Tylenol May Negatively Affect Male Sexual Behavior: Study

New research suggests that the side effects of Tylenol and other drugs containing acetaminophen may include a negative impact on the sexual function of men whose mothers used the popular pain drug during pregnancy. 

In a study published last week in the medical journal of the Society for Reproduction and Fertility, Reproduction, researchers from Denmark warn about the potential risks associated with prenatal exposure to acetaminophen, which is known as paracetamol in that country.

The study looked at prenatal exposure to acetaminophen among male mice, giving them doses close in comparison to those recommended for pregnant human females. The findings suggest that the popular analgesic may reduce sex drive and cause aggressive behavior among males.

Although the study was conducted on mice, researchers were sufficiently certain about their findings to suggest that it would be unethical to conduct the same experiments on pregnant women.

Researchers found that prenatal exposure to acetaminophen affected gender characteristics in the brains of the male mice, affecting urinary marking behavior, and reducing territorial displays towards intruders of the same gender. They also had reduced ejaculations during mating, as well as other side effects.

“Together, these data suggest that prenatal exposure to (acetaminophen) may impair male sexual behavior in adulthood by disrupting the sexual neurobehavioral programming,” the researchers concluded. “These findings add to the growing body of evidence suggesting the need to limit the widespread exposure and use of {acetaminophen) by pregnant women.”

In July 2016, a study by Spanish researchers reported that women who used acetaminophen during pregnancy had twice the risk of giving birth to a child with hyperactivity and impulsivity symptoms. Earlier that same year, researchers from Norway published a study in the same journal warning that exposure to Tylenol during pregnancy and shortly after birth could result in an increased risk of asthma.

Although most concerns assume Tylenol is safe, acetaminophen products have been linked to a number of potential health risks. The pain killer has been identified as a leading cause for liver injury in the United States, causing an estimated 50,000 emergency room visits each year, including 25,000 hospitalizations and over 450 deaths annually. In addition, use of the medication has been linked to a risk of dangerous skin reactions, like Stephens-Johnson Syndrome.

In recent years, efforts have been ramped up to bring the risk of acetaminophen overdoses to the public’s attention and to reduce the amount of liver injury cases linked to the popular analgesic, which is also found in other pain killers and a number of cold medications.

In 2011, Johnson & Johnson lowered the maximum recommended dosage on Tylenol and other acetaminophen-based products from 4,000 mg per day to 3,000 mg per day. However, the drug maker faced a number of Tylenol liver failure lawsuits, which involved allegations that important safety information from the public for decades.

In February, about 200 of those lawsuits were settled out of court, but the details of that settlement were undisclosed.