Acetaminophen

Name: Acetaminophen

Acetaminophen Dosage

Dosages of acetaminophen range from 300 to 1,000 milligrams (mg). The maximum dose of acetaminophen in a 24-hour period should not exceed 4,000 mg.

  • For adults and children 12 and older: Recommended daily dose is 650 to 1,000 mg every four to six hours, not to exceed 4,000 mg in 24 hours.
  • For extended-release acetaminophen: Recommended dose is 1,300 mg every eight hours, not to exceed 3,900 mg in 24 hours.
  • For children younger than 12: Recommended dose is 10 to 15 mg every four to six hours, not to exceed five doses of 50 mg to 75 mg in 24 hours.
  • Extra Strength Tylenol products should not be given to children younger than 12.

Extended-release acetaminophen tablets need to be swallowed whole — do not chew, divide, crush, or dissolve them.

If taking a disintegrating tablet (Tylenol's Meltaways, for example), allow it to dissolve, or chew it before swallowing.

If giving acetaminophen to a child, make sure it is the right medication for your child's age, and be sure to use the dosage cup or syringe that comes with the product.

Stop taking acetaminophen and seek medical help if your fever doesn't break after three days or your pain persists after seven days (five days for children).

You should also contact your doctor if you have a skin rash, a continuing headache, any redness or swelling, or if your symptoms worsen, or new ones appear.

Missed Dose of Acetaminophen

Take the missed dose as soon as you remember.

If it's close to the time for your following dose, forget about the missed dose and take your next dose.

Do not double-up on doses to make up for a missed one.

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Reviewed on 7/20/2017 References Reference: FDA Prescribing Information

Pronunciation

(a seet a MIN oh fen)

Pharmacologic Category

  • Analgesic, Nonopioid

Use Labeled Indications

Pain:

Injection: Management of mild to moderate pain in patients ≥2 years of age; management of moderate to severe pain when combined with opioid analgesia in patients ≥2 years

Oral, Rectal: Temporary relief of minor aches, pains, and headache

Fever: Temporary reduction of fever

Drug Interactions

Alcohol (Ethyl): May enhance the hepatotoxic effect of Acetaminophen. Monitor therapy

Barbiturates: May increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Exceptions: Amobarbital; Butabarbital; Butalbital; Methohexital; PENTobarbital; Secobarbital; Thiopental. Monitor therapy

Busulfan: Acetaminophen may increase the serum concentration of Busulfan. Monitor therapy

CarBAMazepine: May increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Monitor therapy

Cholestyramine Resin: May decrease the absorption of Acetaminophen. Effect is minimal if cholestyramine is administered 1 hour after acetaminophen. Consider therapy modification

Dapsone (Topical): May enhance the adverse/toxic effect of Methemoglobinemia Associated Agents. Monitor therapy

Dasatinib: Acetaminophen may enhance the hepatotoxic effect of Dasatinib. Dasatinib may increase the serum concentration of Acetaminophen. Consider therapy modification

Fosphenytoin-Phenytoin: May decrease the serum concentration of Acetaminophen. Specifically, serum concentrations of acetaminophen may be decreased (leading to decreased efficacy), but the formation of the toxic N-acetyl-p-benzoquinone imine (NAPQI) metabolite may be increased (leading to increased hepatotoxicity). Monitor therapy

Imatinib: Acetaminophen may enhance the hepatotoxic effect of Imatinib. Monitor therapy

Isoniazid: May enhance the adverse/toxic effect of Acetaminophen. Monitor therapy

LamoTRIgine: Acetaminophen may decrease the serum concentration of LamoTRIgine. Monitor therapy

MetyraPONE: May increase the serum concentration of Acetaminophen. More importantly, by inhibiting the conjugative metabolism of acetaminophen, metyrapone may shift the metabolism towards the oxidative route that produces a hepatotoxic metabolite. Monitor therapy

Mipomersen: Acetaminophen may enhance the hepatotoxic effect of Mipomersen. Monitor therapy

Nitric Oxide: May enhance the adverse/toxic effect of Methemoglobinemia Associated Agents. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Management: Monitor patients for signs of methemoglobinemia (e.g., hypoxia, cyanosis) when nitric oxide is used in combination with other agents associated with development of methemoglobinemia. Avoid lidocaine/prilocaine. Monitor therapy

Phenylephrine (Systemic): Acetaminophen may increase the serum concentration of Phenylephrine (Systemic). Monitor therapy

Prilocaine: Methemoglobinemia Associated Agents may enhance the adverse/toxic effect of Prilocaine. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Management: Monitor patients for signs of methemoglobinemia (e.g., hypoxia, cyanosis) when prilocaine is used in combination with other agents associated with development of methemoglobinemia. Avoid lidocaine/prilocaine in infants receiving such agents. Monitor therapy

Probenecid: May increase the serum concentration of Acetaminophen. Probenecid may also limit the formation of at least one major non-toxic metabolite, possibly increasing the potential for formation of the toxic NAPQI metabolite. Consider therapy modification

Sodium Nitrite: Methemoglobinemia Associated Agents may enhance the adverse/toxic effect of Sodium Nitrite. Combinations of these agents may increase the likelihood of significant methemoglobinemia. Monitor therapy

SORAfenib: Acetaminophen may enhance the hepatotoxic effect of SORAfenib. SORAfenib may increase the serum concentration of Acetaminophen. Consider therapy modification

Tetracaine (Topical): May enhance the adverse/toxic effect of Methemoglobinemia Associated Agents. Monitor therapy

Vitamin K Antagonists (eg, warfarin): Acetaminophen may enhance the anticoagulant effect of Vitamin K Antagonists. This appears most likely with daily acetaminophen doses exceeding 1.3 or 2 g/day for multiple consecutive days. Monitor therapy

About acetaminophen

Type of medicinePainkiller
Used forPain and high temperature (fever) in adults and children
Also calledAcephen®; Anacin®; Infants' FeverAll®; Mapap®; Panadol®; Tylenol®
Available asTablet, capsule, soluble tablet, 'melt in the mouth' tablet, chewable tablet, oral liquid and suppository

Acetaminophen (also known as paracetamol) belongs to a group of medicines known as analgesics, or painkillers. It is used to relieve mild-to-moderate pain such as headaches, muscle aches, menstrual pain and toothache. It is also useful for lowering a raised temperature (fever) during a cold or flu or after childhood immunisations.

Acetaminophen is a common painkiller and is available to buy from many retail outlets as tablets/capsules and as liquid medicine. Many brands of 'over-the-counter' combination painkillers contain acetaminophen, as do many cold and flu remedies. It is important that you check the label on any preparation that you buy to make sure that you are not taking more than one preparation containing acetaminophen.

Before taking acetaminophen

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking acetaminophen it is important that your physician knows:

  • If you are pregnant, trying for a baby, or breast-feeding. This is because, while you are expecting or feeding a baby, you should only take medicines on the recommendation of a physician.
  • If you have a serious problem with the way your liver works, or if you regularly drink three or more alcoholic drinks per day.
  • You are taking medicines prescribed by a physician.
  • If you have ever had an allergic reaction to a medicine.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

Getting the most from your treatment

  • If your pain is not relieved by taking acetaminophen, speak with your pharmacist or physician for further advice.
  • It is important that you do not take more than one preparation containing acetaminophen at a time. Acetaminophen is an ingredient in a number of over-the-counter preparations, including many cold and flu products. Acetaminophen may also be contained in painkillers which you may already have been prescribed by your physician. Before taking any other medicines, check the label to see whether they contain acetaminophen.
  • If you buy any medicines, check with your physician or a pharmacist that they are suitable for you to take with acetaminophen.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking acetaminophen.

Side effects

No information provided.

Acetaminophen Overview

Acetaminophen is both an over-the-counter and a prescription medication. Both forms of the medication are used to treat mild to moderate pain and to reduce fever. This medication page refers to the prescription form of acetaminophen.

Acetaminophen belongs to a group of drugs called analgesics and antipyretics. These work by changing the way the body feels pain and by cooling the body.

The prescription form of this medication is available in an injectable form to be given directly into a vein (IV) by a healthcare professional.

Common side effects of acetaminophen include nausea, vomiting, headache, and insomnia.

Acetaminophen and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Acetaminophen falls into category C. There are no well-controlled studies that have been done in pregnant women. Acetaminophen should be used during pregnancy only if the possible benefit outweighs the possible risk to the unborn baby.

Acetaminophen Usage

Take acetaminophen exactly as prescribed.

This medication is available in an injectable form to be given directly into a vein (IV) by a healthcare professional.

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take your next dose at the regular time. Do not take two doses of acetaminophen at the same time.

Acetaminophen Overdose

If you take too much acetaminophen, call your healthcare provider or local Poison Control Center or seek emergency medical attention right away.

If acetaminophen is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

What should i discuss with my healthcare provider before taking acetaminophen?

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.

Acetaminophen can pass into breast milk and may harm a nursing baby. Do not use this medication without telling 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.

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.

Acetaminophen side effects

Get emergency medical help if you have 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 this medicine 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 acetaminophen 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.

For Healthcare Professionals

Applies to acetaminophen: compounding powder, intravenous solution, oral capsule, oral granule effervescent, oral liquid, oral powder for reconstitution, oral suspension, oral tablet, oral tablet chewable, oral tablet disintegrating, oral tablet extended release, rectal suppository

General

In general, acetaminophen is well-tolerated when administered in therapeutic doses. The most commonly reported adverse reactions have included nausea, vomiting, constipation. Injection site pain and injection site reaction have been reported with the IV product.[Ref]

Hepatic

Common (1% to 10%): Increased aspartate aminotransferase
Rare (less than 0.1%): Increased hepatic transaminases
Frequency not reported: Liver failure[Ref]

Gastrointestinal

Very common (10% or more): Nausea (up to 34%), Vomiting (up to 15%)
Common (1% to 10%): Abdominal pain, diarrhea, constipation, dyspepsia, enlarged abdomen
Frequency not reported: Dry mouth[Ref]

Hypersensitivity

Postmarketing reports: Anaphylaxis, hypersensitivity reactions[Ref]

Hematologic

Common (1% to 10%): Anemia, postoperative hemorrhage
Very rare (less than 0.01%): Thrombocytopenia, leucopenia, neutropenia[Ref]

Dermatologic

Common (1% to 10%): Rash, pruritus
Rare (less than 0.1%): Serious skin reactions such as acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, and toxic epidermal necrolysis
Very rare (less than 0.01%): Pemphigoid reaction, pustular rash, Lyell syndrome
:[Ref]

Respiratory

Common (1% to 10%): Dyspnea, abnormal breath sounds, pulmonary edema, hypoxia, pleural effusion, stridor, wheezing, coughing[Ref]

Cardiovascular

Common (1% to 10%): Peripheral edema, hypertension, hypotension, tachycardia, chest pain[Ref]

Metabolic

Common (1% to 10%): Hypokalemia, hyperglycemia[Ref]

Nervous system

Common (1% to 10%): Headache, dizziness
Frequency not reported: Dystonia

Musculoskeletal

Common (1% to 10%): Muscle spasms, trismus

Psychiatric

Common (1% to 10%): Insomnia, anxiety

Genitourinary

Common (1% to 10%): Oliguria

Local

Common (1% to 10%): Infusion site pain, injection site reactions

Ocular

Common (1% to 10%): Periorbital edema

Other

Common (1% to 10%): Pyrexia, fatigue
Rare (0.01% to 0.1%): Malaise

Some side effects of acetaminophen may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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