3 Acetaminophen Side Effects and Risks to Know About, And When to Seek Care

Acetaminophen (Tylenol) is a common over-the-counter (OTC) medication. It can be used to manage different types of mild pain, such as headaches, muscle aches, and menstrual pain. Acetaminophen can also lower a fever.

Acetaminophen is widely available online and in any store that sells OTC products. You can find it on its own but also in several combination products containing other medications. Since acetaminophen is widely available, it’s important to know about its risks. Acetaminophen side effects are rare, but in some cases they can be severe and have lasting effects.

Acetaminophen side effects and risks at a glance

In general, acetaminophen is well tolerated, and side effects are rare. Still, acetaminophen side effects are possible. Serious risks include liver damage and severe skin reactions. Overdose is also possible and potentially life-threatening.

Below, we’ll discuss these three rare, but potentially severe, acetaminophen risks. Keep in mind, this isn’t a complete list. Other acetaminophen risks can also happen.

1. Overdose

Overdose is a serious risk of acetaminophen. Although over 60 million people in the U.S. take acetaminophen on a daily basis, some don’t even know they’re taking it. This is because several OTC and prescription products contain acetaminophen. Examples include NyQuil Cold & Flu (acetaminophen / dextromethorphan / doxylamine), Excedrin Migraine (acetaminophen / aspirin / caffeine), and Percocet (oxycodone / acetaminophen). Taking several medications that include acetaminophen increases your risk of taking too much.

Acetaminophen overdose can happen in children and adults. You may not experience symptoms at first. Or you may experience vomiting, pain in the upper-right part of your stomach (where your liver is), and confusion. These symptoms may indicate liver damage, the most commonly discussed risk of acetaminophen overdose. In fact, acetaminophen overdose is one of the most common causes of liver failure.

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Additionally, you can experience kidney failure, coma, and even death from acetaminophen overdose. Not peeing, dark-colored urine, and swelling are signs of kidney failure. This may occur with or without liver problems, though it’s much less common than liver damage.

Because the consequences of acetaminophen overdose can be severe (including permanent liver damage if you wait too long to get help), call Poison Control at 1-800-222-1222 if you think you’ve taken an extra dose of acetaminophen. If you know you’ve taken an excessively large amount, or if you experience any symptoms, seek emergency care by calling 911 or going to the emergency room.

Good to know: It’s important to read medication labels and check for acetaminophen in every product you take. If you’re not sure whether a medication contains acetaminophen, ask your pharmacist. They’ll be able to check labels and let you know.

2. Liver Damage

The liver is the organ that metabolizes (breaks down) acetaminophen. It’s metabolized into several substances, most of which are harmless. But some of the acetaminophen you take is metabolized into a toxic chemical.

Typically, your liver can change this toxic chemical into a nontoxic form that you pee out. But in some cases, especially if you take too much acetaminophen, your liver may not be able to keep up. This toxic chemical can build up and lead to liver failure, which can be life-threatening. Occasional, as-needed acetaminophen doses don’t usually cause liver damage. In most cases, this acetaminophen side effect is a risk only if you take too much.

Drinking alcohol with acetaminophen, especially large amounts of alcohol, can also raise your risk of liver damage. That’s why it’s important to pay close attention to how much acetaminophen you’re taking. The maximum daily dosage for most adults is 4,000 mg per day. But if you’re taking acetaminophen for more than 7 days in a row, some experts suggest a lower dosage of 3,250 mg per day at most. And some people — such as those with liver disease — may be better off taking even less than 3,250 mg per day.

Each acetaminophen product, including regular-strength (325 mg) tablets and extra-strength (500 mg) tablets, has different dosage recommendations on its label. Often, the dosage recommended on the label is less than 4,000 mg per day. Follow the instructions for your individual product, and talk to a healthcare professional about the best dose for you.

Signs of liver damage from acetaminophen

The signs of liver damage from acetaminophen can vary. Initially, you may not have any symptoms. But as liver damage progresses, symptoms may include:

• Vomiting

• Pain in the upper-right part of your stomach (where your liver is)

• Low blood pressure

• Yellowing of the skin and eyes (jaundice)

• Bleeding

• Confusion

• Irregular breathing and fast heartbeat from metabolic acidosis

In the most severe cases, death can occur. This is why you should seek emergency care if you experience any signs of liver damage. If you’re not experiencing symptoms, but you know you’ve taken too much acetaminophen, you should still seek emergency care or call Poison Control at 1-800-222-1222.

3. Skin reactions

Rarely, acetaminophen can also cause rashes and other skin reactions. You may see an obvious skin rash or skin that appears red, peeling, or blistering. You may experience hives or itching.

Rarely, a skin rash from acetaminophen can be a sign of serious skin reactions. Examples include Stevens-Johnson Syndrome, toxic epidermal necrolysis, and acute generalized exanthematous pustulosis.

These reactions can occur anytime during treatment with acetaminophen. So if you develop a skin rash while taking acetaminophen, even if it’s mild, stop taking it. Seek medical attention immediately. Mild rashes can quickly progress to serious skin reactions. Severe reactions can cause swelling and make it difficult to breathe.

If you experience a skin rash from acetaminophen, your healthcare professional will likely recommend avoiding it. In this case, nonsteroidal anti-inflammatory drugs (NSAIDs) may be a good option. These include ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn).

But NSAIDs can also cause skin reactions. So you’ll still want to watch out for rashes with these medications. It never hurts to check with your healthcare professional before taking an NSAID. They’re not the best pain relievers for everyone. For example, people with kidney or heart issues may need to avoid NSAIDs.

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Written by:

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP, has over a decade of experience as a pharmacist, professor, and researcher. She was a full-time clinical professor in the pharmacy practice department at D’Youville School of Pharmacy before subsequently joining the faculty of the pharmacy practice department at the University at Buffalo School of Pharmacy and Pharmaceutical Sciences.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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