Acetaminophen Injection

WHY is this medicine prescribed?

Acetaminophen injection is used to relieve mild to moderate pain and to reduce fever. Acetaminophen injection is also used in combination with opioid (narcotic) medications to relieve moderate to severe pain. Acetaminophen is in a class of medications called analgesics (pain relievers) and antipyretics (fever reducers). It works by changing the way the body senses pain and by cooling the body.

HOW should this medicine be used?

Acetaminophen injection comes as a solution (liquid) to be injected into a vein over 15 minutes. It is usually given every 4 to 6 hours as needed to relieve pain or reduce fever.

Are there OTHER USES for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before receiving acetaminophen injection,

• tell your doctor or pharmacist if you are allergic to this medication, any part of this medication, or any other medications, foods or substances. Tell your doctor or pharmacist about the allergy and what symptoms you had.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take while taking acetaminophen. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had liver disease. Your doctor will probably tell you not to use acetaminophen injection.
• tell your doctor if you drink or have ever drunk large amounts of alcohol, if you have had severe vomiting or diarrhea or think you may be dehydrated, if you are not able to eat and drink enough to stay healthy, and if you have or have ever had kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while receiving acetaminophen injection, call your doctor.
• ask your doctor or pharmacist about the safe use of alcoholic beverages while receiving acetaminophen injection.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What SIDE EFFECTS can this medicine cause?

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• rash hives; itching; swelling of the face, throat, tongue, lips, eyes, hands, feet or lower legs; hoarseness; difficulty breathing or swallowing
• yellowing of the skin or whites of the eyes; upper belly pain; dark urine; pale stools

Acetaminophen injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

If someone receives too much acetaminophen injection, get medical help immediately, even if the person does not have any symptoms. Symptoms of overdose may include the following:

• nausea, vomiting, loss of appetite, upper belly pain
• sweating
• extreme tiredness or lack of energy; flu-like symptoms
• unusual bleeding or bruising
• yellowing of the skin or eyes
• dark-colored urine
• coma (loss of consciousness)

What OTHER INFORMATION should I know?

Before having any laboratory test, tell your doctor and the laboratory personnel that you are receiving acetaminophen injection.

Ask your pharmacist any questions you have about acetaminophen injection.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™. © Copyright, 2024. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: October 15, 2025.