Acetaminophen

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Aug 09, 2022

Warnings

Acetaminophen Risks, Warnings, and Complications

Acetaminophen can cause serious medical problems in certain people. Talk to your doctor or pharmacist about other options to treat moderate pain if you are at high risk of complications from acetaminophen use. Some of the risks of acetaminophen use include:

ACUTE LIVER FAILURE: Taking too much acetaminophen can lead to acetaminophen poisoning with permanent and severe liver damage that can be life-threatening. Signs of liver damage may include dark-colored urine, extreme tiredness, stomach pain, and yellowing of the skin or eyes. Call your healthcare provider right away if you develop these signs and symptoms while taking acetaminophen. The risk of severe liver damage is higher in people who have a history of liver disease, those who drink more than 3 alcoholic beverages per day, and those who take multiple products containing acetaminophen and exceed the maximum daily dose.
ACETAMINOPHEN OVERDOSE: Many non-prescription and prescription medications contain acetaminophen (for example, Excedrin, Tylenol PM, and Dayquil). Make sure you do not exceed the maximum daily dose (3,000 mg to 4,000 mg) combined from all sources that contain acetaminophen. If you are taking multiple products, keep track of your total daily dose to avoid overdosing. If you notice any overdose symptoms, seek emergency medical help.
ALLERGIC REACTIONS: In a small number of people, acetaminophen can cause a serious allergic reaction. Stop taking acetaminophen and get emergency medical help if you develop a peeling or blistering skin rash, hives, or itching after taking acetaminophen.

Precautions Before Starting Acetaminophen

Tell your doctor if you have ever developed a skin rash after taking acetaminophen. Also, tell your doctor if you have an allergy to any of the active or inactive ingredients in acetaminophen tablets or an allergy to any other drugs. Your pharmacy can give you a list of ingredients.

Give your doctor a complete medical history. Acetaminophen may not be right for people with certain medical conditions such as liver disease or alcoholism.

Give your doctor and pharmacist a complete list of your medications, including prescription drugs, over-the-counter medicines, vitamins, supplements, and herbal products. This can help avoid possible drug interactions.

Do not take over-the-counter acetaminophen if you drink three or more alcoholic beverages per day. Talk to your doctor or pharmacist about the safety of drinking alcohol while taking acetaminophen.

Tell your doctor if you are pregnant, could be pregnant, are planning a pregnancy, or are breastfeeding.

People with a condition called phenylketonuria should talk to their doctor about which acetaminophen products are safe for them to use. In this condition, high serum levels of an amino acid called phenylalanine can cause serious problems. Some brands of nonprescription (OTC) acetaminophen products like chewable tablets may contain aspartame which gets broken down into phenylalanine. Regular acetaminophen tablets and liquid medicine don't contain phenylalanine. If you have phenylketonuria, talk to your healthcare provider about what acetaminophen products are safe for you.

Precautions During Use of Acetaminophen

Call your doctor if your pain lasts more than 10 days, your fever gets worse or lasts more than 3 days, or you develop other new symptoms like skin redness after taking acetaminophen.

Do not take a chronic high dose of acetaminophen regularly without talking to a healthcare provider. If you have severe pain, consult a doctor for appropriate pain management options.

Acetaminophen is present along with other medications in many combination products, some of which are available by prescription and some without a prescription. If your doctor has prescribed acetaminophen, do not take other non-prescription pain medications that also contain acetaminophen. Check the label of all over-the-counter medicines, especially those used to treat cough or cold symptoms, as they may contain acetaminophen. Avoid using two or more products at the same time because they may contain the same active ingredient and could lead to an acetaminophen overdose. This is especially true for children younger than 2 years of age.

When giving non-prescription acetaminophen products to children, read the package label to ensure you are using an acetaminophen product that is suitable for children.

Tell your doctor if you become pregnant while taking acetaminophen.

Tell all your doctors you are on acetaminophen before any surgery, including dental procedures.

Acetaminophen Drug Interactions

Certain other drugs can affect how acetaminophen works. Possible interactions between acetaminophen and other medicines can increase the risk of severe adverse effects. Your doctor may change the dose of your medications or monitor you carefully for side effects if there are known interactions between acetaminophen and your other medicines. The following medications can have possible interactions with acetaminophen:

Blood thinners (anticoagulants) like warfarin (Coumadin)
Medications used to relieve pain, fever, coughs, and colds
Certain medications used to treat seizures, such as phenobarbital, phenytoin (Dilantin), and carbamazepine (Tegretol)
Tuberculosis medications like isoniazid (INH)
Phenothiazines (medications used to treat mental illness and nausea)

The above list may not include all the possible interactions of acetaminophen. Give your doctor or pharmacist a complete list of your medications, including prescription drugs, over-the-counter medicines, dietary supplements, and herbal remedies. Also, tell your healthcare professional if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription and over-the-counter medicines.

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