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Acetaminophen

Acetaminophen

Definition

Acetaminophen is a medicine used to relieve pain and reduce fever.


Purpose

Acetaminophen is used to relieve many kinds of minor aches and pains, including headaches, muscle aches, backaches, toothaches, menstrual cramps, arthritis, and the aches and pains that often accompany colds. It is suitable for control of pain following minor surgery, or for post-surgical pain after the need for stronger pain relievers has been reduced. Acetaminophen is also used in combination with narcotic analgesics both to increase pain relief and reduce the risk that the narcotics will be abused.


Description

This drug is available without a prescription. Acetaminophen (APAP) is sold under various brand names, including Tylenol, Panadol, Aspirin-Free Anacin, and Bayer Select Maximum Strength Headache Pain Relief Formula. Many multi-symptom cold, flu, and sinus medicines also contain acetaminophen. Persons are advised to check the ingredients listed on the container to see if acetaminophen is included in the product.

Acetaminophen is also included in some prescription-only combinations. These usually contain a narcotic in addition to acetaminophen; it is combined with oxycodone in Percocet, and is included in Tylenol with Codeine.

Studies have shown that acetaminophen relieves pain and reduces fever about as well as aspirin . But differences between these two common drugs exist. Acetaminophen is less likely than aspirin to irritate the stomach. However, unlike aspirin, acetaminophen does not reduce the redness, stiffness, or swelling that accompany arthritis.

Recommended dosage

The usual dosage for adults and children age 12 and over is 325650 mg every four to six hours as needed. No more than 4 g (4,000 mg) should be taken in 24 hours. Because the drug can potentially harm the liver, people who drink alcohol in large quantities should take considerably less acetaminophen and possibly should avoid the drug completely.

For children ages six to 11 years, the usual dose is 150300 mg, three to four times a day. People are advised to check with a physician for dosages for children under six years of age.


Precautions

A person should never take more than the recommended dosage of acetaminophen unless told to do so by a physician or dentist.

Because acetaminophen is included in both prescription and non-prescription combinations, it is important to check the total amount of acetaminophen taken each day from all sources in order to avoid taking more than the recommended maximum dose.

Patients should not use acetaminophen for more than 10 days to relieve pain (five days for children) or for more than three days to reduce fever, unless directed to do so by a physician. If symptoms do not go away, or if they get worse, the patient should contact a physician. Anyone who drinks three or more alcoholic beverages a day should check with a physician before using this drug and should never take more than the recommended dosage. People who already have kidney or liver disease or liver infections should also consult with a physician before using the drug. Women who are pregnant or breastfeeding should also consult with a physician before using acetaminophen.

Smoking cigarettes may interfere with the effectiveness of acetaminophen. Smokers may need to take higher doses of the medicine, but should not take more than the recommended daily dosage unless told to do so by a physician.

Many drugs can interact with one another. People should consult a physician or pharmacist before combining acetaminophen with any other medicine, and they should not use two different acetaminophen-containing products at the same time, unless instructed by a physician or dentist.

Some products, such as Nyquil, contain acetaminophen in combination with alcohol. While these products are safe for people who do not drink alcoholic beverages, people who consume alcoholic drinks regularly, even in moderation, should use extra care before using acetaminophen-alcohol combinations.

Acetaminophen interferes with the results of some medical tests. Before having medical tests done, a person should check to see whether taking acetaminophen would affect the results. Avoiding the drug for a few days before the tests may be necessary.


Side effects

Acetaminophen causes few side effects. The most common one is lightheadedness. Some people may experience trembling and pain in the side or the lower back. Allergic reactions do occur in some people, but they are rare. Anyone who develops symptoms such as rash, swelling, or difficulty breathing after taking acetaminophen should stop taking the drug and get immediate medical attention. Other rare side effects include yellow skin or eyes, unusual bleeding or bruising, weakness, fatigue, bloody or black stools, bloody or cloudy urine, and a sudden decrease in the amount of urine.

Overdoses of acetaminophen may cause nausea, vomiting, sweating, and exhaustion. Very large overdoses can cause liver damage. In case of an overdose, a person is advised to get immediate medical attention.


Interactions

Acetaminophen may interact with a variety of other medicines. When this happens, the effects of one or both of the drugs may change or the risk of side effects may be greater. Among the drugs that may interact with acetaminophen are alcohol, non-steroidal anti-inflammatory drugs (NSAIDs) such as Motrin, oral contraceptives, the anti-seizure drug phenytoin (Dilantin), the blood-thinning drug warfarin (Coumadin), the cholesterol-lowering drug cholestyramine (Questran), the antibiotic Isoniazid, and zidovudine (Retrovir, AZT). People should check with a physician or pharmacist before combining acetaminophen with any other prescription or nonprescription (over-the-counter) medicine.


Resources

books

Brody, T.M., J. Larner, K.P. Minneman, and H.C. Neu. Human Pharmacology: Molecular to Clinical, 2nd ed. St. Louis: Mosby Year-Book, 1998.

Griffith, H.W., and S. Moore. 2001 Complete Guide to Prescription and Nonprescription Drugs. New York: Berkely Publishing Group, 2001.


other

"Acetaminophen." Federal Drug Administration. Center for Drug Evaluation and Research. [cited May 2003] <http://www.fda.gov/cder/foi/nda/2000/75077_Acetaminophen.pdf>.

"Acetaminophen." Medline Plus Drug Information. [cited May 2003] <http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a681004.html>.

"Acetaminophen, Systemic." Medline Plus Drug Information. [cited May 2003] <http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202001.html>.


Nancy Ross-Flanigan Sam Uretsky

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"Acetaminophen." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

"Acetaminophen." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. . Encyclopedia.com. (August 19, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/acetaminophen-0

"Acetaminophen." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/acetaminophen-0

Acetaminophen

Acetaminophen

Definition

Acetaminophen is a medicine used to relieve pain and reduce fever .

Description

Acetaminophen is used to relieve many kinds of minor aches and pains: headaches, muscle aches, backaches, toothaches, menstrual cramps, arthritis, and the aches and pains that often accompany colds.

Description

This drug is available without a prescription. Acetaminophen is sold under various brand names, including Tylenol, Panadol, Aspirin Free Anacin, and Bayer Select Maximum Strength Headache Pain Relief Formula. Many multi-symptom cold, flu, and sinus medicines also contain acetaminophen.

Studies have shown that acetaminophen relieves pain and reduces fever about as well as aspirin. But differences between these two common drugs exist. Acetaminophen is less likely than aspirin to irritate the stomach. However, unlike aspirin, acetaminophen does not reduce the redness, stiffness, or swelling that accompany arthritis.

Precautions

Most of the precautions for acetaminophen apply to adults rather than children but may apply to some teenagers.

The primary precaution in children's therapy is to watch the dosage carefully and follow the label instructions only. Acetaminophen for children comes in two strengths. Children's acetaminophen contains low concentrations of the drug, 160 milligrams in a teaspoonful of solution. The infant drops contain a much higher concentration of acetaminophen, 100 milligrams in 20 drops, equal to 500 milligrams in a teaspoonful. The infant drops should never be given by the teaspoonful.

Parents should never give their child more than the recommended dosage of acetaminophen unless told to do so by a physician or dentist.

Patients should not use acetaminophen for more than 10 days to relieve pain (five days for children) or for more than three days to reduce fever, unless directed to do so by a physician. If symptoms do not go away or if they get worse, a physician should be contacted. Anyone who drinks three or more alcoholic beverages a day should check with a physician before using this drug and should never take more than the recommended dosage. A risk of liver damage exists from combining large amounts of alcohol and acetaminophen. People who already have kidney or liver disease or liver infections should also consult with a physician before using the drug. Women who are pregnant or breastfeeding should do the same.

Side effects

Acetaminophen causes few side effects. The most common one is lightheadedness. Some people may experience trembling and pain in the side or the lower back. Allergic reactions do occur in some people, but they are rare. Anyone who develops symptoms such as a rash, swelling, or difficulty breathing after taking acetaminophen should stop taking the drug and get immediate medical attention. Other rare side effects include yellow skin or eyes, unusual bleeding or bruising, weakness, fatigue, bloody or black stools, bloody or cloudy urine, and a sudden decrease in the amount of urine.

Overdoses of acetaminophen may cause nausea, vomiting , sweating, and exhaustion. Very large overdoses can cause liver damage. In case of an overdose, parents should get immediate medical attention for their child.

Interactions

Acetaminophen may interact with a variety of other medicines. When this happens, the effects of one or both of the drugs may change or the risk of side effects may be greater. Among the drugs that may interact with acetaminophen are the following:

  • alcohol
  • nonsteroidal anti-inflammatory drugs (NSAIDs) such as Motrin
  • oral contraceptives
  • the antiseizure drug phenytoin (Dilantin)
  • the blood-thinning drug warfarin (Coumadin)
  • the cholesterol-lowering drug cholestyramine (Questran)
  • the antibiotic Isoniazid
  • zidovudine (Retrovir, AZT)

Check with a physician or pharmacist before combining acetaminophen with any other prescription or nonprescription (over-the-counter) medicine.

Acetaminophen is generally safe when taken as directed. Acetaminophen is commonly mixed with other ingredients as part of combinations intended for colds, influenza , and other conditions. Parents should read the labels carefully in order to avoid giving an overdose of acetaminophen to their child. They need to be particularly cautious about liquid medicines that contain acetaminophen and alcohol.

Parental concerns

Acetaminophen is very safe when used properly. While most precautions are intended to reduce the risk of overdose, parents should not try to reduce the risk by giving a lower than normal dose. Children should not suffer pain if it can be safely treated.

See also Analgesics; Pain management.

Resources

BOOKS

Beers, Mark H., and Robert Berkow, eds. The Merck Manual, 2nd home ed. West Point, PA: Merck & Co., 2004.

Mcevoy, Gerald, et al. AHFS Drug Information 2004. Bethesda, MD: American Society of Healthsystems Pharmacists, 2004.

Siberry, George K., and Robert Iannone, eds. The Harriet Lane Handbook, 15th ed. Philadelphia: Mosby Publishing, 2000.

PERIODICALS

Burillo-Putze G., et al. "Changes in pediatric toxic dose of acetaminophen." American Journal of Emergency Medicine 22, no. 4 (July 2004): 323.

Evered, L. M. "Evidence-based emergency medicine/systematic review abstract. Does acetaminophen treat fever in children?" American Journal of Emergency Medicine 41, no. 5 (May 2003): 7413.

Goldman, Ran D., and D. Scolnik. "Underdosing of acetaminophen by parents and emergency department utilization." Pediatric Emergency Care 20, no. 2 (February 2004): 8993.

Kociancic T., et al. "Acetaminophen intoxication and length of treatment: how long is long enough?" Pharmacotherapy 23, no. 8 (August 2003): 10529.

Losek, Joseph D. "Acetaminophen dose accuracy and pediatric emergency care." Pediatric Emergency Care 20, no. 5 (May 2004): 2858.

ORGANIZATIONS

American Pain Society. 4700 W. Lake Ave., Glenview, IL 60025. Web site: <www.ampainsoc.org/>.

WEB SITES

"Acetaminophen." MedlinePlus. Available online at

<www.nlm.nih.gov/medlineplus/druginfo/medmaster/a681004.html> (accessed October 15, 2004).

Nancy Ross-Flanigan Samuel Uretsky, PharmD

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"Acetaminophen." Gale Encyclopedia of Children's Health: Infancy through Adolescence. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

"Acetaminophen." Gale Encyclopedia of Children's Health: Infancy through Adolescence. . Encyclopedia.com. (August 19, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/acetaminophen-1

"Acetaminophen." Gale Encyclopedia of Children's Health: Infancy through Adolescence. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/acetaminophen-1

Acetaminophen

Acetaminophen

Definition

Acetaminophen is a medicine used to relieve pain and reduce fever.

Purpose

Acetaminophen is used to relieve many kinds of minor aches and painsheadaches, muscle aches, backaches, toothaches, menstrual cramps, arthritis, and the aches and pains that often accompany colds.

Description

This drug is available without a prescription. Acetaminophen is sold under various brand names, including Tylenol, Panadol, Aspirin Free Anacin, and Bayer Select Maximum Strength Headache Pain Relief Formula. Many multi-symptom cold, flu, and sinus medicines also contain acetaminophen. The ingredients listing on the container should state if acetaminophen is included in the product.

Studies have shown that acetaminophen relieves pain and reduces fever about as well as aspirin. But differences between these two common drugs exist. Acetaminophen is less likely than aspirin to irritate the stomach. However, unlike aspirin, acetaminophen does not reduce the redness, stiffness, or swelling that accompany arthritis.

Recommended dosage

The usual dosage for adults and children age 12 and over is 325-650 mg every four to six hours as needed. No more than 4 grams (4000 mg) should be taken in 24 hours. Because the drug can potentially harm the liver, people who drink alcohol in large quantities should take considerably less acetaminophen and possibly should avoid the drug completely.

For children ages 6-11 years, the usual dose is 150-300 mg, three to four times a day. A physician should recommend doses for children under age 6 years.

Precautions

In 2004, the U.S. Food and Drug Administration (FDA) launched an advertising campaign aimed at educating consumers about proper use of acetaminophen and other over-the-counter pain killers. Often, acetaminophen is hidden in many cold and flu products and people unexpectedly overdose on the medicine. Some cases have led to liver transplantation or death. More than the recommended dosage of acetaminophen should not be taken unless told to do so by a physician or dentist.

Patients should not use acetaminophen for more than 10 days to relieve pain (five days for children) or for more than three days to reduce fever, unless directed to do so by a physician. If symptoms do not go awayor if they get worsea physician should be contacted. Anyone who drinks three or more alcoholic beverages a day should check with a physician before using this drug and should never take more than the recommended dosage. A risk of liver damage exists from combining large amounts of alcohol and acetaminophen. People who already have kidney or liver disease or liver infections should also consult with a physician before using the drug. So should women who are pregnant or breastfeeding.

Many drugs can interact with one another. A physician or pharmacist should be consulted before combining acetaminophen with any other medicine. Two different acetaminophen-containing products should not be used at the same time.

Acetaminophen interferes with the results of some medical tests. Avoiding the drug for a few days before the tests may be necessary.

Side effects

Acetaminophen causes few side effects. The most common one is lightheadedness. Some people may experience trembling and pain in the side or the lower back. Allergic reactions occur in some people, but are rare. Anyone who develops symptoms such as a rash, swelling, or difficulty breathing after taking acetaminophen should stop taking the drug and get immediate medical attention. Other rare side effects include yellow skin or eyes, unusual bleeding or bruising, weakness, fatigue, bloody or black stools, bloody or cloudy urine, and a sudden decrease in the amount of urine.

Overdoses of acetaminophen may cause nausea, vomiting, sweating, and exhaustion. Very large overdoses can cause liver damage. In case of an overdose, immediate medical attention should be sought. In 2004, researchers announced that an injection to counteract the liver injury caused by acetaminophen overdose has been approved by the FDA.

KEY TERMS

Arthritis Inflammation of the joints. The condition causes pain and swelling.

Fatigue Physical or mental weariness.

Inflammation A response to irritation, infection, or injury, resulting in pain, redness, and swelling.

Interactions

Acetaminophen may interact with a variety of other medicines. When this happens, the effects of one or both of the drugs may change or the risk of side effects may be greater. Among the drugs that may interact with acetaminophen are alcohol, nonsteroidal anti-inflammatory drugs (NSAIDs) such as Motrin, oral contraceptives, the antiseizure drug phenytoin (Dilantin), the blood-thinning drug warfarin (Coumadin), the cholesterol-lowering drug cholestyramine (Questran), the antibiotic Isoniazid, and zidovudine (Retrovir, AZT). A physician or pharmacist should be consulted before combining acetaminophen with any other prescription or nonprescription (over-the-counter) medicine.

Resources

PERIODICALS

"Antidote Cleared for Acetiminophen Overdose." Drug Topics February 23, 2004: 12.

Mechcatie, Elizabeth. "FDA Launches Campaign About OTC Drug Risks: NSAIDs, Acetaminophen." Family Practice News March 15, 2004: 81

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Acetaminophen

Acetaminophen


The drug acetaminophen is a pain reliever (an analgesic ) and a fever-reducing agent (an antipyretic). It is found in over-the-counter medicines such as Tylenol and Excedrin. It is widely used to treat both chronic and acute pain and is considered to have a pain-relieving potency similar to that of other over-the-counter analgesics, such as aspirin and ibuprofen. Its chemical name is 4-hydroxyacetanalide. Its chemical formula is C8H9NO2 (see Figure 1).

Acetaminophen was used as a pain reliever as early as the late 1800s. It was approved for use by the U.S. Food and Drug Administration in 1950, shortly after it was discovered that the closely related drug paracetin was broken down in the body to acetaminophen, and that the beneficial effects of paracetin were actually the effects of acetaminophen.

Acetaminophen works by inhibiting the synthesis of chemical messengers called prostaglandins, which help to transmit pain signals and induce fever. The body produces prostaglandins in response to an injury or illness. Acetaminophen reduces the pain by helping to block this signaling. Acetaminophen stops some prostaglandin functions while not affecting others. Prostaglandins are known to promote inflammation and swelling of many body tissues. Unlike aspirin and ibuprofen, acetaminophen does not have anti-inflammatory action.

The differences in the actions of these drugs involve their tissue specificities. Aspirin and ibuprofen act on a broad range of tissues. Acetaminophen inhibits prostaglandin synthesis more specifically in the cells of the nervous system and is a much less effective inhibitor of this in other tissues. This selectivity gives acetaminophen its analgesic and antipyretic effects without acetaminophen's acting as an anti-inflammatory drug.

Acetaminophen is known to cause less stomach irritation than aspirin and ibuprofen, and it does not inhibit platelet aggregation and blood clotting (as does aspirin).

When given in its therapeutic dose (500 mg every 46 hours), acetaminophen is a safe and effective pain reliever. However, at higher doses it can be severely toxic to the liver, and even fatal.

The drug itself is not toxic, but a toxic compound, N-acetyl-p -benzoquinonimine, is formed from it as it is broken down by enzymes in the liver. In small amounts this compound can be detoxified and excreted . But in large amounts it overwhelms the detoxification system and the compound begins killing liver tissue. Overdose can be treated by giving the patient activated charcoal, which absorbs the acetaminophen in the patient's stomach and intestines, and by administering N -acetylcystine, a compound that can deactivate the toxic product of metabolism .

see also Acetylsalicylic Acid; Ibuprofen.

Kyle Knight

Bibliography

Devlin, Thomas M., ed. (2002). Textbook of Biochemistry: With Clinical Correlations, 5th edition. New York: Wiley-Liss.

Nelson, David L.; and Cox, Michael M. (2000). Lehninger Principles of Biochemistry, 3rd edition. New York: Worth Publishers.

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"Acetaminophen." Chemistry: Foundations and Applications. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/news-wires-white-papers-and-books/acetaminophen

acetaminophen

acetaminophen (əsēt´əmĬn´əfĬn), an analgesic and fever-reducing medicine. It is an active ingredient in many over-the-counter medicines, including Tylenol and Midol. Introduced in the early 1900s, acetaminophen is a coal tar derivative that acts by interfering with the synthesis of prostaglandins and other substances necessary for the transmission of pain impulses. Although its action is similar to that of aspirin, it lacks aspirin's anti-inflammatory and blood-thinning effects, is less irritating to the stomach, and can be used by people who are allergic to aspirin. Heavy use, however, has been linked to an increased incidence of liver failure, especially in heavy drinkers of alcoholic beverages and in those who are not eating enough, and overdose, especially in children, can be fatal.

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"acetaminophen." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

"acetaminophen." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (August 19, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/acetaminophen

"acetaminophen." The Columbia Encyclopedia, 6th ed.. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/acetaminophen

acetaminophen

a·ce·ta·min·o·phen / əˌsētəˈminəfən/ • n. an analgesic drug, C8H9NO2, used to treat headaches, arthritis, etc., and also to reduce fever.

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"acetaminophen." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

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"acetaminophen." The Oxford Pocket Dictionary of Current English. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/acetaminophen

acetaminophen

acetaminophen (ass-ee-tă-min-ŏ-fen) n. see paracetamol.

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