Acetaminophen Damages the Fetus

Many women take acetaminophen when pregnant, but acetaminophen damages the fetus. It is important to realize that acetaminophen is a common over-the-counter pain reliever. In addition, it is also often combined with codeine as headache pills. Acetaminophen goes under these brand names: Tylenol, Tylenol Arthritis Pain, Tylenol Ext and Little Fevers Children’s Fever/Pain Reliever. The international name of acetaminophen is the name “paracetamol”.

An international group of 13 scientists are calling health care professionals to limit the use of acetaminophen in pregnant women. CNN reported about this under this link.

These scientists published an article in the medical journal Nature on the dangers of paracetamol use in pregnancy.  Specifically, they said that acetaminophen can alter fetal development, which includes reproductive, neurodevelopmental and urogenital disorders.

History of acetaminophen

The chemical name for acetaminophen is N-acetyl-p-aminophenol. Acetaminophen is simply a shortened version of that chemical name. It was introduced in the US in 1955 as Tylenol® and in the United Kingdom in 1956 under the brand name Panadol®. In particular, acetaminophen was recommended to control fevers and to help with pain control.

In the 1960’s the Swiss watch industry provided workers who complained of headaches freely with acetaminophen. With this in mind, within a few years studies showed that many of these women who took a lot of this medication developed kidney problems. This led to an increase of the creatinine level in the blood. The kidney damage from acetaminophen was dubbed “phenacetin kidneys”. Outside of the US acetaminophen has the name phenacetin. Many of these patients subsequently had to receive dialysis and later kidney transplants.

Acetaminophen toxicity

The recommended dose of acetaminophen is 650 mg to 1000 mg 4-6 times daily, not to exceed 4 grams/day. The therapeutic window for this drug is very narrow, because 7.5 grams per day to 10 grams per day are already toxic. For children the dose is 15 mg/kg every 6 hours to a maximum of 60 mg/kg per day.

The other known toxicity concerns liver function. This article about Tylenol toxicity explains this in more detail.

Many people do not know about the limit for the over-the-counter acetaminophen and take too much for a fever or a painful condition. Just because a drug is available over the counter does not mean that it is harmless. If you don’t watch for toxic levels, you could end up dead or find yourself waiting for a liver transplant.

New evidence that acetaminophen damages the fetus

91 scientists from Australia, Brazil, Canada, Europe, Israel, Scotland, the UK and US have signed a declaration. In it they ask pregnant women not to take acetaminophen “unless its use is medically indicated”. Among the reasons for the declaration is that acetaminophen certainly can cause neural tube defects and cardiovascular disorders in fetuses. Pediatrician Dr. Leonardo Trasande, director of environmental pediatrics at NYU Langone Health, did not partake in this research. He has done safety studies on acetaminophen and pointed out the similarity in chemical structure between acetaminophen and phthalates. Like phthalates acetaminophen disrupts the reproductive development in animals and humans.

Evidence for neurodevelopmental disruption

Dr. Shanna Swan, a professor of environmental medicine at the Icahn School of Medicine at Mount Sinai in New York said: “There’s enough evidence to find increased risk of undescended testicles and a shortening of the anogenital distance, which is a predictive of later decreased sperm count and decreased fertility. We also see impaired ovarian function which has consequences for later fertility, although females have been less studied.”

The conditions that relate to acetaminophen toxicity were attention deficit hyperactivity disorder (ADHD), behavior abnormalities and autism spectrum disorders. In addition, language delays, conduct disorders and decreased IQ were due to neurodevelopment disruption from acetaminophen toxicity.

Mechanism of action of acetaminophen and side effects

Acetaminophen has been on the market for over 60 years. But scientists still don’t know exactly how it acts in the body to help control pain and reduce fever. There is a consensus that acetaminophen acts on the central nervous system inhibiting the synthesis of prostaglandins. These biological compounds have a leading role in causing fever, pain and inflammation. But the scientific proof for this consensus is still outstanding.

Side effects

There are a multitude of side effects that can occur with the use of acetaminophen. Common side effects are hives, itching, swelling of the mouth and throat and tingling in the mouth or throat. Other side effects are swelling in the face or hands, breathing difficulties or chest tightness. Acetaminophen can cause a loss of appetite, nausea and vomiting. Severe stomach pain can be another symptom of acetaminophen side effects. As you can see from the above link there are many more known side effects of acetaminophen.

Acetaminophen Damages the Fetus

Acetaminophen Damages the Fetus


Acetaminophen (=paracetamol, phenacetin) is a popular over-the-counter fever and pain remedy. But a narrow therapeutic width can cause serious overdoses where both the liver and the kidneys suffer irreparable damage. When people unknowingly take too much acetaminophen, they enter into the toxic range. This can cause disability and death. Kidney damage from acetaminophen became known as “phenacetin kidneys” already in the 1960’s in female workers of the watch industry in Switzerland. They developed headaches from constantly working with magnifying glasses and had free access to acetaminophen provided by the employer. Later, in North America liver disease developed when patients overdosed with over-the-counter acetaminophen for fever and pain control.

Interruption of fetal development from exposure of the fetus to acetaminophen 

At the present time the focus is on newer findings of researchers. They noticed that exposure of pregnant women to acetaminophen damages the fetus. This results in undescended testicles and a shortening of the anogenital distance which is a predictive of later decreased sperm count and decreased fertility. These are findings for males. Findings in females are less studied at this point in time. Dr. Leonardo Trasande pointed out the similarity in chemical structure between acetaminophen and phthalates. Like phthalates acetaminophen disrupts the reproductive development in animals and humans. Patients should take acetaminophen only under supervision with doses that are safe. The old notion that acetaminophen would be safe in pregnancy is no longer true in light of the new medical findings. Any pregnant woman should discuss with her physician what she can safely take.


Go Easy On Tempra And Tylenol In Young Kids

With cold and flu season around the corner, the medicine shelf will fill up with remedies that provide symptomatic relief for those who caught a bug. Children who have an elevated temperature will very likely receive over the counter medication such as Tempra drops or Tylenol for children. These preparations have been around for decades, and parents are usually confident that they are harmless.
A Lancet article points out that there are certain risks associated with them, and the most sensitive age group are the youngest children. A study documented that the mother’s use of paracetamol (identical to acetaminophen or Tylenol) during pregnancy can be associated with the development of asthma in 6 to 7 year old children. More recently 205,487 children in the age group of 6 to 7 were included in a survey. The children were from 73 centers in 31 countries. In the analysis of data the use of paracetamol in the first year of life was checked against the risk of asthma symptoms once the children were 6 to seven years old. Paracetamol use in the first year of life also played a role in the increased risk of rhinoconjunctivitis and eczema.

Go Easy On Tempra And Tylenol In Young Kids

Go Easy On Tempra And Tylenol In Young Kids

With these results, parents should resort to the children’s’ Tylenol and Tempra drops only, if fairly aggressive intervention is necessary. Too often over the counter meds are used “just in case he or she is coming down with something”. Symptomatic home remedies in children such as lukewarm baths to bring down an elevated temperature, cool fluids bring relief, and ice packs still have their place in the control of mild febrile symptoms.

The Lancet 2008; 372:1039-1048

Last edited December 3, 2012

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Acetaminophen Overdosing Hazards

The FDA has expressed some concerns about the self-medicating with acetaminophen as this can led to an acetaminophen overdose. The over-the-counter medication is commonly used and especially in the winter season many sufferers of colds or influenzas will keep it handy. It is readily available, not only in pharmacies but also in supermarkets under the generic name or under brand names such as the commonly used Tylenol. It exists in dosages for adults and there are pediatric preparations like Children’s Tylenol. Acetaminophen is also a common ingredient in cold remedies. Every vial displays a clear warning that the content is enough to cause serious harm. Dosage instructions are also clearly spelled out.
More than 200 million people take Tylenol each year and 400 people die of liver failure every year, as they have accidentally taken too much.
Dr. Charles Cain from the New York Presbyterian Hospital has cautioned that overdoses can happen relatively easy. A patient is not to exceed 4 grams of acetaminophen per day. If the pain reliever is taken every 4 hours instead of the recommended interval of 6 hours, such as 2 extra-strength Tylenol at 500 mg each and some cold medication is added to that, patients may easily reach 4-6 grams of acetaminophen per day. If this practice continues for a few days, it can lead to liver damage, because the liver cannot keep up with the elimination of the drug. Other substances metabolized by the liver such as alcohol can become a serious hazard, if they are combined with acetaminophen. The effects of alcohol slow down the elimination of Tylenol by the liver.

Acetaminophen Overdosing Hazards

Acetaminophen Overdosing Hazards

It is for this reason that it is important to observe closely how much of the medication is taken in total: if a patient is already taking Tylenol for headaches, more acetaminophen (Tylenol) in the form of an over-the-counter cold medication should not be added as  would be reached.
These medications have to be used with an eye to overall daily use and the amount used over a period of time. Used with care acetaminophen remains very safe.

Reference: December 20, 2006 online issue of Time

Last edited December 5, 2012


Acetaminophen And Pets Aggravate Asthma

People with respiratory problems should be cautious in their use of acetaminophen. These are the results of a large cross-sectional study from Great Britain. In the latest piece of mounting evidence British researchers pointed out that people who take acetaminophen regularly are at a higher risk of developing asthma. There are new indications that the drug may worsen respiratory disease and is also linked to COPD (chronic obstructive pulmonary disease).
The study used previously collected data from nearly 13,500 people and was published in the American Journal of Respiratory and Critical Care. It demonstrated that daily users of acetaminophen are more likely to report asthma (odds ratio=1.81) and COPD (odds ratio=1.94) than patients who say that they never used acetaminophen. The study also investigated the relationship between respiratory illness and ASA as well as ibuprofen. Neither of the two seemed to be significantly related to the incidence of respiratory illness. The team of authors led by Dr. Tricia McKeever of the University of Nottingham did spirometry (lung function tests) and found that daily acetaminophen users had an impaired lung function of a 54 ml lower forced expiratory volume per second (FEV1). Ibuprofen users taking the medication between 1 and 5 times a month showed improvement of a 20 ml increase in FEV1. The benefit did not appear in non-users and those who took the medication on a daily basis.

Acetaminophen And Pets Aggravate Asthma

Acetaminophen And Pets Aggravate Asthma

The researchers strongly recommend that patients with respiratory disease should consult with a physician and consider carefully, whether or not to take acetaminophen.
Helping asthmatics to breathe easier has also been the subject of Japanese research. In a small prospective study Japanese researchers compared the need for inhaled corticosteroids between two groups of patients with allergic asthma. One group found new homes for the pets they were allergic to; the other opted to keep the animal at home. At the end of the 15-month average follow-up none of those who removed the pet were taking daily corticosteroids. Opposed to the first group, all but one of the patients who continued to live with their cat, dog, hamster or ferret were on daily corticosteroid treatment ranging from 200 mcg to 1600 mcg per day. Many asthma patients with animal allergies refuse to part with furry friends, but those who can fare better with less medication.

More info on asthma: http://nethealthbook.com/lung-disease/asthma-introduction/

Reference: The Medical Post, May 31, 2005, page 49 and 50

Last edited October 28, 2014