.
  3. Administer vitamin K1 if prothrombin time ratio exceeds 1.5 or fresh frozen plasma if the prothrombin time ratio exceeds 3.0.
  4. Diuretics and forced diuresis should be avoided.


Store unopened vials at 20°-25°C (68°-77°F); excursions permitted to 15°-30°C (59°-86°F) (see USP Controlled Room Temperature).

Acetylcysteine solution does not contain an antimicrobial agent, and care must be taken to minimize contamination of the sterile solution. Dilutions of acetylcysteine should be used freshly prepared and utilized within one hour. If only a portion of the solution in a vial is used, store the remaining undiluted portion in a refrigerator and use within 96 hours.  A change in color may occur after opening.  This does not change the efficacy of the drug.

PRINCIPAL DISPLAY PANEL - 4 mL (20%) Container & Carton

NDC 0517-7604-25


20% (200 mg/mL)

Rx Only

For Inhalation (Mucolytic Agent) or Oral
Administration (Acetaminophen Antidote)




20% (200 mg/mL)

NDC 0517-7604-25
25 x 4 mL VIALS

For Inhalation (Mucolytic Agent) or Oral Administration (Acetaminophen Antidote)

Rx Only

Each mL contains: Acetylcysteine 200 mg (20%), Edetate Disodium 0.025%, Water for Injection q.s. pH adjusted with Sodium Hydroxide and, if necessary, Hydrochloric Acid is added. pH (range 6.0 to 7.5).
Store at 20° to 25°C (68° to 77°F) (See USP Controlled Room Temperature).
STORE IN REFRIGERATOR 2° to 8°C (36° to 46°F) AFTER OPENING. A change in color may occur after opening. This does not change the efficacy of the drug. Acetylcysteine may be diluted to a lesser concentration with an appropriate solution.
Directions for Use: See Package Insert.


Rev. 11/11