Generic name: acetaminophen [ a-seet-a-MIN-oh-fen ]
Drug class: Miscellaneous analgesics
Medically reviewed by Drugs.com. Last updated on Feb 4, 2023.
Prevent acetaminophen injection dosing errors, which may result in accidental overdose and death, by confirming that doses in milligrams (mg) are not confused with doses in milliliters (mL); that patients under 50 kg receive weight-based doses; that infusion pumps are programmed correctly; and that the total dose of acetaminophen from all routes and from all sources does not exceed daily limits. Life-threatening cases of acute hepatic failure leading to liver transplant or death have been linked with acetaminophen use. In most cases of hepatic injury, acetaminophen doses exceeded maximum daily limits and often involved the use of more than 1 acetaminophen-containing product .
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.
This medicine 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 this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine 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.
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.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of acetaminophen injection in the elderly.
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 this medicine, 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 this medicine 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.
- Pneumococcal 13-Valent Vaccine, Diphtheria Conjugate
Using this medicine 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.
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 this medicine 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 this medicine, or give you special instructions about the use of food, alcohol, or tobacco.
Using this medicine 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 this medicine, or give you special instructions about the use of food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. 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 this medicine. This medicine 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 this medicine 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 this medicine. 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.
This medicine 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 this medicine.
Serious skin reactions can occur with this medicine. 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 this medicine.
This medicine 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 this medicine.
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).
Side Effects of acetaminophen
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:
- 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
- loss of appetite
- muscle pain or cramps
- muscle spasm, especially of the neck and back
- nausea or vomiting
- numbness or tingling in the hands, feet, or lips
- pain at the injection site
- slow or fast heartbeat
- tightness in the chest
- unusual tiredness or weakness
- Decreased urination
- difficult, fast, or noisy breathing, sometimes with wheezing
- 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
- 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:
- Trouble sleeping
- difficulty having a bowel movement (stool)
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.
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