Acetaminophen is a p-aminophenol derivative commonly known as Tylenol or Paracetamol. It is an OTC medicine used to relieve mild to moderate pain and fever. It does not have any anti-inflammatory properties.
Generic names: Acetaminophen
Brand names: Tylenol, Abenol (CAN), Acephen, Altenol, Aminofen, Apra, Atasol (CAN), Cetafen, Calpol, Dolono, Febrol, Genapap, Genebs, Mapap, Panadol
Pharmacologic class: Synthetic non-opioid
Therapeutic class: Analgesic, antipyretic
Mechanism of action: Remains unclear. It is thought that acetaminophen inhibits prostaglandin synthesis in the CNS which results in pain relief and fever reduction.
Indications for use: Mild to moderate pain such as muscle aches, back pain, headache, arthritis, sinus pain, toothaches, and menstrual cramps. Fever reduction.
Precautions and contraindications: Hypersensitivity to acetaminophen. Patients with renal or hepatic impairment. Elderly, pregnant or breastfeeding patients, and children under age 2.
- Activated charcoal and cholestyramine decrease the absorption of acetaminophen
- Barbiturates, carbamazepine, isoniazid, rifampin, alcohol use, and more can increase the risk of hepatotoxicity
- Hormonal contraceptives can decrease the effectiveness of acetaminophen
- Oral anticoagulants may have an increased anticoagulant effect
- Skin rash, pruritus
- Nephrotoxicity, hepatotoxicity
- Anemia, alterations in blood counts
- Nausea, vomiting, constipation, abdominal pain
- Metabolic and electrolyte imbalances such as ↓ sodium bicarbonate, ↓ sodium and calcium, ↑ glucose and bilirubin
- Rare but serious reactions include anaphylaxis and fatal skin reactions such as Stevens-Johnson syndrome
Available preparations: film-coated, chewable, and extended-release tablets, gelcaps, syrups/suspensions/liquids, IV solution, and suppositories.
Dosages: Adults 12 years and older: 325 to 650 mg PO every 4-6 hours as needed or 1,000 mg TID or QID. Dosage should not exceed 4,000 mg in 24 hours.
Children (under 12 years): 10-15 mg/kg
|IV||15-30 minutes||1 hour||4-6 hours|
|PO||0.5-1 hour||10-60 minutes||3-8 hours|
|Rectal||0.5-1 hour||10-60 minutes||3-4 hours|
Nursing Considerations for Acetaminophen
Related nursing diagnoses
- Acute pain
- Chronic pain
- Risk for poisoning related to overdose of acetaminophen
- Risk for impaired liver function
- Deficient knowledge related to misuse
- Assess for an allergy to acetaminophen.
- Assess for pain by having the patient rate on a scale of 1-10, and describe characteristics, duration, and frequency. Assess for chronic conditions that warrant the use of acetaminophen such as arthritis.
- If given as an antipyretic, assess temperature.
- Assess for pregnancy or lactation. Acetaminophen is a category B risk meaning the risk of fetal harm is possible but unlikely. Administration is safe under the prescription and supervision of a healthcare provider.
- Assess for acetaminophen toxicity: nausea, vomiting, abdominal pain, elevated bilirubin and liver enzymes.
- Routinely monitor the effectiveness of acetaminophen by assessing pain levels and fever reduction.
- IV acetaminophen should be infused over 15 minutes.
- For patients who are at risk for hepatotoxicity or renal toxicity, the nurse should closely monitor AST and ALT levels and BUN and creatinine.
- Acetaminophen can cause hematologic reactions. The nurse should monitor for anemia and decreased red and white blood counts.
- The antidote for acetaminophen overdose is N-acetylcysteine given either orally or IV.
Patient Teaching Associated with Acetaminophen
- Instruct patients to never take more than 4,000 mg of acetaminophen per 24 hours. This includes all forms of acetaminophen and acetaminophen-containing products.
- Do not take acetaminophen with alcohol due to the risk of liver toxicity.
- Educate that acetaminophen can increase anticoagulant effects. If the patient is taking warfarin, acetaminophen can increase the risk of bleeding. Teach the patient to monitor for bruising and signs of bleeding, and to prevent the risk of injury.
- Acetaminophen may not be safe for children under the age of 2. Always discuss with a healthcare provider first. Acetaminophen comes in preparations and dosages for children such as Children’s Tylenol liquid. Always use the appropriate dropper or measuring cup provided when administering to children.
- Keep out of reach of children to prevent poisoning.
- Store at room temperature. Suppositories should be stored in the refrigerator.
- Acetaminophen may be taken with or without food.
This is not an all-inclusive list of possible drug interactions, adverse effects, precautions, nursing considerations, or patient instructions. Please consult further with a pharmacist for complete information.
References and Sources
- Gerriets, V., Anderson, J., & Nappe, T. M. (2021, July 3). Acetaminophen – StatPearls. NCBI. Retrieved June 16, 2022, from https://www.ncbi.nlm.nih.gov/books/NBK482369/
- Lewis, A. N. (2012, January 25). IV Acetaminophen (Ofirmev). Pharmacy Times. Retrieved June 16, 2022, from https://www.pharmacytimes.com/view/-iv-acetaminophen-ofirmev-
- Mayo Clinic. (2022, April 1). Acetaminophen (Oral Route, Rectal Route) Proper Use. Mayo Clinic. Retrieved June 16, 2022, from https://www.mayoclinic.org/drugs-supplements/acetaminophen-oral-route-rectal-route/proper-use/drg-20068480
- Schull, P. D. (2013). McGraw-Hill Nurses Drug Handbook, Seventh Edition. McGraw-Hill Education.