February 13, 2016
Recommended Topic Related To:


"July 8, 2010 -- The recall of Tylenol and other over-the-counter medicines has grown once again, with Tylenol maker McNeil PCC Inc. today announcing the recall of 21 lots of medicines as a precautionary measure.

Today's recall includes "...





American Hospital Formulary Service (Ahfs)* Classification Number


Generic Name

USAN: acetaminophen

INN: paracetamol CAS#: 103-90-2

Source of Supply (Trade Name and Manufacturer)

TYLENOL® (acetaminophen) - McNeil Consumer Healthcare

Physical Properties Of The Chemical Entity1

a. Structural Formula

Tylenol (acetaminophen) structural formula illustration

b. Molecular Formula


c. Molecular Weight


d. Macroscopic Appearance

Acetaminophen is a white, crystalline powder.

e. Solubility

water 1:70
boiling water 1:20
alcohol 1:10
chloroform 1:50
glycerin 1:40
ether slightly soluble

Chemical Properties

a. Structural Similarities/Differences of the Drug to Other Available Compounds or Groups of Compounds

Acetaminophen is a synthetic, nonopiate, centrally acting analgesic derived from p-aminophenol. The full chemical name is N-acetyl-p-aminophenol.

b. pKa

The pKa of acetaminophen is 9.51 at 25°C.

c. Stability of the Drug to Temperature, Light, and Moisture

Acetaminophen is stable to temperature, light, and moisture.

d. pH Range Over Which Drug is Stable in Solution

Acetaminophen is stable at a pH between 4 and 7 at 25°C.

e. pH of Commercially Available Liquid Products

Acetaminophen oral solution (ie, elixir, adult liquid) has a pH of 3.8 to 6.1 and the oral suspension (ie, infants' drops, children's suspension) has a pH of 5.4 to 6.9.

f. Osmolarity/Osmolality of Commercially Available Solutions

Extra Strength TYLENOL® acetaminophen Adult Liquid: 3058 ± 152 mmol/kg

Children's TYLENOL® acetaminophen Elixir: 6040 ± 25 mmol/kg

Because of the nature of suspension formulations, osmolarity of the TYLENOL® acetaminophen suspension products cannot be determined.


1. Remington's Pharmaceutical Sciences. 23rd ed. Easton, PA: Mack Publishing Company; 1995:1109-1110.

*Permission to use the Product Information Form for the American Hospital Formulary Service as modified by McNeil Consumer Healthcare has been granted by the American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, MD 20814. The answers to all questions are prepared and furnished by the manufacturer. The answers were not supplied by the Society nor are they intended to imply the endorsement of the American Society of Health-System Pharmacists; neither does the Society affirm or deny the accuracy of the answers contained herein. Copyright© 1985, American Society of Health-System Pharmacists, Inc., all rights reserved.

What are the possible side effects of acetaminophen?

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

Stop taking this medication and call your doctor at once if you have a serious side effect such as:

  • nausea, upper stomach pain, itching, loss of appetite;
  • dark urine, clay-colored stools; or
  • jaundice (yellowing of the skin or eyes).

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...

Read All Potential Side Effects and See Pictures of Tylenol »

What are the precautions when taking acetaminophen (Tylenol)?

See also Warning section.

Before taking acetaminophen, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this product, tell your doctor or pharmacist your medical history, especially of: liver disease, regular use/abuse of alcohol.

Liquid products, chewable tablets, or dissolving/effervescent tablets may contain sugar or aspartame. Caution is advised if you have diabetes, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. If you have any of these conditions, ask your doctor or pharmacist about using these...

Read All Potential Precautions of Tylenol »

Last reviewed on RxList: 11/7/2007
This monograph has been modified to include the generic and brand name in many instances.

Tylenol - User Reviews

Tylenol User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Tylenol sorted by most helpful. Patient Discussions FAQs

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Chronic Pain/Back Pain

Find tips and advances in treatment.