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N - ACETYL CYSTEINE

Other Names:

Acetyl Cysteine, Acétyl Cystéine, Acetylcysteine, Acétylcystéine, Chlorhydrate de Cystéine, Cysteine, Cystéine, Cysteine Hydrochloride, Cystine, Hydrochlorure de Cystéine, L-Cysteine, L-Cystéine, L-Cysteine HCl, L-Cystéine HCl, NAC, N-Acetil Cis...
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N-ACETYL CYSTEINE Overview
N-ACETYL CYSTEINE Uses
N-ACETYL CYSTEINE Side Effects
N-ACETYL CYSTEINE Interactions
N-ACETYL CYSTEINE Dosing
N-ACETYL CYSTEINE Overview Information

N-acetyl cysteine comes from the amino acid L-cysteine. Amino acids are the building blocks of proteins. N-acetyl cysteine has many uses as medicine.

N-acetyl cysteine is used to counteract acetaminophen (Tylenol) and carbon monoxide poisoning. It is also used for chest pain (unstable angina), bile duct blockage in infants, amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease), Alzheimer’s disease, allergic reactions to the anti-seizure drug phenytoin (Dilantin), and an eye infection called keratoconjunctivitis. It is also used for reducing levels of a type of cholesterol called lipoprotein (a), homocysteine levels (a possible risk factor for heart disease) and the risk of heart attack and stroke in patients with serious kidney disease.

Some people use N-acetyl cysteine for chronic bronchitis, chronic obstructive pulmonary disease (COPD), hay fever, a lung condition called fibrosing alveolitis, head and neck cancer, and lung cancer. It is also used for treating some forms of epilepsy; ear infections; complications of kidney dialysis; chronic fatigue syndrome (CFS); an autoimmune disorder called Sjogren’s syndrome; preventing sports injury complications; radiation treatment; increasing immunity to flu and H1N1 (swine) flu; and for detoxifying heavy metals such as mercury, lead, and cadmium.

N-acetyl cysteine is also used for preventing alcoholic liver damage; for protecting against environmental pollutants including carbon monoxide, chloroform, urethanes and certain herbicides; for reducing toxicity of ifosfamide and doxorubicin, drugs that are used for cancer treatment; as a hangover remedy; for preventing kidney damage due to certain X-ray dyes; and for human immunodeficiency virus (HIV).

Healthcare providers give N-acetyl cysteine intravenously (by IV) for acetaminophen overdose, acrylonitrile poisoning, amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease), kidney failure in the presence of liver disease (hepatorenal syndrome), chest pain in combination with nitroglycerin, heart attack in combination with nitroglycerin and streptokinase, and for helping to prevent multi-organ failure leading to death.

N-acetyl cysteine is sometimes inhaled (breathed into the lungs) or delivered through a tube in the throat to treat certain lung disorders such as pneumonia, bronchitis, emphysema, cystic fibrosis, and others.

How does it work?

N-acetyl cysteine treats acetaminophen (Tylenol) poisoning by binding the poisonous forms of acetaminophen that are formed in the liver. It is also an antioxidant, so it may play a role in preventing cancer.

N-ACETYL CYSTEINE Uses & Effectiveness What is this?

Effective for:

  • Acetaminophen (Tylenol) poisoning. N-acetyl cysteine is effective in reducing the death rate and preventing the permanent harm caused by acetaminophen poisoning. For this use, N-acetyl cysteine given by mouth is as effective as N-acetyl cysteine given intravenously (by IV).
  • Collapse of part or all of a lung (atelectasis). N-acetyl cysteine helps treat collapsed lungs caused by mucus blockage.
  • Diagnostic lung tests. N-acetyl cysteine is helpful when used to prepare people for diagnostic lung tests.
  • Care of people with a tube in their windpipe (people who have undergone a tracheostomy). N-acetyl cysteine helps prevent crusting in people with a tube in their windpipe.

Possibly Effective for:

  • Chest pain (angina). Taking N-acetyl cysteine by mouth or injecting it intravenously (by IV) seems to improve chest pain when used with the drug nitroglycerin. Intravenous N-acetyl cysteine seems to help prevent nitroglycerin tolerance. Oral N-acetyl cysteine might help prevent nitroglycerin tolerance, but results are conflicting.
  • Bipolar disorder. Taking N-acetyl cysteine by mouth seems to help reduce depression symptoms in people with bipolar disorder.
  • Air passage swelling (bronchitis). Taking N-acetyl cysteine by mouth seems to reduce shortness of breath in people with air passage swelling due to mustard gas exposure. Also, taking N-acetyl cysteine by mouth for 3-6 months seems to prevent flare-ups in people with persistent air passage swelling. However, taking it for less time does not seem to be effective.
  • A lung disease called chronic obstructive pulmonary disease (COPD). Taking N-acetyl cysteine by mouth seems to decrease flare-ups by about 40% and improve sputum (phlegm) consistency in people with COPD. However, it might increase the risk of blockage of the breathing tube.
  • Kidney problems caused by dyes used during some X-ray exams. Taking N-acetyl cysteine by mouth seems to help prevent kidney problems caused by dyes used during some X-ray exams in people with severely reduced kidney function (kidney insufficiency). It might help prevent these problems in people with moderately reduced kidney function. It does not seem to lower the risk of kidney problems caused by dyes used during X-ray exams in people with normal kidney function.
  • Serious kidney disease. Taking N-acetyl cysteine by mouth seems to help prevent problems, such as heart attack and stroke, in people with serious kidney disease. The risk reduction can be as much as 40%. However, N-acetyl cysteine doesn’t reduce the overall risk of death or the risk of death from heart disease in these people.
  • Epilepsy seizures. Taking N-acetyl cysteine by mouth seems to help treat a certain type of epilepsy seizure.
  • A lung disease called fibrosing alveolitis. Taking N-acetyl cysteine by mouth seems to improve lung function in people with fibrosing alveolitis.
  • High levels of homocysteine. Taking N-acetyl cysteine by mouth seems to reduce homocysteine levels, a possible risk factor for heart disease.
  • High levels of blood fat. Taking N-acetyl cysteine by mouth seems to reduce levels of a blood fat called lipoprotein(a) in people with high levels of this blood fat at baseline.
  • Ifosfamide (Ifex) side effects. Taking N-acetyl cysteine by mouth seems to help prevent side effects of ifosfamide (Ifex), which is used for certain types of cancer. However the drug mesna (Mesnex) seems to work better than N-acetyl cysteine.
  • Flu. Taking N-acetyl cysteine by mouth seems to reduce flu symptoms.
  • Heart attack. Injecting N-acetyl cysteine intravenously (by IV) seems to help maintain heart function in people having a heart attack when given with the drugs nitroglycerin and streptokinase.
  • Tolerance to nitrate. Injecting N-acetyl cysteine intravenously (by IV) seems to help prevent tolerance to nitrate. Oral N-acetyl cysteine might help prevent nitrate tolerance, but results are conflicting.
  • Hair pulling. Taking N-acetyl cysteine by mouth seems to decrease hair pulling by up to 40%.

Possibly Ineffective for:

  • Amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease). Injecting N-acetyl cysteine intravenously (by IV) doesn’t seem to improve ALS symptoms.
  • Breathing problems in premature infants. Giving N-acetyl cysteine through a hole in the windpipe does not seem to prevent breathing problems in premature infants.
  • Cystic fibrosis. Taking N-acetyl cysteine by mouth or breathing it in doesn’t seem to improve lung function in people with cystic fibrosis. However, N-acetyl cysteine might reduce markers of swelling in people with cystic fibrosis when taken by mouth in high doses.
  • Doxorubicin side effects. Taking N-acetyl cysteine by mouth doesn’t seem to prevent or treat side effects of doxorubicin, a drug used to treat certain types of cancer.
  • A condition that causes sensitivity to light (Erythropoietic protoporphyria, EPP). Taking N-acetyl cysteine by mouth doesn’t seem to prevent sensitivity to light in people with EPP.
  • Hepatitis. Taking N-acetyl cysteine by mouth doesn’t seem to help treat viral hepatitis. It also doesn’t seem to improve response to interferon therapy in people with hepatitis C. However, it might help prevent relapses in people with hepatitis C.
  • HIV/AIDS. Taking N-acetyl cysteine by mouth doesn’t seem to improve immune function or reduce the amount of virus in the body in most people with HIV. However, it might improve immune function in people with HIV who have low levels of glutathione, a chemical in the body that is formed from N-acetyl cysteine.
  • Low blood pressure. Taking N-acetyl cysteine by mouth doesn’t seem to reduce the risk of kidney failure in people with long-term low blood pressure.
  • Kidney disease. Taking N-acetyl cysteine doesn’t seem to improve long-term kidney disease.
  • Liver transplant. Injecting N-acetyl cysteine intravenously (by IV) during surgery to donate a liver and keeping the liver in a cold liquid containing N-acetyl cysteine before the liver transplant doesn’t seem to prevent transplant rejection.
  • Pancreas swelling (pancreatitis). Taking N-acetyl cysteine by mouth doesn’t prevent pancreatitis in people undergoing a certain diagnostic procedure that can cause pancreas swelling. Also, injecting N-acetyl cysteine intravenously along with selenium and vitamin C doesn’t seem to prevent pancreas dysfunction in people with serious pancreatitis.
  • Bone loss after menopause. Taking N-acetyl cysteine by mouth doesn’t seem to prevent bone loss after menopause.
  • Recovery after surgery. Taking N-acetyl cysteine by mouth or injecting it intravenously (by IV) doesn’t seem to reduce the risk of heart attack, stroke, kidney injury, or death after heart surgery. N-acetyl cysteine might help prevent abnormal heartbeats after heart surgery, but results are conflicting.

Likely Ineffective for:

  • Alzheimer’s disease. Taking N-acetyl cysteine by mouth doesn’t improve symptoms of Alzheimer’s disease.
  • Head and neck cancer. Taking N-acetyl cysteine by mouth doesn’t prevent new tumors or improve survival in people with head and neck cancer.
  • Lung cancer. Taking N-acetyl cysteine by mouth doesn’t prevent new tumors or improve survival in people with lung cancer.
  • Treating organ failure. Injecting N-acetyl cysteine intravenously (by IV) might increase the risk of death in people with multiple organ failure.

Insufficient Evidence for:

  • A life-threatening lung condition (acute respiratory distress syndrome, ARDS). Some research shows that injecting N-acetyl cysteine intravenously (by IV) reduces the risk of death and improves some aspects of lung function in people with ARDS. However, conflicting research exists.
  • Adrenoleukodystrophy (ALD). Early research suggests that taking N-acetyl cysteine by mouth or injecting it intravenously (by IV) might improve survival and stabilize brain function in some people with ALD.
  • Altitude sickness. Early research suggests that taking N-acetyl cysteine doesn’t prevent anorexia or other eating problems associated with altitude sickness.
  • Asthma. Early research suggests that breathing in a combination of N-acetyl cysteine plus isoproterenol improves lung function and decreases sputum (phlegm) thickness in people with asthma.
  • Heart bypass surgery. Early research suggests that N-acetyl cysteine does not prevent death or improve outcomes after surgery in patients undergoing heart bypass surgery.
  • Cocaine dependence. Some early research shows that taking N-acetyl cysteine by mouth reduces the desire to use cocaine in people who are cocaine dependent. However, conflicting results exist.
  • Colon cancer. Taking N-acetyl cysteine by mouth may reduce the likelihood of colon and rectal cancer in patients with a history of adenomatous colon polyps.
  • Dental plaque. Early research suggests that using a mouthwash containing 10% N-acetyl cysteine may reduce plaque.
  • Dry eye syndrome. Early research suggests that using a tear solution containing 20% acetyl cysteine improves some but not all symptoms of dry eye syndrome.
  • Exercise performance. Early research suggests that injecting N-acetyl cysteine intravenously (by IV) before and during exercise increases the time until fatigue in trained athletes.
  • Gambling addiction. Early research suggests that taking N-acetyl cysteine by mouth might reduce the desire to gamble compared to baseline. However, N-acetyl cysteine appears to work only as well as inactive (placebo) treatment.
  • Helicobacter pylori (H. pylori) infection. Some research suggests that taking N-acetyl cysteine by mouth along with usual treatment for H. pylori infection increases the number of people who experience complete infection elimination. However, other early research suggests that taking N-acetyl cysteine along with curcumin, bovine lactoferrin, and the drug pantoprazole does not help eliminate H. pylori infection.
  • Kidney failure in people with liver disease (hepatorenal syndrome). Early research suggests that injecting N-acetyl cysteine intravenously (by IV) might improve kidney function in people with hepatorenal syndrome.
  • A blood disorder called hereditary hemorrhagic telangiectasia (HHT). Early research suggests that taking N-acetyl cysteine decreases the number and severity of nosebleeds during the day in people with HHT. However, it doesn’t seem to reduce the number of nighttime nosebleeds.
  • Infertility. Taking N-acetyl cysteine by mouth seems to improve sperm concentration but not sperm movement in infertile men. In women with fertility problems who are taking the fertility drug clomiphene citrate, taking N-acetyl cysteine by mouth does not seem to improve pregnancy rate or miscarriage rate.
  • A skin disease called lamellar ichthyosis. Applying N-acetyl cysteine to the skin might help treat lamellar ichthyosis.
  • Malaria. Early research suggests that injecting N-acetyl cysteine intravenously (by IV) along with the antimalarial drug artesunate does not reduce symptoms or prevent death in people with severe malaria.
  • Miscarriage. Early research suggests that taking N-acetyl cysteine by mouth along with folic acid helps prevent early miscarriages in women with a history of multiple early miscarriages compared to taking only folic acid.
  • Nerve problems caused by oxaliplatin. Early research suggests that taking N-acetyl cysteine by mouth reduces the risk of nerve damage in people receiving oxaliplatin, a drug used to treat certain types of cancer.
  • Polycystic ovarian syndrome (PCOS). Early research suggests that taking N-acetyl cysteine by mouth increases insulin sensitivity in people with high levels of insulin and PCOS. However, it doesn’t seem to improve pre-meal blood sugar or insulin levels. Taking N-acetyl cysteine by mouth along with the fertility drug clomiphene citrate also seems to improve ovulation rates and pregnancy rates in women with PCOS for whom the fertility drug clomiphene citrate doesn’t work. However, metformin seems to improve ovulation rates in these women better than N-acetyl cysteine.
  • Preterm labor. Taking N-acetyl cysteine by mouth along with a certain steroid hormone beginning at 16-18 weeks pregnancy and continuing until labor seems to help prevent preterm labor better than taking the steroid hormone alone. However, taking N-acetyl cysteine by mouth beginning at 25-33 weeks pregnancy and continuing until labor does not seem to improve preterm delivery rates in women with severe high blood pressure during pregnancy (pre-eclampsia) or HELLP syndrome.
  • Schizophrenia. Taking N-acetyl cysteine by mouth for 6 months seems to reduce symptom severity in people with schizophrenia. However, taking N-acetyl cysteine for only 2 months doesn’t seem to work.
  • Septic shock. Injecting N-acetyl cysteine intravenously (by IV) might help improve the ability to breathe in people with septic shock. However, it doesn’t seem to help prevent death due to septic shock.
  • An autoimmune disorder called Sjogren's syndrome. Taking N-acetyl cysteine by mouth might reduce eye soreness and irritation, bad breath, and daytime thirst in people with this condition. However, it doesn’t seem to reduce eye dryness based on clinical evaluation.
  • Ulcerative colitis. Early research suggests that taking N-acetyl cysteine by mouth doesn’t help prevent flare-ups in people with ulcerative colitis who are taking the anti-inflammatory drug mesalamine.
  • Carbon monoxide poisoning.
  • Allergic reactions to phenytoin (Dilantin).
  • Ear infections.
  • Hay fever.
  • Removing heavy metals such as mercury, lead, and cadmium from the body.
  • Chronic fatigue syndrome (CFS).
  • Preventing alcoholic liver damage.
  • Protecting against environmental pollutants.
  • Other conditions.
More evidence is needed to rate the effectiveness of N-acetyl cysteine for these uses.


N-ACETYL CYSTEINE Side Effects & Safety

N-acetyl cysteine is LIKELY SAFE for most adults, when used as a prescription medication. It can cause nausea, vomiting, and diarrhea or constipation. Rarely, it can cause rashes, fever, headache, drowsiness, low blood pressure, and liver problems.

When inhaled (breathed into the lungs), it can also cause swelling in the mouth, runny nose, drowsiness, clamminess, and chest tightness.

N-acetyl cysteine has an unpleasant odor that may make it hard to take.

Special Precautions & Warnings:

Pregnancy or breast-feeding: N-acetyl cysteine is POSSIBLY SAFE when taken by mouth, delivered through a hole in the windpipe, or breathed in. N-acetyl cysteine crosses the placenta, but there is no evidence so far linking it with harm to the unborn child or mother. However, N-acetyl cysteine should only be used in pregnant women when clearly needed, such as in cases of acetaminophen toxicity.

There is not enough reliable information about the safety of taking N-acetyl cysteine if you are breast-feeding. Stay on the safe side and avoid use.

Allergy: Don’t use N-acetyl cysteine if you are allergic to acetyl cysteine.

Asthma: There is a concern that N-acetyl cysteine might cause bronchospasm in people with asthma if inhaled or taken by mouth or through a tube in the windpipe. If you take N-acetyl cysteine and have asthma, you should be monitored by your healthcare provider.

Bleeding disorder. N-acetyl cysteine might slow blood clotting. There is concern that N-acetyl cysteine might increase the risk of bruising and bleeding in people with bleeding disorders.

Surgery. N-acetyl cysteine might slow blood clotting. This might increase the risk of bleeding during and after surgery. Stop taking N-acetyl cysteine at least 2 weeks before a scheduled surgery.

N-ACETYL CYSTEINE Interactions What is this?

Major Interaction Do not take this combination

  • Nitroglycerin interacts with N-ACETYL CYSTEINE

    Nitroglycerin can dilate blood vessels and increase blood flow. Taking N-acetyl cysteine seems to increase the effects of nitroglycerin. This could cause increased chance of side effects including headache, dizziness, and lightheadedness.


Moderate Interaction Be cautious with this combination

  • Activated charcoal interacts with N-ACETYL CYSTEINE

    Activated charcoal is sometimes used to prevent poisoning in people who take too much acetaminophen and other medications. Activated charcoal can bind up these medications in the stomach and prevent them from being absorbed by the body. Taking N-acetyl cysteine at the same time as activated charcoal might decrease how well it works for preventing poisoning.


N-ACETYL CYSTEINE Dosing

The following doses have been studied in scientific research:

BY MOUTH:

  • For acetaminophen (Tylenol) overdose: at the beginning of treatment, a first high dose of 140 mg/kg of a 5% solution of N-acetyl cysteine is given. The commercially available 10% and 20% solutions may be diluted with water, carbonated, or non-carbonated beverages, and given through a straw to lessen the unpleasant odor of N-acetyl cysteine. Seventeen additional doses of 70 mg/kg as a 5% solution are given every 4 hours, for a total dose of 1330 mg/kg over 72 hours.
  • For chest pain that is not relieved by rest (unstable angina): 600 mg of N-acetyl cysteine three times daily with a nitroglycerin patch.
  • For preventing sudden worsening of chronic bronchitis: doses of 200 mg twice daily, 200 mg three times daily, 300 mg slow-release twice daily, and 600 mg controlled-release twice daily have been used.
  • For treating chronic obstructive pulmonary disease (COPD): 600 mg of N-acetyl cysteine once daily, in addition to standard care, has been used for up to 6 months.
  • For treating a lung condition called fibrosing alveolitis that makes breathing difficult: 600 mg of N-acetyl cysteine 3 times daily.
  • For preventing damage to the bladder due to treatment with a cancer drug called ifosfamide: 1 to 2 grams of N-acetyl cysteine every 6 hours.
  • For reducing levels of homocysteine in the blood: 1.2 grams of N-acetyl cysteine daily.
  • For myoclonus epilepsy: 4-6 grams daily.
  • For reducing flu symptoms: 600 mg twice daily.
  • For reducing the risk of heart attacks and strokes in patients with end-stage kidney disease: 600 mg twice daily.
  • For skin wounds due to hemodialysis treatment: 200 mg four times daily or 600 mg twice daily.
  • For preventing kidney damage associated with the use of iopromide (Ultravist-300) for diagnostic tests: 400 to 600 mg of N-acetyl cysteine twice daily on the day before and on the day of iopromide administration, with IV saline (0.45%) 1 mL/kg body weight per hour for 12 hours before and 12 hours after iopromide administration.
  • For trichotillomania (hair-pulling): N-acetyl cysteine 1200 mg to 2400 mg daily has been used.
INTRAVENOUS:
  • Healthcare providers give N-acetyl cysteine intravenously (by IV) for acetaminophen poisoning.

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This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version. © Therapeutic Research Faculty 2009.

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