Safe Use of Acetaminophen (Tylenol)

Concentration. (Dr. Noorali Bharwani)
Concentration. (Dr. Noorali Bharwani)

Let us start with the use of acetaminophen (Tylenol) in pregnancy. Acetaminophen is generally considered safe in all stages of pregnancy because it doesn’t have the same risks as other over the counter painkillers.

But new animal research says otherwise. Studies following birth outcomes in Denmark and New Zealand have suggested that the use of acetaminophen in pregnancy may be associated with behavioural problems in the new born. Studies carried out in animal models suggest the drug seems to disrupt hormonal function and brain development.

A British study on humans (published in JAMA Pediatrics August 15, 2016) suggests children born to women who used acetaminophen during pregnancy could be at increased risk for several behavioural problems.

The British researchers followed about 14,000 pregnant women who were expected to deliver in 1991 or 1992. They collected detailed information, through clinical visits and questionnaires, about the health and development of the children until the age of seven and looked at the genetic risk factors.

Children born to women who took acetaminophen during the second trimester (18 weeks) and the third trimester (32 weeks) showed emotional problems and behavioural difficulties.

Children born to mothers who took the drug during the third trimester, about six out of 100, had behavioural difficulties – compared with four out of 100 whose mothers did not take the drug.

There was no association with the mother’s use of acetaminophen after giving birth or a partner’s use of acetaminophen. The researchers did not have any information on the dose taken or for how long.

What now?

Some experts believe more research is needed to understand the mechanism of action of acetaminophen during pregnancy. Until we understand this fully, pregnant mothers should follow their physicians’ advice because there is a risk to the fetus of not using acetaminophen when it is required. For example, fever during pregnancy can be dangerous and can lead to pre-term labour.

The bottom line is more research is required. We need to know the dose and duration of acetaminophen use which can be risky. As far as we know, there is no risk when acetaminophen is used during the first trimester.

Under normal circumstances if acetaminophen is taken too often it can cause liver damage. Acetaminophen is a medicinal ingredient in more than 470 products. That is lot of drugs.

There are stricter guidelines and warnings in the U.S. on the safe use of acetaminophen. This move comes as Johnson & Johnson, the makers of Tylenol, face more than 85 personal injury lawsuits in U.S. federal court that blame Tylenol for liver injuries and deaths. The U.S. Food and Drug Administration is planning to curtail the use of some acetaminophen products. The maximum daily dose is 4 grams, in people with healthy liver and kidneys.

Acetaminophen was discovered in 1877. It is used to treat mild to moderate pain and fever. There is poor evidence for fever relief in children. It is typically taken by mouth or rectally, but is also available intravenously. Effects last between two and four hours.

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