Acetaminophen

OVERVIEW

Acetaminophen (uh-SEE-toe-Min-oh-fen) is one of the most commonly used analgesics in the world. It is also known as p-Acetylaminophenol; p-acetamidophenol; N-acetyl-p-aminophenol; p-hydroxyacetanilide; and paracetamol. It is an ingredient in more than 100 commercial products including Abensanil®, Acamol®, Acetagesic®, Alpinyl®, Alvedon®, Anaflon®, Anelix®, Anhiba®, Calpol®, Datril®, Dirox®, Doliprane®, Dymadon®, Enelfa®, Eneril®, Exdol®, Febrilix®, Febrolin®, Fendon®, Finimal®, Hedex®, Homoolan®, Lonarid®, Multin®, Panadol®, Phendon®, Tylenol®, Valdol®, and Valgesic®. Acetaminophen is often combined with other ingredients in medications such as cold and flu products, cough suppressants, and allergy medications in order to treat more than one symptom at a time.

KEY FACTS

OTHER NAMES:

See Overview.

FORMULA:

CH₃CONHC₆H₄OH

ELEMENTS:

Carbon, hydrogen, oxygen, nitrogen

COMPOUND TYPE:

Aromatic amide (organic)

STATE:

Solid

MOLECULAR WEIGHT:

151.16 g/mol

MELTING POINT:

169°C-172°C (336°F-342°F)

BOILING POINT:

Not applicable (decomposes)

SOLUBILITY:

Insoluble in cold water; more soluble in warm water; soluble in alcohol, acetone, and other organic solvents

Acetaminophen was first discovered in 1852 by the French chemist Charles Frederic Gerhardt, who also discovered aspirin a year later. His results were largely ignored, however, until a German chemist, Harmon Northrop Morse (1848–1920) re-discovered and synthesized the compound in 1873. Even then, the medicinal qualities of the compound were not appreciated for another twenty years, and the compound was not even prescribed or used by doctors until 1949. Since that time, however, it has become extremely popular, exceeded only by aspirin as the most popular analgesic sold in the world.

HOW IT IS MADE

Acetaminophen is made in a straight-forward reaction between p-aminophenol [C₆H₄(OH)(NH₂)] and acetic anhydride [(CH₃CO)₂O]. As its formula shows, the p-aminophenol provides the basic structure from which acetaminophen is formed, with the acetic anhydride adding the -CH₃CO group of atoms needed to complete the compound.

COMMON USES AND POTENTIAL HAZARDS

In addition to its use as a pain reliever, acetaminophen has a number of industrial uses, including:

• Stabilizer for hydrogen peroxide solutions, to prevent the peroxide from breaking down too quickly;
• Raw material in the production of other pharmaceutical compounds;
• Raw material in the manufacture of photographic chemicals; and
• Raw material in the production of azo dyes, dyes that contain nitrogen atoms at the core of their molecules

Interesting Facts

In September 1982, seven individuals in the Chicago area died after taking a form of Tylenol® called Extra Strength Tylenol®. Officials later found that someone had added cyanide to the Tylenol® bottles. It was the poison and not the pain-killer that had caused the deaths. The crime was never solved, but it led to the introduction of so-called tamper proof packaging for virtually all medicines.

Words to Know

ANALGESIC

A substance that relieves pain.

SYNTHESIS

A chemical reaction in which some desired chemical product is made from simple beginning chemicals, or reactants.

Acetaminophen is generally regarded as so safe that anyone can purchase it without a prescription. The drug is not entirely without its hazards, however. People who take large quantities of acetaminophen are at some risk for liver damage. That risk is especially great for anyone who drinks excessive amounts of alcohol. Alcohol by itself damages the liver and, in conjunction with acetaminophen, that damage can be serious. Some manufacturers now include a message on the labels of their acetaminophen bottles about the risk of excessive ingestion of alcohol and acetaminophen.

FOR FURTHER INFORMATION

Kaplan, Tamara. "The Tylenol Crisis: How Effective Public Relations Saved Johnson &Johnson." http://www.personal.psu.edu/users/w/x/wxk116/tylenol/crisis.html (accessed on September 14, 2005).

Keenan, Faith. "Blocking Liver Damage." Business Week (October 21, 2002): 147.

MedlinePlus Drug Information, Acetaminophen. http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a681004.html (accessed on September 15, 2005).

Paracetamol Information Center. http://www.pharmweb.net/pwmirror/pwy/paracetamol/pharmwebpic.html (accessed on September 15, 2005).