Generic name: acetaminophen (injection) [ a-SEET-a-MIN-oh-FEN ]
Brand name: Ofirmev
Dosage form: intravenous solution (10 mg/mL)
Drug class: Miscellaneous analgesics

Medically reviewed by Drugs.com on Jul 14, 2021. Written by Cerner Multum.

What is acetaminophen injection?

Acetaminophen injection is used to treat pain in adults and children at least 2 years old. For moderate to severe pain, acetaminophen is sometimes given with opioid pain medicine.

Acetaminophen injection may also be used for purposes not listed in this medication guide.

Warnings

Call your doctor at once if you have nausea, vomiting, upper stomach pain, and yellowing of your skin or eyes.

In rare cases, acetaminophen may cause a severe skin reaction that can be fatal. Call your doctor right away if you have skin redness or a rash that spreads and causes blistering and peeling.

Before taking this medicine

You should not be treated with acetaminophen if you are allergic to it or if you have severe liver disease.

Tell your doctor if you have ever had:

• bleeding problems;

• liver disease, cirrhosis, alcoholism, or more than 3 alcoholic beverages per day;

• kidney disease; or

• if you''ve recently been sick with vomiting or diarrhea;

• if you are malnourished.

Tell your doctor if you are pregnant or breastfeeding.

Pregnancy may be less likely to occur while the mother or the father is using acetaminophen.

How is acetaminophen injection given?

Acetaminophen is injected into a vein by a healthcare provider, usually once every 4 to 6 hours.

Doses are based on weight in people who weigh under 110 pounds (50 kilograms). If you use this medicine long term, your dose may change if you gain or lose weight.

What happens if I miss a dose?

In a medical setting you are not likely to miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose can be fatal.

Overdose symptoms include vomiting, stomach pain, and yellowing of your skin or eyes.

What should I avoid while using acetaminophen injection?

Avoid using other medicines that may contain acetaminophen (sometimes abbreviated as APAP).

Drinking alcohol may increase your risk of liver damage.

Acetaminophen injection side effects

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

In rare cases, acetaminophen may cause a severe skin reaction that can be fatal, even if you took acetaminophen in the past and had no reaction. Tell your caregivers or call your doctor if you have skin redness or a rash that spreads and causes blistering and peeling.

Acetaminophen may cause serious side effects. Stop using acetaminophen and call your doctor at once if you have:

• fever, cough, chest pain, trouble breathing; or

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

Common side effects of acetaminophen may include:

• cough, breathing problems;

• nausea, vomiting;

• constipation;

• agitation;

• itching;

• headache; or

• sleep problems (insomnia).

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 1-800-FDA-1088.

What other drugs will affect acetaminophen injection?

Tell your doctor if you also use a blood thinner (warfarin, Coumadin, Jantoven)

Other drugs may affect acetaminophen, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Where can I get more information?

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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Copyright 1996-2023 Cerner Multum, Inc. Version: 4.01.

Medically reviewed by Drugs.com. Last updated on Dec 25, 2022.

Commonly used brand name(s)

In the U.S.

• Ofirmev

Available Dosage Forms:

• Solution

Therapeutic Class: Analgesic

Uses for acetaminophen

Acetaminophen injection is used together with other medicines (eg, narcotic pain relievers) to relieve moderate to severe pain.

Acetaminophen is used to relieve mild to moderate pain and reduce fever in patients. It does not become habit-forming when taken for a long time. Acetaminophen may cause unwanted effects when taken in large doses, including liver damage.

Acetaminophen is available only with your doctor''s prescription.

Before using acetaminophen

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For acetaminophen, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to acetaminophen or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of acetaminophen injection for the treatment of acute pain in children 2 years of age and older. However, safety and efficacy have not been established in children younger than 2 years of age.

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of acetaminophen injection for the treatment of fever in children and premature infants 32 weeks of age and older. However, safety and efficacy have not been established in children and premature infants younger than 32 weeks of age.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of acetaminophen injection in the elderly.

Breastfeeding

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Interactions with medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving acetaminophen, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using acetaminophen with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Imatinib
• Isoniazid
• Pixantrone
• Pneumococcal 13-Valent Vaccine, Diphtheria Conjugate

Using acetaminophen with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Acenocoumarol
• Carbamazepine
• Fosphenytoin
• Lixisenatide
• Phenytoin
• Warfarin
• Zidovudine

Interactions with food/tobacco/alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using acetaminophen with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use acetaminophen, or give you special instructions about the use of food, alcohol, or tobacco.

• Ethanol
• Tobacco

Using acetaminophen with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use acetaminophen, or give you special instructions about the use of food, alcohol, or tobacco.

• Cabbage

Other medical problems

The presence of other medical problems may affect the use of acetaminophen. Make sure you tell your doctor if you have any other medical problems, especially:

• Alcohol abuse, history of or
• Hypovolemia (low blood volume), severe or
• Kidney disease, severe or
• Liver disease or
• Malnourished condition—Use with caution. May increase risk for more serious side effects.

• Liver disease, active and severe—Should not be used in patients with this condition.

Proper use of acetaminophen

A nurse or other trained health professional will give you acetaminophen. Acetaminophen is given through a needle placed in one of your veins. The medicine must be injected slowly over 15 minutes.

Your doctor will give you a few doses of acetaminophen until your condition improves, and then switch you to an oral medicine that works the same way. If you have any concerns about this, talk to your doctor.

Precautions while using acetaminophen

It is very important that your doctor check you closely while you or your child are receiving acetaminophen. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it.

Check with your doctor right away if you or your child have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, unusual tiredness or weakness, or yellow eyes or skin. These could be symptoms of a serious liver problem.

Acetaminophen may cause serious types of allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you or your child have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth after you receive acetaminophen.

Serious skin reactions can occur with acetaminophen. Check with your doctor right away if you have blistering, peeling, or loose skin, red skin lesions, severe acne or skin rash, sores or ulcers on the skin, or fever or chills while you or your child are receiving acetaminophen.

Acetaminophen will add to the effects of alcohol and other CNS depressants (medicines that can make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicine, other prescription pain medicine or narcotics, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics. Also, there may be a greater risk of liver damage if you drink three or more alcoholic beverages while you are taking acetaminophen. Do not drink alcoholic beverages, and check with your doctor before taking any of these medicines while you or your child are using acetaminophen.

Carefully check the labels of all other medicines you are using, because they may also contain acetaminophen (eg, Tylenol®). It is not safe to use more than 4 grams (4,000 milligrams) of acetaminophen in one day (24 hours).

Acetaminophen side effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

Less common-Adults

• Abnormal breath sounds
• bloating or swelling of the face, arms, hands, lower legs, or feet
• difficult or labored breathing
• difficulty opening the mouth
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• irregular heartbeat
• lockjaw
• loss of appetite
• muscle pain or cramps
• muscle spasm, especially of the neck and back
• nausea or vomiting
• nervousness
• numbness or tingling in the hands, feet, or lips
• pain at the injection site
• slow or fast heartbeat
• sweating
• tightness in the chest
• unusual tiredness or weakness

Less common-Children

• Decreased urination
• difficult, fast, or noisy breathing, sometimes with wheezing
• dizziness
• fast, slow, pounding, or irregular heartbeat or pulse
• lower back, side, or stomach pain
• muscle spasms (tetany) or twitching
• noisy breathing
• pain in the arms or legs
• swelling around the eyes
• swelling of the feet, ankles, or lower legs

Incidence not known

• Abdominal or stomach pain or tenderness
• clay colored stools
• dark urine
• decreased appetite
• difficulty with swallowing
• flu-like symptoms
• loss of appetite
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• right upper stomach tenderness
• skin rash, itching, or hives
• tightness in the chest
• yellow eyes or skin

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose

• Black, tarry stools
• bleeding gums
• bloating of the abdomen or stomach
• blood in the urine or stools
• chills
• difficult or painful urination
• general feeling of discomfort or illness
• light-colored stools
• pinpoint red spots on the skin
• sudden decrease in the amount of urine
• unpleasant breath odor
• vomiting of blood

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Trouble sleeping

Less common-Adults

• Fear

Less common-Children

• Diarrhea
• difficulty having a bowel movement (stool)
• irritability
• restlessness

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Frequently asked questions

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer