Acetaminophen | Nursing Considerations

Acetaminophen, often referred to by the brand name Tylenol, is one of the most common medications you'll use in your life and throughout your nursing career. Roughly 20%⁽¹⁾ of American adults take acetaminophen in a given week.

Its combination of analgesic⁽²⁾ and antipyretic⁽³⁾ properties make it one of the most common over-the-counter medications to help with mild to moderate pain and conditions that include fevers.

Here's a breakdown of everything you need to know about acetaminophen as a nurse, or future nurse, from its names, dosage information, and more.

Acetaminophen (Tylenol) Key Information

Acetaminophen is also known as Paracetamol. It's a p-aminophenol derivative and an over-the-counter (OTC) medication that people commonly use to help with mild to moderate pain and fever⁽⁴⁾. Acetaminophen research has not shown any anti-inflammatory elements⁽⁵⁾and therefore it is not considered an NSAID.

Acetaminophen is the generic name of the drug, but there are several brand names that you'll come across (not exhaustive):

• Abenol (CAN)
• Acephen
• Altenol
• Genapap
• Aminofen
• Apra
• Genebs
• Atasol (CAN)
• Calpol
• Tylenol
• Mapap
• Cetafen
• Dolono
• Fenrbol
• Cetafen
• Panadol

Acetaminophen is part of the pharmacologic class synthetic non-opioid.

Mechanism of Action

Researchers currently believe that the analgesic mechanism of action (MOA) of acetaminophen, is through the activation of TRPV1 and/or CB1 receptors⁽⁶⁾. However, the evidence is not conclusive and further studies are needed.

Indications for Use

Acetaminophen is clinically used to treat mild to moderate pain in patients as well as to reduce fever. Some indications for use include:

• Back pain
• Muscle aches
• Headaches
• Colds and fever
• Arthritis

Contraindications for Acetaminophen

There are several precautions and contradictions to consider before administering acetaminophen:

• Hypersensitivity to acetaminophen
• Patients with renal or hepatic impairments
• Elderly patients
• Pregnant and breastfeeding patients
• Children under two years old

Hypersensitivity to acetaminophen could lead to anaphylaxis, fixed drug eruption, urticaria/angioedema, rhinoconjunctivitis, or Stevens-Johnson Syndrome.

Since high doses of acetaminophen can cause severe and fatal liver damage⁽⁷⁾, it can be dangerous to give to patients who have a history of substance or alcohol abuse or liver issues.

Some studies suggest there is evidence that administering acetaminophen to pregnant women can increase the risks of the child developing neurodevelopment disorders⁽⁸⁾.

Drug Interactions and Side Effects

Some of the most common drug interactions to consider when administering acetaminophen for patients include (not exhaustive):

• Those on oral anticoagulants might experience an increase in the anticoagulant effect when taking acetaminophen⁽⁹⁾
• Hormonal contraceptives can make acetaminophen less effective⁽¹⁰⁾
• Taking cholestyramine or activated charcoal can decrease how well the body absorbs acetaminophen (as well as other drugs)
• Carbamazepine, Rifampin, Barbiturates, Isoniazid, and alcohol can increase the patient's risk of hepatotoxicity

While acetaminophen is not typically thought of as a high-risk drug, there are a significant number of adverse event reports collected annually by medical reporting agencies⁽¹¹⁾. Potential side effects include (not exhaustive):

• Hepatotoxicity
• Nephrotoxicity
• Skin rash
• Nausea
• Vomiting
• Abdominal pain
• Constipation
• Change in blood counts
• Anemia⁽¹²⁾
• Sodium bicarbonate imbalances
• Sodium and calcium imbalances
• Glucose and bilirubin imbalances
• Stevens-Johnson syndrome
• Anaphylaxis⁽¹³⁾

Administration and Dosage

When administering acetaminophen there are several options for administration. These are your options for administration:

• Film-coated
• Extended-release tablets
• Chewable tablets
• Gelcaps
• IV solution
• Suppositories
• Syrups or liquid

The dosage recommendations will vary slightly based on the preparation. Importantly, dosage should not exceed 4,000 mg in a 24-hour period. Typical dosage could look something like one of the following:

• 325 mg to 650 mg orally every four to six hours or PRN (as needed)
• 1,000 mg TID (3 times) or QID (4 times) per day

As pointed out by one of our longstanding nursing professionals with over 40 years of experience, in a 2004 double-blind study no significant differences in discomfort scores were found between PRN versus regularly scheduled administration⁽¹⁴⁾.

Dosage for Children

For the most precise dosage recommendations, weight should be considered as opposed to just age as studies have shown that weight-based dosing may be more effective⁽¹⁵⁾. To calculate proper acetaminophen dosages for children, use the following guidelines based on age groups.

For neonates, or children under 28 days of age:

• 10-15 mg/kg PO (oral) q6-8h PRN
• Never exceeding a maximum of 60 mg/kg/day

For infants and children under the age of 12:

• 10-15 mg/kg PO q4-6h PRN
• Not to exceed 75 mg/kg/day or 1 g/4h or 4 g/day from all sources

As other experienced nurses in the community have pointed out, the danger with Tylenol and children is child cold prep may contain acetaminophen so be sure to include that in any calculations.

Acetaminophen (Tylenol) Nursing Considerations / Implications

Even though acetaminophen might be one of the most commonly used medications both clinically and OTC, acetaminophen toxicity is responsible for 2,600 hospitalizations, and 500 deaths per year in the United States⁽¹⁵⁾.

Nursing Assessment

If you're administering acetaminophen to a patient, you'll want to assess for an allergy to the medication. Signs of an allergic reaction can include:

• hives and/or skin rashes
• swelling of the face, or injection site if given via an IV

Since acetaminophen is given for mild to moderate pain, you'll need to assess the patient's pain level. Have them rate their pain on a scale of one to ten and then describe the pain. As a nurse, you'll want to know if the pain is constant, blunt, or sharp, how long the pain lasts if it's not constant, or if something makes it worse or better.

When using acetaminophen as an antipyretic (to help reduce fever), you'll want to assess the patient's temperature often to ensure the medication is bringing the fever down.

If your patient is unaware if they're pregnant or not, you'll want to run a pregnancy test. Women who are pregnant or breastfeeding need to be careful with acetaminophen use. While you can still administer the medication to them, it's a category B risk.

Category B risks mean that there can be fetal harm, but it's rare. Since it's rare but can happen, you'll need to monitor the patient for signs of distress in the fetus or baby.

Lastly, you'll need to assess for acetaminophen toxicity. Acetaminophen toxicity signs include vomiting, nausea, abdominal pain, and elevated liver and bilirubin enzymes.

Nursing Interventions

After administering Acetaminophen, you'll need to monitor the patient routinely. You're looking for the drug's effectiveness, which you can do by monitoring their temperature if you're using it for fever reduction and assessing their pain on a scale of one to ten.

When you give the drug through an IV, you'll need to infuse the medication over the course of 15 minutes to prevent overloading the body too quickly.

If you have a patient at a higher risk for renal toxicity or hepatotoxicity, you'll need to closely monitor their ALT and AST levels, creatinine, and BUN levels. Be sure you're checking your patient's red and white blood counts because Acetaminophen can cause anemia and lower these counts.

While Acetaminophen overdose is relatively rare, it can happen when you're not careful. If you notice your patient is overdosing on the drug, the antidote is N-Acetylcysteine, which you can give via an IV or orally.

Patient Education

It's important that you take the time to educate your patient—or their parents or guardians, if they're a child. Proper patient education can prevent further complications and acetaminophen overdose. The key points patients need to understand are:

• Keep the bottle out of reach of children to prevent poisoning.
• Store oral gel capsules and tablets at room temperature.
• Store suppositories in the refrigerator.
• You can take the medication with or without food, but food might prevent nausea in sensitive patients.
• Ensure they know they cannot take more than 4,000 mg in 24 hours (including the medication you prescribe and other medications that include Acetaminophen).
• Don't take the medication with any alcohol because it can increase the risk of liver toxicity.
• Acetaminophen can have anticoagulant effects, so if they're on any blood thinners, they are at a higher risk of bleeding. You'll want to teach them how to monitor for signs of bleeding and bruises and try to prevent injuries.
• When giving children Acetaminophen, always consult with a physician and use the provided measuring cup or dropper for proper dosing.

Acetaminophen FAQs

Below you'll find some frequently asked nursing questions about acetaminophen.

Can acetaminophen ruin your liver?

The short answer is yes, it can. When you take the medication in elevated doses or with alcohol regularly, it can have negative and potentially life-threatening effects on the liver. When sticking to the recommended dosage and avoiding alcohol, liver problems are rare.

Can you drink caffeine when taking acetaminophen?

While there's nothing stopping someone from drinking coffee or a caffeinated beverage while taking this medication, there is evidence that it can increase your chance of liver damage. If the Acetaminophen product you're taking already has caffeine in it, then it can have adverse side effects if you're sensitive to caffeine.

How long does it take for Acetaminophen to work?

Most people will start to feel the pain-relieving effects of Acetaminophen within 45 minutes of taking it if they've taken it orally. Some feel the effects sooner, and if it's being given via an IV, the results are far quicker.

Are Acetaminophen and Ibuprofen the same thing?

No, they're not. While they're both similar in the way that they can help reduce pain and fever, Acetaminophen primarily works in the brain to reduce pain and fever, and Ibuprofen does this but also helps reduce inflammation and swelling throughout the body.

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