Acetaminophen: Quietly Hard on the Liver
Acetaminophen—the same ingredient found in regular Tylenol—is one of the most widely used pain relievers in the U.S. It’s inexpensive, easy to find, and easier on the stomach than drugs like ibuprofen. However, it places a heavy burden on the liver.
When you take acetaminophen, your liver processes it. During that process, a small amount of a toxic byproduct called NAPQI is produced. Under normal circumstances, your body neutralizes this toxin using an antioxidant called glutathione, preventing harm.
But if you:
Take too much acetaminophen in one day,
Use it regularly over time, or
Have low levels of glutathione (which can happen if you drink alcohol frequently, are malnourished, or have certain health conditions),
…then your liver may not be able to keep up. That toxic byproduct, NAPQI, starts to build up. It binds to your liver’s cells, damaging them and, in severe cases, triggering liver failure.
Dr. Melillo says that 4,000 milligrams of acetaminophen per day is the max safe dose for most adults. That’s roughly eight Tylenol PM tablets in 24 hours. It’s surprisingly easy to cross that line—especially since acetaminophen hides in many other over-the-counter meds for cold, flu, or sinus congestion.
Why So Many Americans Face Hidden Risk
Experts estimate that roughly one in three Americans lives with some degree of liver disease—more than 100 million people in total. Many of them may be unknowingly putting further strain on their liver through everyday medications they assume are safe.
The concern grew serious enough that in 2011, the U.S. Food and Drug Administration (FDA) took action. Regulators urged drug manufacturers to cap the amount of acetaminophen in combination medications—such as Tylenol PM—at 325 milligrams per tablet.
The reason was clear: research showed that higher doses offered little added pain relief, yet significantly increased the risk of liver damage.
Despite this, Tylenol PM still delivers 500 milligrams of acetaminophen per pill.
Diphenhydramine: Sleep Now, Side Effects Later
The second active ingredient in Tylenol PM is diphenhydramine, better known as Benadryl. This antihistamine is what causes the sedating effect that helps people fall asleep. However, that drowsiness comes with trade-offs—especially when the drug is used regularly rather than occasionally.
Diphenhydramine belongs to a class of drugs known as anticholinergics, meaning it interferes with the brain chemical acetylcholine. This chemical plays a critical role in memory, learning, and overall cognitive performance.
When acetylcholine is blocked too frequently or over long periods, problems can emerge. Research has found that individuals who used anticholinergic medications daily for three years or more faced a 54% greater risk of developing dementia compared with those who used them only occasionally.
Diphenhydramine can also cause a range of side effects, including:
Dry mouth
Lightheadedness or dizziness
Continue reading…