Experts estimate that roughly one in three Americans suffers from liver disease – a total of more than 100 million people. Many of them may unknowingly be putting additional strain on their livers through everyday medications that they consider harmless.
Concerns grew so much that the US Food and Drug Administration (FDA) took action in 2011. Regulators required drug manufacturers to limit the amount of acetaminophen in combination products – such as Tylenol PM – to 325 milligrams per tablet.
The reason was clear: studies showed that higher doses provided little additional pain relief but significantly increased the risk of liver damage.
Nevertheless, Tylenol PM still contains 500 milligrams of paracetamol per tablet.
Diphenhydramine: Sleep first, then side effects.
The second active ingredient in Tylenol PM is diphenhydramine, better known as Benadryl. This antihistamine produces the calming effect that helps with falling asleep. However, this drowsiness also has disadvantages – especially with regular rather than occasional use.
Although it may make falling asleep easier in the short term, repeated use can have cognitive and neurological consequences that many users never foresee.
Diphenhydramine belongs to the group of anticholinergics, meaning it inhibits the action of the neurotransmitter acetylcholine in the brain. This plays a crucial role in memory, learning, and general cognitive performance.
Problems can arise if acetylcholine is blocked too frequently or for an extended period. Studies have shown that individuals who took anticholinergics daily for three years or more had a 54% higher risk of developing dementia than those who took them only occasionally.
Diphenhydramine can also cause a number of side effects, including:
dry mouth
Drowsiness or dizziness
Confusion, especially among older adults
Urinary retention, which can lead to further complications in older people.
Dr. Melillo points out that while these effects may seem mild on their own, they can trigger or worsen age-related problems – increasing the risk of falls, dehydration, and delirium attacks.
Tylenol PM and riskier decisions?
And here comes an unexpected twist: Paracetamol can influence how you feel – and how you assess risks.
In a 2020 study from Ohio State University, participants received either 1000 milligrams of acetaminophen or a placebo. They were then asked to assess the risk of various activities, from skydiving and bungee jumping to major life decisions such as changing careers.
The results were surprising. Those who had taken paracetamol consistently rated these activities as less risky than the participants who had not taken the medication. Researchers suspect that the drug dampens emotional reactions and reduces feelings such as anxiety and excitement.
Previous research supports this assumption, showing that paracetamol can also reduce empathy, dampen emotional responses to the pain of others, and even suppress positive feelings such as happiness.
In other words, this widely used medication may do more than just relieve pain or help you fall asleep. It could subtly alter how you experience emotions and perceive your environment.
What should you do instead?
Dr. Melillo is not calling for Tylenol PM to be withdrawn from the market. He agrees that it can be helpful on occasion. However, he is adamant on one point: it should not become an evening habit.
For persistent sleep problems, he recommends speaking with a doctor or pharmacist about possible options, such as:
Sleeping pills that do not cause addiction
Melatonin or other natural dietary supplements
Improving sleep habits – less screen time, avoiding caffeine after lunch and maintaining a regular bedtime.
According to research findings, cognitive behavioral therapy for insomnia (CBT-I) is more effective than medication over time.
If nighttime pain is the real problem, you should consider the following approaches:
Take paracetamol only when needed, not routinely.
Using different painkillers instead of relying on the same one every day.
Try non-drug strategies such as heat therapy, massage, or gentle stretching exercises.
The goal is not to eliminate relief, but to find safer, longer-term solutions that do not create new problems while solving old ones.
Conclusion: Caution is advised.
Tylenol PM may seem like a simple solution for pain and sleepless nights, but behind the reassuring label lies a more complicated story.
The risks – liver damage, memory problems, emotional blunting, and even dementia – are real, especially with regular use. Therefore, Dr. Melillo strongly advises against using the medication only occasionally and recommends carefully reviewing the ingredients of the tablets being taken.
As he puts it:
“If you only take it occasionally, that’s fine – no problem. But it shouldn’t be your standard medication for sleeping… because you want to avoid long-term complications.”
Your medicine cabinet may be well-stocked, but your health deserves well-considered decisions. It’s not about fear, but about awareness. Because the best health tips often sound quite simple: Use with caution, read the package insert, and ask questions.
