Painful headache or achy back keeping you awake? Before you reach for the Tylenol PM, Excedrin PM, Midol PM, or any other acetaminophen PM painkiller, read this guide to help you safely get the relief you need!
What You Need to Know About Tylenol PM
Tylenol PM is a common, widely available medication. But what do you need to know before you take it? In this guide, we’ll provide seven key facts about acetaminophen diphenhydramine combination medications like Tylenol PM, including Tylenol PM ingredients, Tylenol PM side effects, and any warnings you need to be aware of.
#1: Tylenol PM Is an OTC Pain Reliever and Antihistamine
Tylenol PM is a common over-the-counter (no prescription needed!) combination pain reliever and sleep medication.
What is in Tylenol PM? The main active Tylenol PM ingredients are acetaminophen and diphenhydramine. Acetaminophen is a pain reliever that works primarily by inhibiting our perception of pain in the central nervous system. In other words, it doesn’t address the underlying cause of the pain, but it makes you less able to perceive that pain.
Diphenhydramine is actually an antihistamine—it’s the active ingredient in Benadryl. When you have an allergic reaction, histamines are the compounds in the body that make your nose runny and sneezy, your skin itchy, and your eyes burn. But histamines also help regulate sleeping and waking. Thus, some antihistamines (like diphenhydramine) also make you drowsy. So even though it was initially meant to be an allergy medicine, diphenhydramine is now one of the most common over-the-counter sleep aids!
Note that Tylenol PM (and Excedrin PM and Midol PM) is different from over-the-counter NSAID nighttime painkillers like Advil PM, Motrin PM, and Aleve PM. These products use a non-steroidal anti-inflammatory drug or NSAID like ibuprofen or naproxen as their pain-relieving ingredient. NSAIDs are more effective for joint and muscle aches and cramps but are hard on the gastrointestinal system. These PM formulations still have diphenhydramine as the sleep aid ingredient.
For stubborn pain, you can safely take both acetaminophen and an NSAID—but you shouldn’t take the PM version of both at the same time because you’ll end up with twice as much diphenhydramine as you need.
#2: Tylenol PM Will Make You Drowsy
Unsurprisingly, because it is supposed to help you sleep through pain, one of the main Tylenol PM side effects is drowsiness. Diphenhydramine can also cause dizziness, blurry vision, and difficulty concentrating. As such, you should never drive or operate dangerous machinery after taking Tylenol PM.
Other common Tylenol PM side effects include constipation, dry mucous membranes (nose/mouth/etc), gastrointestinal distress, and mild skin rash.
Discontinue use and seek medical help if you experience any of the following unusual and serious side effects: slowed or shallow breathing, severe skin rash, inability to urinate, confusion, tremors, jaundice, light-colored stools, or heart palpitations.
#3: Tylenol PM Overdose Can Be Deadly
One of the main negative side effects of acetaminophen (and thus a major Tylenol PM side effect) is that overuse of acetaminophen can damage the liver. Taking too much acetaminophen in a short period of time can lead to liver failure and death.
Tylenol PM dosage (and dosage for similar products) is typically two pill tablets taken 20-30 minutes before bed. This should comprise a total of 50 mg of diphenhydramine (or 76 mg of diphenhydramine citrate) and no more than 1,000 mg of acetaminophen.
1000 mg is the maximum dose of acetaminophen advised at one time. The maximum daily dose is 4,000 mg. So if you’ve been taking regular Tylenol during the day, make sure that your Tylenol PM dosage won’t put you over the edge. In fact, because of the potential for liver toxicity, it’s better to stay at a more conservative 3,000 mg/day if you can. Additionally, try not to take a max dose for more than a few days running unless you’re being advised by a medical professional.
Note that many combination medicines contain acetaminophen. Thus, it is critical that you look at the active ingredients in all medicines you take to be sure that you do not overdose on acetaminophen.
Also note that you should not use Tylenol PM solely as a sleep aid. If you aren’t experiencing pain, there’s no reason to tax your liver by taking acetaminophen! Take plain diphenhydramine (found in Benadryl, Zzzquil, Unisom, and many generic formulations) or another dedicated over-the-counter sleep aid instead.
#4: Don’t Drink Alcohol on Tylenol PM
Combining Tylenol PM and alcohol is very dangerous because alcohol interacts with both of the active ingredients in Tylenol PM. First, it amplifies the toxic effects of acetaminophen on the liver. While you are taking acetaminophen, it’s best to abstain from drinking completely.
Alcohol also amplifies the effects of diphenhydramine, causing increased drowsiness and impairment of motor skills.
#5: Tylenol PM Gets Less Effective for Sleep Over Time
Occasionally taking Tylenol PM to help you sleep through a bothersome nighttime headache is fine. However, over time, your body will acclimate to the effects of diphenhydramine and a standard dose may not make you drowsy anymore.
If you are having consistent trouble sleeping, it’s much better to try to practice sleep hygiene and/or see a medical professional instead of relying on over-the-counter sleep aids for long amounts of time.
#6: Tylenol PM Is Not Safe for Everyone
Not everyone can safely take Tylenol PM. The sedating side effects of Tylenol PM may be more pronounced in the elderly, so it should be used with caution in this population. Furthermore, you should not take Tylenol PM without first consulting a doctor if you have any of the following conditions:
- Kidney or liver issues
- A blockage in the intestinal tract
- Breathing problems like asthma or emphysema
- Chronic obstructive pulmonary disease
- Difficulty urinating
- Stomach ulcer
You should also consult with a doctor on whether it is safe for you to take acetaminophen (found in Tylenol PM) if you are taking warfarin or sedative substances.
#7: Be Cautious With Tylenol PM While Pregnant
Can you take Tylenol PM while pregnant? Tylenol PM during pregnancy and breastfeeding is probably safe. However, acetaminophen is considered a “category C” substance by the FDA, meaning that risk to a human fetus cannot necessarily be ruled out. Furthermore, the effects of diphenhydramine on a fetus when transmitted through breast milk are not well known. Thus, you should consult with your doctor about taking Tylenol PM while pregnant or breastfeeding.
Recap: 7 Key Facts on Tylenol PM
- The two active Tylenol PM ingredients are acetaminophen, a painkiller, and diphenhydramine, an antihistamine that doubles as a sleep aid. These are the same active ingredients in products like Excedrin PM and Midol PM, but different from the PM versions of NSAID painkillers.
- Tylenol PM will make you drowsy, so don’t try to drive on Tylenol PM!
- Acetaminophen is very hard on your liver, so never take more than the recommended dose of Tylenol PM and track your daily acetaminophen intake carefully.
- Drinking alcohol on Tylenol PM is very dangerous as it magnifies the toxic effects on your liver and the sedating effects of diphenhydramine.
- The sleep-inducing effects of Tylenol PM will fade if you take the drug too regularly.
- If you have a pre-existing medical condition, check with your doctor before taking Tylenol PM.
- It’s not known if taking Tylenol PM while pregnant or breastfeeding is completely safe, so consult with your doctor.