Acetaminophen

(uh-see-toe-MIN-uh-fin)

Trade/other name(s): Acephen, Anacin Aspirin Free, Aspirin-Free Excedrin, Feverall, Gelpirin, Genapap, Genebs, Liquiprin, Supac, Tylenol, Vanquish, Wygesic, and more

Why would this drug be used?

Acetaminophen is used to help relieve pain. It is used alone for mild pain, and along with other medicines for severe pain. It is also an antipyretic, which means it can lower body temperature if you have a fever. You can buy acetaminophen over the counter, without a prescription.

Acetaminophen is sold alone and in combination formulas with other over the counter medicines, including many headache, sinus, cold, and flu remedies. It is also added to or taken with some prescription pain medicines to make them work better for severe pain.

How does this drug work?

Acetaminophen belongs to a group of drugs called non-opioid pain medicines, meaning that it is not in the same family as morphine or codeine. It reduces the level of prostaglandins in the body, although exactly how it does this is not clearly understood. (Prostaglandins are substances made by most of the cells in the body. They have a role in many body functions, including pain and inflammation.) The lower prostaglandin levels help prevent pain receptors from passing the pain message to the brain. This drug also reduces fever by helping the body to expand blood vessels near the skin so that heat is lost from the body.

Before taking this medicine

Tell your doctor…

• If you are allergic to anything, including medicines, dyes, additives, or foods.
• If you have any medical conditions such as liver disease (including hepatitis) or kidney disease. These conditions may require that your medicine dose or timing be changed.
• If you drink more than 3 alcoholic drinks per day. This can increase your risk of serious liver damage while taking acetaminophen.
• If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. Although there have been no reports of harm in animals or humans, this drug has not been tested on pregnant women.
• If you are breast-feeding. Small amounts of acetaminophen pass into breast milk, and may affect the baby. There have been no reports of harm to date.
• About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Alcohol can increase the chance of serious liver damage if you are also taking acetaminophen. Other drugs that can damage the liver may also increase this risk, especially if your liver is already impaired.

The pain medicine diflunisal (Dolobid) can raise the level of acetaminophen in the body. If you take diflunisal, talk with your doctor before you take acetaminophen.

Warfarin (Coumadin), a blood thinner, may have a stronger effect in some people taking acetaminophen. Your doctor may want to watch your lab tests more closely while you are taking acetaminophen and re-check you after you stop taking it.

If you take medicines for seizures, you may be more likely to have liver problems if you also take large doses of acetaminophen.

Check with your doctor, nurse, or pharmacist about whether other medicines, vitamins, herbs, and supplements, can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Acetaminophen is given by mouth as a pill, capsule, liquid, powder, or drops. It also comes as a suppository to be given rectally. The dose depends upon why the drug is being taken and by how well your liver is working. Take the pill, capsule, powder, or drops with a glass of water or juice. If you are taking an extended-release caplet or tablet, do not chew, break, dissolve, or crush the pill.

Remove the wrapper and moisten the suppository with cold water if needed. Lie down on your side, and insert the suppository into the rectum about an inch. Stay in that position for a few minutes, then get up and wash your hands well.

Take this drug exactly as your doctor tells you, or follow the directions on the label. If you do not understand the instructions, your doctor or nurse can explain them. Store the medicine in a tightly closed container away from heat and moisture and away from children and pets.

Precautions

Acetaminophen can damage the liver in certain people. Your doctor may suggest lowering the dose or taking the medicine less often if you have liver or kidney damage.

Acetaminophen is often added to other medicines, both prescription and over-the-counter. To avoid overdosing, ask your doctor, pharmacist, or nurse if acetaminophen is in any of your medicines before you start taking it. Read the ingredient list on all non-prescription remedies for headache, sinus, cold, flu, sleep, and other problems. If you are not sure, ask your pharmacist.

It is important not to drink alcohol if you are taking acetaminophen because this can increase the chance of liver damage. Your doctor, nurse, or pharmacist can tell you more about this.

Because fever can be a sign of an infection, and taking acetaminophen regularly could cover up this important sign of infection, ask your doctor if you should take acetaminophen when you have a fever. Your doctor might want to find out what is causing the fever before you start taking acetaminophen.

Acetaminophen may interfere with certain lab tests. If you are having blood drawn for lab work, call the lab 3 or 4 days ahead to find out if you will need to stop taking acetaminophen before the blood is drawn. In people with diabetes, it may cause blood sugar tests to give the wrong reading. Talk with your doctor or diabetes nurse about how to best handle this.

If you think that you or someone else may have taken an overdose of acetaminophen, get emergency help right away. There are often no signs of poisoning for more than 2 days after the overdose, but treatment must be started as soon as possible to prevent severe liver damage or death. Sometimes treatment that is started more than 24 hours after the overdose is taken does not work.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.

Rare

• liver damage, with yellow eyes or skin, abnormal bleeding (most often with larger doses, in those who drink, or people who had some liver damage before)*
• upset stomach
• allergic reaction, with symptoms such as itching, skin welts (hives), swelling of face or throat, or trouble breathing or swallowing

*See "Precautions" section for more detailed information.

There are other side effects not listed above thatcan also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984 (FDA cannot verify dates of drugs approved before 1984).

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.