Receiving too much acetaminophen can cause liver damage, sometimes serious enough to require liver transplantation or cause death. You might accidentally receive too much acetaminophen if you take acetaminophen by mouth or more than one product that contains acetaminophen while receiving acetaminophen intravenously (into the vein).
IMPORTANT NOTICE
On September 22, 2025, the Food and Drug Administration (FDA), issued a safety warning indicating that taking or receiving acetaminophen while pregnant may be associated with the development of neurological conditions such as Autism Spectrum Disorder (ASD) or Attention Hyperactivity Deficit Disorder (ADHD) in children. Although no evidence to date has been able to show that acetaminophen in pregnancy causes these disorders, some studies have shown an association. Talk to your doctor about the risks and benefits or using acetaminophen during pregnancy.
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.
Are there other uses for this medicine?
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
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.
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 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 side effects can this medicine cause?
Acetaminophen injection may cause side effects.
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 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.