Acetaminophen: caution should be exercised

As is the case for all medications, acetaminophen must be used wisely, by taking certain precautions. Here is some information on the subject. 

Acetaminophen: well-known, popular… and underestimated

Who hasn’t taken acetaminophen at some point? Better known by its brand name (Tylenol®), acetaminophen is a pain reliever commonly used in Canada, which is also effective for fever. It is available in over 700 over-the-counter and prescription drug formulations, in various strengths and various forms (tablets, liquid gels, capsules, syrup, suppositories, etc.).

It is primarily used for relief of pain due to multiple causes:

  • Headache
  • Sore throat
  • Back pain
  • Earache
  • Toothache
  • Menstrual pain
  • Joint pain (i.e., osteoarthritis)
  • etc.

It is also highly present in products to relieve cold and flu symptoms, where it is combined with other medications (i.e., cough syrup, decongestant, antihistamine, etc.) in a single formulation.

Despite its popularity and being the first choice in treating pain and fever, improper use of acetaminophen can involve health risks that can sometimes be serious.

Taking the proper dose

As with all drugs, you should never exceed the recommended dose of acetaminophen. Dose recommendations depend on age.

For adults and children aged 12 years and older, 4000 mg is the maximum daily recommended dose. For example, this corresponds to:

  • 8 extra-strength tablets (500 mg/tablet)
  • 12 regular-strength tablets (325 mg/tablet)

A single dose of acetaminophen generally ranges between 325 and 1000 mg. It generally can be taken every 4 to 6 hours However, some formulations are more concentrated and last for 8 hours.

In children, the recommended dose depends on weight and age. Although the dosing instructions are indicated on the product label for children, it is best to talk to a pharmacist. The pharmacist can calculate the exact dose to give according to your child's situation and weight, and explain how to accurately measure it (for example, in mLs or tablets). 

Acetaminophen’s safety profile

If the recommended dosage instructions are followed, acetaminophen is one of the safest drugs available.

However, the potential for toxicity increases proportionately with the dose ingested. Therefore, an overdose of acetaminophen may cause liver damage. This may occur after taking a very high single dose or multiple doses that are too high over a certain period of time. Various factors such as alcoholism or liver disease (i.e., hepatitis) may be predisposing factors for liver toxicity.

Every year in Canada, there are thousands of cases of self-induced or accidental acetaminophen intoxication. Many of these cases require hospitalization. Those affected may develop liver damage, which can sometimes lead to acute liver failure. In more severe cases, the person may require a liver transplant or even die. 

In the event of acetaminophen overdose you should immediately contact a poison control centre.

Acetaminophen can also interact with other drugs. For example, taking a high dose of acetaminophen may increase the anticoagulant activity of warfarin (Coumadin®).

Tips for optimal and safe use

Acetaminophen can be taken without any concern unless there is a particular warning or contraindication. To make sure you get the relief you need without being exposed to risks, it is recommended that you:

  • Follow the dose instructions exactly.
  • Never take a dose earlier than indicated.
  • Take note of when you took the last dose as well as the amount.
  • Never take more than one medication containing acetaminophen at the same time.
  • Always read the labels carefully for over-the-counter products. Manufacturers are required to indicate if products contain acetaminophen. Ask the pharmacist for assistance if you are unsure.
  • Whenever possible, avoid taking acetaminophen if you do not have pain or a fever. When taking products with several active ingredients combined in one formulation, this sometimes means taking a drug that we don’t need.

When taking acetaminophen, you should be extra careful due to your health condition, medical history or other drugs you are taking. Talk to your doctor or pharmacist if in doubt.

Consult your pharmacist if you have any questions about the optimal and safe use of over-the-counter drugs.


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Acetaminophen: caution should be exercised

As is the case for all medications, acetaminophen must be used wisely, by taking certain precautions. Here is some information on the subject.