acetaminophen

Acetaminophen is a pain reliever and a fever reducer.

Acetaminophen is used to treat many conditions such as headache, muscle aches, arthritis, backache, toothaches, colds, and fevers.

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

Important information

There are many brands and forms of acetaminophen available and not all brands are listed on this leaflet.

Do not take more of this medication than is recommended. An overdose of acetaminophen can damage your liver or cause death. Call your doctor at once if you have nausea, pain in your upper stomach, itching, loss of appetite, dark urine, clay-colored stools, or jaundice (yellowing of your skin or eyes).

Do not take this medication without a doctor"s advice if you have ever had alcoholic liver disease (cirrhosis) or if you drink more than 3 alcoholic beverages per day. You may not be able to take this medicine. Avoid drinking alcohol. It may increase your risk of liver damage while taking acetaminophen.

Ask a doctor or pharmacist before using any other cold, allergy, pain, or sleep medication. Acetaminophen (sometimes abbreviated as APAP) is contained in many combination medicines. Taking certain products together can cause you to get too much acetaminophen which can lead to a fatal overdose. Check the label to see if a medicine contains acetaminophen or APAP.

In rare cases, acetaminophen may cause a severe skin reaction. Stop taking this medicine and 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 take acetaminophen if you are allergic to it.

Ask a doctor or pharmacist if it is safe for you to take acetaminophen if you have:

• liver disease; or

• a history of alcoholism.

Do not take this medication without a doctor"s advice if you have ever had alcoholic liver disease (cirrhosis) or if you drink more than 3 alcoholic beverages per day. You may not be able to take acetaminophen.

FDA pregnancy category C. Your doctor will determine whether acetaminophen is safe for you to use during pregnancy. Do not use this medicine without the advice of your doctor if you are pregnant.

See also: Pregnancy and breastfeeding warnings (in more detail)

Acetaminophen can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Do not give the medication to a child younger than 2 years old without the advice of a doctor.

How should I take acetaminophen?

Use acetaminophen exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Do not take more of this medication than is recommended. An overdose of acetaminophen can damage your liver or cause death.

Measure liquid medicine with a special dose-measuring spoon or medicine cup, not with a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

If you are treating a child, use a pediatric form of acetaminophen. Use only the special dose-measuring dropper or oral syringe that comes with the specific pediatric form you are using. Carefully follow the dosing directions on the medicine label.

Acetaminophen made for infants is available in two different dose concentrations, and each concentration comes with its own medicine dropper or oral syringe. These dosing devices are not equal between the different concentrations. Using the wrong device may cause you to give your child an overdose of acetaminophen. Never mix and match dosing devices between infant formulations of acetaminophen.

You may need to shake the liquid before each use. Follow the directions on the medicine label.

The chewable tablet must be chewed thoroughly before you swallow it.

Make sure your hands are dry when handling the acetaminophen disintegrating tablet. Place the tablet on your tongue. It will begin to dissolve right away. Do not swallow the tablet whole. Allow it to dissolve in your mouth without chewing.

To use the acetaminophen effervescent granules, dissolve one packet of the granules in at least 4 ounces of water. Stir this mixture and drink all of it right away. To make sure you get the entire dose, add a little more water to the same glass, swirl gently and drink right away.

Stop taking acetaminophen and call your doctor if:

• you still have a fever after 3 days of use;

• you still have pain after 7 days of use (or 5 days if treating a child);

• you have a skin rash, ongoing headache, or any redness or swelling; or

• if your symptoms get worse, or if you have any new symptoms.

This medication can cause unusual results with certain lab tests for glucose (sugar) in the urine. Tell any doctor who treats you that you are using acetaminophen.

Store at room temperature away from heat and moisture.

What happens if I miss a dose?

Since acetaminophen is taken as needed, you may not be on a dosing schedule. If you are taking the medication regularly, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

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

The first signs of an acetaminophen overdose include loss of appetite, nausea, vomiting, stomach pain, sweating, and confusion or weakness. Later symptoms may include pain in your upper stomach, dark urine, and yellowing of your skin or the whites of your eyes.

What should I avoid?

Ask a doctor or pharmacist before using any other cold, allergy, pain, or sleep medication. Acetaminophen (sometimes abbreviated as APAP) is contained in many combination medicines. Taking certain products together can cause you to get too much acetaminophen which can lead to a fatal overdose. Check the label to see if a medicine contains acetaminophen or APAP.

Avoid drinking alcohol. It may increase your risk of liver damage while taking acetaminophen.

Acetaminophen side effects

Get emergency medical help if you have any of these signs of an allergic reaction to acetaminophen: 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. This could occur even if you have taken acetaminophen in the past and had no reaction. Stop taking this medicine and call your doctor right away if you have skin redness or a rash that spreads and causes blistering and peeling. If you have this type of reaction, you should never again take any medicine that contains acetaminophen.

Stop taking this medication and call your doctor at once if you have:

• nausea, upper stomach pain, itching, loss of appetite;

• dark urine, clay-colored stools; or

• jaundice (yellowing of the skin or eyes).

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.

See also: Side effects (in more detail)

Acetaminophen dosing information

Usual Adult Dose for Fever:

IV:
Adults and adolescents weighing 50 kg and over: 1000 mg every 6 hours or 650 mg every 4 hours, with a maximum single dose of 1000 mg, a minimum dosing interval of 4 hours, and a maximum daily dose of acetaminophen of 4000 mg per day.
Adults and adolescents weighing under 50 kg: 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours, with a maximum single dose of 15 mg/kg, a minimum dosing interval of 4 hours, and a maximum daily dose of acetaminophen of 75 mg/kg per day.

Orally or Rectally:
General Dosing Guidelines: 325 to 650 mg every 4 to 6 hours or 1000 mg every 6 to 8 hours

No dose adjustment is required when converting between oral and IV acetaminophen dosing in adults and adolescents. The maximum daily dose of acetaminophen is based on all routes of administration
(i.e. intravenous, oral, and rectal) and all products containing acetaminophen.

Usual Adult Dose for Pain:

IV:
Adults and adolescents weighing 50 kg and over: 1000 mg every 6 hours or 650 mg every 4 hours, with a maximum single dose of 1000 mg, a minimum dosing interval of 4 hours, and a maximum daily dose of acetaminophen of 4000 mg per day.
Adults and adolescents weighing under 50 kg: 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours, with a maximum single dose of 15 mg/kg, a minimum dosing interval of 4 hours, and a maximum daily dose of acetaminophen of 75 mg/kg per day.

Orally or Rectally:
General Dosing Guidelines: 325 to 650 mg every 4 to 6 hours or 1000 mg every 6 to 8 hours

No dose adjustment is required when converting between oral and IV acetaminophen dosing in adults and adolescents. The maximum daily dose of acetaminophen is based on all routes of administration
(i.e. intravenous, oral, and rectal) and all products containing acetaminophen.

Usual Pediatric Dose for Fever:

Preterm neonates 28 to 32 weeks:
IV loading dose: 20 mg/kg followed by 10 mg/kg/dose every 12 hours
Oral: 10 to 12 mg/kg/dose every 6 to 8 hours
Maximum oral daily dose: 40 mg/kg/day
Rectal: 20 mg/kg/dose every 12 hours
Maximum rectal daily dose: 40 mg/kg/day

Preterm neonates 32 to 37 weeks and term neonates less than 10 days:
IV loading dose: 20 mg/kg followed by 10 mg/kg/dose every 6 hours
Oral: 10 to 15 mg/kg/dose every 6 hours
Maximum daily dose: 60 mg/kg/day
Rectal: Loading dose: 30 mg/kg; then 15 mg/kg/dose every 8 hours
Maximum daily dose: 60 mg/kg/day

Term neonates greater than or equal to 10 days:
IV loading dose: 20 mg/kg followed by 10 mg/kg/dose every 6 hours
Oral: 10 to 15 mg/kg/dose every 4 to 6 hours
Maximum daily dose: 90 mg/kg/day
Rectal: Loading dose: 30 mg/kg; then 20 mg/kg/dose every 6 to 8 hours
Maximum daily dose: 90 mg/kg/day

Infants and Children:
IV: Less than 2 years: 7.5 to 15 mg/kg/dose every 6 hours
Maximum daily dose: 60 mg/kg/day
IV: 2 to 12 years: 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours
Maximum single dose 15 mg/kg
Maximum total daily dose: 75 mg/kg/day not to exceed 3750 mg/day
Oral: 10 to 15 mg/kg/dose every 4 to 6 hours as needed; do not exceed 5 doses in 24 hours
Alternatively, the manufacturer lists the following recommended doses:
2.7 to 5.3 kg or 6 to 11 pounds: 0 to 3 months: 40 mg
5.4 to 8.1 kg or 12 to 17 pounds: 4 to 11 months: 80 mg
8.2 to 10.8 kg or 18 to 23 pounds: 1 to 2 years: 120 mg
10.9 to 16.3 kg or 24 to 35 pounds: 2 to 3 years: 160 mg
16.4 to 21.7 kg or 36 to 47 pounds: 4 to 5 years: 240 mg
21.8 to 27.2 kg or 48 to 59 pounds: 6 to 8 years: 320 mg
27.3 to 32.6 kg or 60 to 71 pounds: 9 to 10 years: 400 mg
32.7 to 43.2 kg or 72 to 95 pounds: 11 years: 480 mg
The manufacturer recommends the use of weight to select the dose as the preferred method. If weight is not available, then age may be used.
Rectal: 10 to 20 mg/kg/dose every 4 to 6 hours as needed (Although the perioperative use of high dose rectal acetaminophen (e.g., 25 to 45 mg/kg/dose) has been investigated in several studies, its routine use remains controversial; optimal doses and dosing frequency to ensure efficacy and safety have not yet been established; further studies are needed).

Children greater than or equal to 12 years:
IV: Less than 50 kg: 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours
Maximum single dose: 750 mg/dose
Maximum total daily dose: 75 mg/kg/day (less than or equal to 3750 mg/day)
IV: Greater than or equal to 50 kg: 650 mg every 4 hours or 1000 mg every 6 hours
Maximum single dose: 1000 mg/dose
Maximum total daily dose: 4000 mg/day
Oral or Rectal: 325 to 650 mg every 4 to 6 hours or 1,000 mg 3 to 4 times daily
Maximum daily dose: 4000 mg/day

Usual Pediatric Dose for Pain:

Preterm neonates 28 to 32 weeks:
IV loading dose: 20 mg/kg followed by 10 mg/kg/dose every 12 hours
Oral: 10 to 12 mg/kg/dose every 6 to 8 hours
Maximum oral daily dose: 40 mg/kg/day
Rectal: 20 mg/kg/dose every 12 hours
Maximum rectal daily dose: 40 mg/kg/day

Preterm neonates 32 to 37 weeks and term neonates less than 10 days:
IV loading dose: 20 mg/kg followed by 10 mg/kg/dose every 6 hours
Oral: 10 to 15 mg/kg/dose every 6 hours
Maximum daily dose: 60 mg/kg/day
Rectal: Loading dose: 30 mg/kg; then 15 mg/kg/dose every 8 hours
Maximum daily dose: 60 mg/kg/day

Term neonates greater than or equal to 10 days:
IV loading dose: 20 mg/kg followed by 10 mg/kg/dose every 6 hours
Oral: 10 to 15 mg/kg/dose every 4 to 6 hours
Maximum daily dose: 90 mg/kg/day
Rectal: Loading dose: 30 mg/kg; then 20 mg/kg/dose every 6 to 8 hours
Maximum daily dose: 90 mg/kg/day

Infants and Children:
IV: Less than 2 years: 7.5 to 15 mg/kg/dose every 6 hours
Maximum daily dose: 60 mg/kg/day
IV: 2 to 12 years: 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours
Maximum single dose 15 mg/kg
Maximum total daily dose: 75 mg/kg/day not to exceed 3750 mg/day
Oral: 10 to 15 mg/kg/dose every 4 to 6 hours as needed; do not exceed 5 doses in 24 hours
Alternatively, the manufacturer lists the following recommended doses:
2.7 to 5.3 kg or 6 to 11 pounds: 0 to 3 months: 40 mg
5.4 to 8.1 kg or 12 to 17 pounds: 4 to 11 months: 80 mg
8.2 to 10.8 kg or 18 to 23 pounds: 1 to 2 years: 120 mg
10.9 to 16.3 kg or 24 to 35 pounds: 2 to 3 years: 160 mg
16.4 to 21.7 kg or 36 to 47 pounds: 4 to 5 years: 240 mg
21.8 to 27.2 kg or 48 to 59 pounds: 6 to 8 years: 320 mg
27.3 to 32.6 kg or 60 to 71 pounds: 9 to 10 years: 400 mg
32.7 to 43.2 kg or 72 to 95 pounds: 11 years: 480 mg
The manufacturer recommends the use of weight to select the dose as the preferred method. If weight is not available, then age may be used.
Rectal: 10 to 20 mg/kg/dose every 4 to 6 hours as needed (Although the perioperative use of high dose rectal acetaminophen (e.g., 25 to 45 mg/kg/dose) has been investigated in several studies, its routine use remains controversial; optimal doses and dosing frequency to ensure efficacy and safety have not yet been established; further studies are needed).

Children greater than or equal to 12 years:
IV: Less than 50 kg: 15 mg/kg every 6 hours or 12.5 mg/kg every 4 hours
Maximum single dose: 750 mg/dose
Maximum total daily dose: 75 mg/kg/day (less than or equal to 3750 mg/day)
IV: Greater than or equal to 50 kg: 650 mg every 4 hours or 1000 mg every 6 hours
Maximum single dose: 1000 mg/dose
Maximum total daily dose: 4000 mg/day
Oral or Rectal: 325 to 650 mg every 4 to 6 hours or 1,000 mg 3 to 4 times daily
Maximum daily dose: 4000 mg/day

What other drugs will affect acetaminophen?

Other drugs may interact with acetaminophen, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.